Welcome to the Huberman Lab Podcast,

where we discuss science

and science-based tools for everyday life.

I’m Andrew Huberman,

and I’m a professor of neurobiology and ophthalmology

at Stanford School of Medicine.

Today, we are going to talk about the psychology

and the biology of desire, love, and attachment.

Today happens to be Valentine’s Day, 2022.

However, the themes we are going to discuss

pertain to desire, love, and attachment

on any given day.

And indeed, the mechanisms we are going to discuss

almost certainly were at play thousands of years ago,

hundreds of years ago,

and no doubt will still be at play in our minds

and in our bodies and in our psychologies

for the decades, centuries, and thousands of years to come.

Indeed, today I want to focus on core mechanisms

that lead individuals to seek out other individuals

with whom to mate with,

with whom to have children with or not,

with whom to enter short or long-term relationships with,

and perhaps to end those relationships

or to seek relationships on the side, so-called infidelity.

I’m certainly not going to encourage

or discourage any of these behaviors.

I’m simply going to cover the peer-reviewed scientific data

on all these aspects of desire, love, and attachment.

I’m going to discuss how our childhood attachment styles,

as they’re called,

influence our adult attachment styles.

Yes, you heard that right.

How we attached or did not attach to primary caregivers

in our childhood has much to do with how we attach

or fail to attach to romantic partners as adults

because the same neural circuits,

the neurons and their connections in the brain and body

that underlie attachment between infant and caregiver,

between toddler and parent or other caregiver,

and during adolescence and in our teenage years

are repurposed for adult romantic attachments.

I know that might be a little eerie to think about,

but indeed that is true.

Now, the fortunate thing is that regardless

of our childhood attachment styles and experiences,

the neural circuits for desire, love,

and attachment are quite plastic.

They are amenable to change in response

to both what we think and what we feel

as well as what we do.

However, all three aspects that we’re discussing today,

desire, love, and attachment

are also strongly biologically driven.

We’re going to talk about biological mechanisms

such as hormones,

biological mechanisms such as neurochemicals,

things like dopamine, oxytocin, and serotonin,

and neural circuits, brain areas,

and indeed areas of the body that interact with the brain

that control whether or not we desire somebody or not,

whether or not we lose or increase our desire

for somebody over time,

whether or not we fall in love,

what love means,

and whether or not the relationships we form

continue to include the elements of desire and love

over time or not.

In order to illustrate just how powerfully our biology

can shape our perception of the attractiveness

of other people,

I want to share with you the results of a couple of studies.

Both studies explore how people rate

other people’s attractiveness.

And in both studies,

the major variable is that women are at different stages

of their menstrual cycle.

Now, in the first study,

men are rating the attractiveness of women

according to the smell of those women.

Now, they’re not smelling them directly.

They’re smelling clothing that women wore

for a couple of days at different phases

of their menstrual cycle.

And what they find is that men will rate the odors of women

as most attractive if those women wore those shirts,

that clothing, in the pre-ovulatory phase of their cycle.

Okay, so this is not to say that men do not find

women attractive at other stages of their cycle.

It is to say that men find women’s odors

particularly attractive if those odors were worn by women

that are in the pre-ovulatory phase

of their menstrual cycle, okay?

Now, there was also a study that was done

where women at different stages of their menstrual cycle

are rating the odors of men.

And a similar but mirror symmetric result was found

such that women who are in the pre-ovulatory phase

of their menstrual cycle will rate men’s odors

as more attractive than at other stages of their cycle.

So the simple way to put this is that there seems

to be something special about the pre-ovulatory phase

of a woman’s menstrual cycle that makes men rate them

as more attractive during that time,

and women rate men as more attractive

during that particular time as well.

So this is a bi-directional effect.

The way that the second study was done

where women are rating men was not just to smell the odors

of those men on t-shirts, they did that,

but they correlated that with whether or not

the shirts were worn by men

that were particularly physically symmetrical.

They actually had these men divided into groups,

it was more of a continuum rather,

rated according to body symmetry and face symmetry.

And women preferred more symmetrical men

when they were doing the preference test

during the pre-ovulatory phase of their cycle.

So again, the point is that that pre-ovulatory phase

of the cycle seems to create

a bi-directional mutual attractiveness.

Now, also extremely interesting is that this effect

does really seem to have something to do with ovulation,

because in both studies, they had women

that were taking oral contraception or not,

and what they found was

if a woman is taking oral contraception,

it prevented that peak in perceived attractiveness

by the men, meaning men no longer perceived a woman

to be more attractive at a particular phase of their cycle.

And also, women taking oral contraception

no longer prefer the odors of more symmetrical men

during the pre-ovulatory phase of their cycle.

Now, I want to make sure that it’s especially clear

that it is not the case that oral contraception

reduced the perception of a woman as attractive,

that did not happen in these studies.

It reduced the further increase

in a male’s perception of her as attractive,

and if women took oral contraception,

it prevented them from preferring more symmetrical men

based on the odors of those men.

Now, I realize there are a lot of variables here.

We’ve got odors, we’ve got symmetry,

we’ve got menstrual cycle, pre-ovulatory, non-pre-ovulatory,

and we have whether or not

people are taking contraception or not.

But the basic finding is that depending on where women are

in their menstrual cycle influences

both men’s perception of them as attractive

and their perception of men as attractive,

and oral contraception eliminates that effect.

So I share with you those data to illustrate

that we often think that somebody is attractive or not

based on, I don’t know how they look,

their skin, their hair, et cetera,

but it also illustrates that their odor is a powerful cue

for some people more than others.

You know, some of us tend to be

more olfactory driven than others.

Although if you watched the Huberman Lab podcast episode

that I did with Professor David Buss

from the University of Texas, Austin,

who’s a luminary in the field of evolutionary psychology

and has studied mate choice

and mate selection bias over decades.

He’s really one of the founders of that field.

He emphasized findings that odor for many people

is a maker or a deal breaker.

Meaning there are some people that even if somebody

has all the characteristics that they’re looking for

in terms of kindness and attractiveness and values

and other features that would and should be

of very high priority in selecting a mate,

that if someone does not like the way that person smells,

their innate body odor, independent of colognes and perfumes

and soaps, et cetera,

that that’s often a complete and total deal breaker.

I’m sure there are some of you that can relate to that.

And there are some of you perhaps for which

that is not the case.

And you can’t even imagine that being

such a powerful variable.

And yet the data suggests that indeed

it is a powerful variable for many people out there.

Before we begin,

I’d like to emphasize that this podcast is separate

from my teaching and research roles at Stanford.

It is however,

part of my desire and effort to bring zero cost

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Let’s talk about desire, love, and attachment.

And of course, these are topics

that grab tremendous interest,

so it’s worth us defining our terms a little bit

before going any further.

Of course, we can have many different kinds of loves.

There’s romantic love.

There’s love of family, so-called familial love.

There’s love of pets.

We can even love objects,

or we can feel as if we love objects.

We can love certain activities.

We can have friends that we love, and so on and so forth.

The word love is used to encompass

a lot of different types of relationships.

Today, we are mainly going to be focused on romantic love

and the neural mechanisms of romantic love.

I want to acknowledge here at the outset

that most of the studies of romantic love

have focused on monogamous heterosexual love.

And also, when we talk about studies focused on desire

and attractiveness and attachment, that’s also the case.

And that simply reflects the general bias of the literature

over the last 50 to 100 years.

It does, of course, not rule out that similar

or different mechanisms could be at play

in non-monogamous relationships,

in homosexual relationships,

or in relationships of any kind or variation.

It’s also worth us defining our terms around desire.

It can mean lust.

It can mean the desire for long-term partnership.

So we need to define our terms.

And throughout, I will do my best

to very carefully define what I mean by desire,

what I mean by love, and what I mean by attachment.

The formal study of love and desire and attachment

goes back to the early 1900s.

One of the classic studies on this

is entitled Love and Desire.

It was published in 1912 and really focused

on two opposing themes within romance.

One is love, which in that paper

was really meant to include attachment

and dependence or interdependence between individuals.

And the other end of the spectrum being desire

or the sexual desire for another.

And romance was meant to encapsulate both those things,

love and desire.

And for much of the 1900s,

it was thought that love and desire

were on sort of opposing ends or in kind of a push-pull.

And it was the dynamic push and pull

between love and desire that one could define romance.

And that actually led to much of what’s out there

in the psychological literature.

Today, we are going to explore

some neurobiological studies,

some studies of the endocrine system,

meaning the hormone system,

that actually support that general model.

And I’ll point you toward what I think

is a very useful book in thinking about

how relationships can both form and last

over long periods of time,

and how those relationships can include

both desire and interdependence.

I’ll also talk about some studies

that have really focused on why relationships succeed

and why they fail and how that relates

to whether or not there is sufficient amounts

of attachment and desire.

So today we’re going to talk about the science

and indeed you’ll also get some tools.

Those tools should be useful to you,

whether or not you happen to be in a relationship or not,

whether or not you’re seeking a relationship or not.

I’d like to begin with an anecdote,

and this is not an anecdote about my relationship history.

It’s a anecdote about my scientific history.

When I started graduate school,

the chairman of the department I was in at the time

said to me, you know, most PhDs last longer

than most marriages.

And indeed he was right.

And also most marriages in this country end in divorce.

I think it’s about 50% with a slight skew

toward more ending in divorce than persist

until death do them part.

But nonetheless, it’s about half.

And most marriages end before the eight-year period is up.

Most PhDs take anywhere from four to nine years.

So there was a bit of a smearing of averages there,

but the point he was trying to make

really landed home for me.

It did not scare me out of relationships,

nor did it scare me out of a PhD, obviously.

What it did illustrate was that there’s something

about our attachment machinery

that can be very, very compelling,

such that people take on tremendous levels of commitment.

I have to imagine that most people enter marriages

assuming that they’re going to stay in those marriages.

I don’t think most people enter marriages

thinking they’re going to get divorced,

but that if 50% of those commitments end in divorce,

there must also be mechanisms

by which our attachments can break.

And today we’re going to talk about

both the forming of attachments

and the breaking of attachments,

what can prevent those breaks and attachments,

and indeed what can lead to reattachments.

There are biological mechanisms

to desire, love, and attachment.

That’s abundantly clear.

Now, there’s a robust and very large literature

in animal models.

What I mean by that are field studies and laboratory studies

in primates of different kinds,

such as macaque monkeys or bonobos.

People have looked at these sorts of things,

believe it or not, in ducks, in laboratory mice,

in different types of birds, et cetera.

And if you look at that literature,

you can essentially find biological examples

in the animal kingdom for just about any behavior

that you can easily map to human behavior.

So for instance, there’s a species of animal

called the prairie vole.

In one portion of the United States,

this prairie vole species is monogamous.

They only mate with one other prairie vole,

only raise young with one other prairie vole

for their entire life.

And in another region of the United States,

the same species of animal, the prairie vole,

will mate with many individuals.

They’re non-monogamous.

And the major difference, at least as far as we know,

between the prairie voles in one location

and another location is the levels

of a molecule called vasopressin in the brain and body.

Vasopressin is present in humans.

It has numerous biological roles.

It’s responsible, for instance,

for controlling the amount of urine that you excrete,

the amount of water that you retain,

and for sexual desire, as well as mate-seeking.

Levels of vasopressin in prairie voles

are strongly determinant of whether or not

a prairie vole is going to be monogamous or non-monogamous.

Why do I raise this?

Well, I raise this because the literature on prairie voles

is quite beautiful and has been discussed quite a lot

in the popular press.

You can look it up with an easy,

easily just a web engine search.

You’ll find lots of information about this,

lots of news articles about this,

and lots of interpretations as to how vasopressin

might be involved in similar

or different mechanisms in humans.

Now, I don’t have a problem

with mapping animal studies to humans.

I think there’s certainly a place for that.

But if we just sort of lean back

and look at the giant mass of studies in animals

and their mating behavior and their mate selection behavior,

you can essentially find examples of anything.

You can find examples of polygamy.

You can find examples of cheating, of infidelity.

You can find examples of all sorts of different behaviors

that in your own mind, you can map to human behavior.

But it’s really hard to make the leap from animal models

to humans in any kind of direct way.

And so thankfully, there’s been tremendous work done

in the last mainly 20 years or so

looking at human mate selection, human desire,

human love, and human attachment.

So we’re mainly going to focus on those studies today.

And where appropriate, we will map those findings

back to the findings in animals

to see if there’s some universal truths

or some universal principles

about how the neural circuits

and biological mechanisms work.

But by and large, we’re going to focus on human studies today

so unless I say otherwise,

the data that I’m referring to today

are entirely from human beings.

So let’s talk about attachment and attachment styles.

And this will offer you the opportunity

to answer some important questions for yourself,

such as what is my, meaning your,

attachment style in relationship?

One of the most robust findings in the field of psychology

is this notion of attachment styles.

And this was something that was discovered

through a beautiful set of studies

that were done by Mary Ainsworth in the 1980s,

in which she developed a laboratory condition

called the strange situation task.

Now, the strange situation task has been studied

over and over again in different cultures,

in different locations throughout the world.

And in preparing for this episode,

I actually spoke to three different psychologists.

I spoke to a psychoanalyst,

I spoke to a cognitive behavioral psychologist,

and I actually spoke to a psychiatrist,

excuse me, not a psychologist,

but a psychiatrist with a medical degree and asked,

is the strange situation task

and the various attachment styles

that emerge from that task,

are those still considered valid?

And indeed, all three of them said,

if ever there was a literature in psychology

that is absolutely tamped down and has a firm basis

in both data and real world principles

and real world examples,

it’s this notion of attachment styles.

So what is the strange situation task?

The strange situation task involves a parent,

typically a mother in the studies that were done,

but a parent or other caregiver bringing their child,

their actual child into a laboratory.

And there’s a room with a stranger

and the mother enters the room with the child

and there’s some toys in the room.

And typically the mother and the stranger will talk.

Obviously the stranger is part of the experiment,

it’s not just some random person off the street.

And the child is allowed to move about the room.

They can observe the mother interacting

with the other person or not.

They can play with toys or not.

But then at some point, the mother leaves.

And then at some point later,

designated by the experimenter, the mother comes back.

And what is measured in these studies

is both how the child, the toddler,

reacts to the mother leaving

and how the child reacts to the mother returning

at the end of the experiment.

And oftentimes this will have two or three different phases

where the mother will bring the child in, then leave,

then come back in and leave.

There are also studies in which the behavior

of the child with the stranger is also examined.

So there are a lot of variations of this,

but the basic findings are that toddlers, children,

fall into four different categories of attachment style.

And that these attachment styles can predict many features

of adolescent, teen, young adult,

and even adult attachment styles,

not in strange situations

of the sort that I just described,

but in romantic attachments.

I should mention also that attachment style is plastic,

meaning it can change across the lifespan.

So as I described the results,

I described the different attachment styles

that are out there.

And if any of those resonate with you

or bring to mind certain people in your life,

please do not assume that those attachment styles

are rigid and fixed for the entire lifespan.

There are also terrific data that indicate

that through specific processes,

both psychological and some biological adjustments,

that people can change their attachment style.

And that indeed people who have different attachment styles

can change the attachment styles of others.

But just to make very clear

what the results of the study were,

I want to review what the four different

attachment styles are.

And typically people fall into one group or another,

but not several.

So the four patterns of attachment

that were revealed by these studies,

again were revealed by examining the behavior of the child

in response to the mother leaving and the mother returning

and the child’s response to the stranger

that is in the room with them.

The first style is the so-called secure attachment style.

In the nomenclature of this kind of study,

these are the so-called B babies

as in the letter B, bulldog, B.

Not for bulldogs, but just to designate this category.

The secure attachment style is one in which the child

will engage with the stranger, with the experimenter,

while the parent is present in the room.

But that when the parent, typically it’s a mother,

but when the parent or other caregiver leaves,

the child does get visibly upset.

They might whine, they might cry,

they might even tantrum a bit.

However, when the caregiver,

meaning the mother or father or other caregiver returns,

the child visibly expresses happiness

that the caregiver has returned.

So that’s the hallmark of the secure attachment style.

And again, this is all pre-verbal.

This is happening long before the child can express

how they feel with words.

And the interpretation of this is that the secure child

feels confident that the caregiver is available

and will be responsive to their needs

and their communications.

So that when the child whines and or is distressed,

the parent doesn’t come right back into the room,

but at some point they do.

And they seem to have a sense of trust

that if the parent or caregiver leaves,

that the parent will come back

and that they’re happy that they do.

These children are also very good

at exploring novel environments after the parent is gone

and while the parent is there.

And almost always when the parent is there,

they will explore more broadly, literally in space.

They’ll venture out further than they will

when the parent is gone.

They also tend to engage with the caregiver in a way

that’s not immediately and completely trusting,

but that over time seems to evolve

from one in which they’re kind of suspicious of this person

to one in which they’re at least somewhat trusting.

Okay, so those are the general contours

of the secure attachment style.

And fortunately, nowadays there are physiological studies

measuring things like heart rate and breathing

and other measures that correlate

with the subjective assessment

of what these children are feeling.

Okay, so first category is secure attached.

The second category is a so-called anxious avoidant

or insecurely attached, which are the category A babies.

The children with anxious avoidant

insecure attachment patterns generally tend to avoid

or ignore the caregiver, all right, meaning the parent,

and show very little emotion

when the parent leaves or returns.

So this is the reason they call them avoidant

or anxious avoidant and kind of insecure.

There isn’t this happiness or joy that the parent is back.

They don’t seem to express that.

They do not exhibit distress on separation.

And they generally tend to have some tendency

to approach the caregiver when they return,

but there doesn’t seem to be a general expression of joy.

And again, physiological measures support that as well.

Things like changes in heart rate tend to be less dramatic

in the anxious avoidant insecure attachment style

than in the secure attachment style.

Okay, so that’s the second one.

The third category is the so-called anxious ambivalent

slash resistant insecure category.

Okay, I didn’t name these categories.

So you have to blame others in this one instance.

For everything else, blame me.

But in this instance, you have to blame the psychologists

that named this category.

The anxious ambivalent slash resistant insecure category,

also called the C babies for the letter C

just as a categorization.

The anxious ambivalent resistant insecure toddlers really

show distress even before separation from their mother

or other caregiver.

And they tend to be very clingy and difficult to comfort

when the caregiver returns.

Okay, so they’re distressed even before the mother

leaves the room.

And they tend to be very clingy and really hard to calm down

when the mother returns.

They tend to show either what seems to be resentment

in response to the parent’s absence.

We don’t really know what they’re feeling

or some sort of helpless passivity.

And there’s actually subcategorizations

that the psychologists have come up with,

with C1 subtypes and C2 subtypes.

We don’t have to get bogged down in that.

But just know that there isn’t one absolute measure

that says, oh, well, this person is anxious ambivalent

resistant insecure.

They could be somewhat passive or they could be

somewhat angry at the caregiver.

But the basic idea is that before and after the separation

they are clingy and difficult to comfort.

They just can’t seem to calm themselves down.

And physiological measures of heart rate

and hormone measurements such as cortisol

also support that statement.

And the third category of attachment style

is the so-called disorganized or disoriented

or D for the letter D babies.

This is a categorization that was added later

to this strange situation task.

That is a real hallmark of developmental psychology studies.

It was developed by Mary Ainsworth graduate student,

Mary Maine, who I actually had the great fortune

of taking a course from and learning from

when I was a graduate student at Berkeley many years ago.

And this fourth categorization was controversial

for a while, but now is generally accepted.

The key feature of the disorganized disoriented category

is that the toddlers tend to be tense

and they tend to encompass a lot of

kind of odd physical postures.

They tend to hunch their shoulders.

They’ll put their hands behind their neck.

They’ll cock their head to the side.

For those of you listening,

I’m doing this on the video version.

It’s not where you don’t have to go see that.

But for those of you that are watching this on video,

they tend to kind of constrain their body size a bit

and go into odd postures that they normally

wouldn’t do anywhere else.

So this is why it’s called the disorganized

or disoriented category.

It seems like these children just don’t really know

how to react to a separation.

And they just start to manifest behaviors

and emotional tones that aren’t observed

in other situations.

Okay, so we’ve got our four categories.

I’ll try and use the shortest possible names

for each category.

We’ve got category one, which is securely attached.

We’ve got category two, which is insecurely attached,

also sometimes called anxious avoidant.

Then we’ve got category three,

which is the resistant insecure category,

which is anxious ambivalent.

And then there’s this fourth category,

the disorganized disoriented category

or the so-called D babies.

Now, what’s interesting about this from the perspective

of desire, love, and attachment

is that the categorizations of children

into one of these four different categories as toddlers

is strongly predictive of their attachment style

in romantic partnerships later in life,

which is to me, both amazing and surprising

and not surprising all at the same time.

Amazing because it means that, first of all,

we are relatively hardwired for attachment.

I think that that’s incredible and beautiful

that we have designated neurons, nerve cells,

and hormonal systems that are there to ensure

that we have some sort of response

to a caregiver being there or not being there

or returning or leaving,

but also that the same neural circuitries,

the same hormonal responses are at least in some way

repurposed for entirely different types of attachments

later in life.

So when we hear the psychologists talk about how,

you know, we formed a template early in life

based on experiences that were even pre-verbal

before we had language,

and those templates are superimposed on our relationships

or we should say our later relationships

are superimposed on those templates,

there really is a basis for that.

We now have neuroimaging studies to support,

for instance, the work of Alan Shore from UCLA

showing that when a mother and child interact

either through very soothing interactions

like bottle feeding or breastfeeding

or singing to one’s baby or putting them to sleep,

that the brain of the child and the brain of the mother

are entering a coordinated state of relaxation.

And it’s not one direction, mother to child,

the child is also calming the mother.

Typically these studies were done with mothers,

again, sometimes with fathers, but typically with mothers.

And in addition to that,

when the mother or other caregiver acts very excited

and raises their voice or puts a lilt in their voice

or widens their eyes, that the child will do the same.

And again, there’s a bidirectional interaction

in that case of excitement.

And there’s the release of neurochemicals

like dopamine into the bloodstream,

whereas in the relaxation scenario

and the soothing scenario there’s,

we know the release of things like serotonin and oxytocin.

So the neural systems for attachment

and the neural systems for what we call autonomic arousal

for being alert and calm, don’t act in a vacuum.

They are tethered to other people in our environment.

And of course we know this, right?

We sometimes hear the statement,

no one can make you feel anything.

I’ve always had a little bit of a problem

with that statement.

I don’t think I’m contradicting anyone in particular,

but you hear that a lot.

No one can make you feel anything.

Indeed they can, right?

A physical injury can make you feel something.

If somebody says something that you very much like,

it can make you feel something.

And if somebody says something that you very much dislike,

it will make you feel something.

So the idea that no one can make us feel anything

isn’t actually true.

Our nervous system is tethered

to the nervous systems of others.

And that is true from the very earliest stages

of our lives.

And in this case, we’re talking about

how our templates for attachment in romantic relationships,

how we find them, how we maintain them,

and indeed how we break them and reform them

is based on a template that was established

through an entirely different set of priorities,

which was how we feel safe and secure in novel environments,

depending on whether or not our primary caregiver

is there or not.

Neuroimaging supports that.

When I say neuroimaging, I mean, brain scans support that.

Measures of hormones in the body and brain support that.

Measures of neurochemicals support that.

There’s simply no way around this truth

that we have a set of roadmaps in our mind

that are reused for entirely different purposes

later in life.

That is vitally important to understand

because if one is successful in forming

romantic attachments, maintaining them, et cetera,

or not, does in fact reflect the earlier templates

that you’ve created.

But as I’ve mentioned before,

the good news is that these templates can shift over time.

And one of the more powerful ways

to shift those templates over time

is purely by the knowledge that they exist

and the understanding that those templates are malleable.

They can change through the process of neuroplasticity.

Again, neuroplasticity is just a rewiring

of nerve connections that is very much present in childhood,

but also very much present in adulthood.

So if you’re somebody who you think falls

into category one, two, three, or four,

or you know somebody or involved with somebody

who falls into category one, two, three, and four,

the mere knowledge of that can be very useful.

But you might ask, well, what do I do with that knowledge?

Well, fortunately, both psychologists and biologists

have started to leverage that knowledge

toward establishing better, more secure bonds

in adult romantic relationships.

And there’s a book that has really tapped into this.

I think it’s the first book

that has really addressed this head on.

And that book comes from two Columbia professors.

And the title of the book is

Attached, The New Science of Adult Attachment

and How It Can Help You Find and Keep Love.

The authors of this book are Amir Levine and Rachel Heller.

Again, both of them are skilled academics and researchers

who have really taken the literature that I described

on the strange situation task

and mapped it to adult attachment styles.

And also they’ve mapped out ways

that they’ve observed in their clinical practice

and that is laboratory supported for, for instance,

people that have an anxious ambivalent

or what we would call an insecure attachment style

or for people that fall into the disorganized

or disoriented attachment style,

how they can modify that attachment style

in or out of relationships

in order to establish what I think everybody wants,

which is secure attachment.

Why does everybody want that?

Well, secure attachment allows people

to be both in relationship

or if they choose to be on their own

or to be in relationship,

but physically separated from somebody else

or even emotionally separated from somebody else

and maintain what we call a stable autonomic equilibrium,

the ability to remain calm, clear headed.

You might not like what’s happening,

but you’re able to navigate that

with some sense of clarity and not excessive discomfort.

So is there a goal in all of this stuff

about love, desire, and attachment?

Indeed, there is.

The secure attachment style is the one

that leads to the most stable

and predictable long-term relationships.

Put differently, babies, toddlers, adolescents,

teens, and young adults that have a secure attachment style

are more likely to find and form long-term relationships

than are people in the other categories.

But people in other categories can learn

and eventually migrate into the secure attachment style.

And I think that book, Attached,

I have no affiliation to the authors or the book itself.

I should just mention that.

Attached, the new science of adult attachment

and how it can help you find and keep love.

Really, it sounds very pop psychology-esque,

but it is really grounded

in the research psychology literature.

And there’s also some interesting biology there.

Another point to make about attachment styles

is that it is possible,

and some of you may be familiar with circumstances

whereby people who are securely attached,

either because they grew up in an environment

where secure attachment was cultivated

or because they developed that on their own,

can also migrate out of the securely attached category

into insecurely attached

or into avoidant types of attachment styles

as teens or as young adults

or as adults at any age or any stage of life,

by virtue of being with somebody who has a different,

perhaps less adaptive attachment style, right?

What this means is that if you have

or you develop a secure attachment style,

it’s vitally important to protect that attachment style

because it is possible to become anxiously attached

even if you grew up in a stable attachment framework.

And again, this can happen at any stage.

So if you’re interested in attachment styles

and how they influence adult romantic attachments,

and certainly if you are a parent,

I would encourage you to check out the book, Attached.

Again, it’s quite good.

And I think that it offers a number of actionable tools

to both form and hold on to secure attachment styles.

So I mentioned that the neural circuits

for child parent or child caregiver attachment

are repurposed for romantic attachment later in life.

But what are these neural circuits?

What do they do?

I mean, it’s so attractive, if you will,

to think about a brain area that controls love

or a brain area that controls desire

or a brain area that controls attachment,

but it simply doesn’t work that way.

As I’ve talked about before on this podcast,

and I will say again and again,

because it will persist to be true long after I’m gone,

is that no one brain area can give rise

to anything as complex as desire, love, or attachment.

Instead, there are multiple brain areas

that through their coordinated action

create a sort of a song that we call desire

or a song that we call love

or a song that we call attachment, not a literal song,

although there are songs about desire, love, and attachment,

of course, many songs, some good, some not so good,

but rather different brain areas being active

in different sequences and with different intensities

can make us feel as if we are in the mode

that we call desire or in the mode of love

or in the mode of attachment.

But beneath all of that

is this element of autonomic arousal.

And I want to focus on autonomic arousal

just for a bit longer,

because it really is one of the three core elements

by which we form and maintain loving attachments

and by which we break loving attachments.

The autonomic nervous system, as the name suggests,

is automatic.

In fact, that’s what autonomic means.

Now, it’s actually the case

that we can control our autonomic nervous system

to some degree or another,

but the autonomic nervous system controls things

like digestion, our breathing,

whether or not we’re conscious of that breathing or not,

it controls things like how alert we are

or how sleepy we are.

And the autonomic nervous system,

as I just briefly described earlier,

is really something that we come into the world with,

it’s hardwired, all the elements are there,

but through interactions with our parent,

either soothing interactions or fun, playful interactions,

or dare I say, scary interactions,

our autonomic nervous system gets tuned up,

meaning we each develop a tendency

to either be more alert and anxious or more calm

or kind of a balance of alert and calm.

Now, of course, this changes across each day

and depending how tired we are late in the day,

if we’ve been awake for a while, we tend to get sleepy,

early in the day, if we’re very rested,

we tend to wake up and feel very alert.

So the way to think about the autonomic nervous system

is it’s kind of a seesaw.

We go back and forth between being very alert,

we can be alert and calm, or we can be very, very alert,

we can be in a state of panic, we can be fast asleep,

so we can be extremely calm,

or we can just be kind of sleepy, semi-calm,

but still also alert.

So think about it like a seesaw,

and that seesaw has a hinge,

and that hinge defines how tight or loose that seesaw is,

how readily it can tilt back and forth.

Our autonomic tone is how tight that hinge is,

and there are biological mechanisms to explain this,

but here, I just want to stay with the analogy

of the seesaw for now.

The interactions between child and caregiver early in life

take the child and the caregiver

from one end of the seesaw to the other,

from being very alert in a state of play, for instance,

to being nursed and being very soothed until we go to sleep.

And of course, we each have a seesaw,

the parent and the child has a seesaw,

and they’re interacting.

What do I mean by that?

Well, there are beautiful studies,

and beautiful, not in the sense

that they focused on a pleasant topic,

but beautiful because they were done so beautifully well,

that looked at, for instance,

the response of mothers and their physiologies,

and the response of children and their physiologies

during the bombing of cities during World War II.

So an unpleasant situation,

but what was revealed during the course of these studies

was that if the mothers were very stressed

during an onslaught of bombing of the city,

the children’s physiologies tended to be stressed also,

and persisted in being stressed

long after that stressful episode was done.

They actually followed these children well out

for many decades afterwards.

Conversely, if the parent, and in this case, again,

it was mothers that were explored in these studies,

had turned this whole business

of going into the bomb shelters

into somewhat of a game, right?

Taking it seriously,

but essentially telling the children,

okay, it’s time to go,

but not expressing much stress or distress.

The children also didn’t develop much stress

or distress or trauma.

Now, there were exceptions to this, of course,

but in general, that was the rule

that the autonomic nervous systems of children

tend to mimic the autonomic nervous systems

of the primary caregiver.

And the mechanisms by which this occurs has been explored.

And again, I just referred to the beautiful work

of Alan Shore at University of California, Los Angeles.

And again, his name is Shore, spelled S-C-H-O-R-E.

I’m looking down briefly at the floor here

because I’ll just reach for the book.

He has a wonderful book called Right Brain Psychotherapy.

It’s a little bit technical,

but if you’re interested in some of the studies,

this book, Right Brain Psychotherapy,

details how everything from nursing of children

to playtime behavior to strange situation type task behavior

that we talked about before,

which of course occurs when children get dropped off

at daycare or nursery school or with babysitters, et cetera.

And indeed, all types of caregiver child interactions

tune up that autonomic nervous system

so that the child ends up with an autonomic nervous system

that either tends to lean more towards alert and anxious

or can be very alert but calm

or can be very calm and hard to budge.

Again, it’s the tightness of that hinge

that really underlies these attachment styles

that we were talking about earlier.

And not on this episode of the Huberman Lab podcast,

but on many other previous episodes,

such as the Master Stress episode

or some of the Optimize Health episodes.

You can find these if you want at hubermanlab.com.

A lot of the tools and techniques

that are recommended there

have to do with readjusting the autonomic nervous system

in deliberate ways as an adult.

Again, I won’t go into the specific tools,

but for instance, the physiological psi,

this tool that I’ve talked about extensively

of two inhales through the nose

as deeply as you can on the first one,

sneaking in a little bit more air on the second one,

and then a long exhale through the mouth

is a way of adjusting that autonomic seesaw.

It tends to make us more calm.

It activates what we call the parasympathetic arm

of the autonomic nervous system,

which is just fancy nerd speak

for it’s a quick way to calm yourself down, right?

Things like ice baths or cold showers or cold immersion

or deliberate hyperventilation by contrast

are ways in which we can deliberately increase

the level of our so-called sympathetic

arm of our autonomic nervous system,

make ourselves more alert.

Why would you want to do that?

Well, you can do that to be more alert,

to be more awake if you like,

or as a form of self-induced stress inoculation,

to be able to tolerate higher levels of adrenaline

by making it a practice that you self-direct.

The reason those tools are out there

is because many of us, for whatever reason,

we don’t have to blame anyone,

but because of our childhood templates,

because of things that happened and didn’t happen

in terms of our interactions with caregivers,

have autonomic nervous systems that are tilted

to one side or the other more than we would like,

or in which the hinge that I’m talking about

in this analogy is too loose or that is too tight.

And we’re sort of stuck in a mode of anxiousness

or stuck in a mode of lack of energy.

That’s what those tools are really about.

But at a deeper level,

the autonomic nervous system is really the system

that governs how we will react in response

to a romantic partner being present or leaving.

And I don’t necessarily mean leaving the relationship

entirely, although it could mean that, right?

We know people, I’m sure you know people,

that upon the end of a relationship

that they wanted very much are absolutely crushed.

And actually in researching this episode there,

I discovered there’s an extensive literature finding

that the feelings that one has after a breakup

are very much like a clinical depression in many cases.

But there are individuals that can look at a breakup

as a transient event that they don’t interpret

as going to mean so much for all aspects of their life

or reshaping their view of themselves.

Why?

Well, we have different levels of autonomic function.

And depending on where our seesaw is, if you will,

some of us become extremely distraught

and can’t recalibrate ourselves,

can’t adjust ourselves down from stress to calm,

or can’t take ourselves from exhausted to more alert

if we need to do that on our own.

And so that’s why tools for doing that exist.

But attachment itself is about

where our autonomic nervous system resides.

So if I were to offer a set of tools

around these topics of desire, love, and attachment,

I would say, first of all,

you might want to think about whether or not

you fall into the secure, insecure,

or other attachment styles.

Second, I think it is vitally important for all of us,

but certainly for people that are in relationships

or seeking relationships to be able to

at least have some recognition

of where our autonomic nervous system tends to reside,

both in terms of when we are with somebody

and when they leave.

When we are apart for long periods of time,

can we calm ourselves?

Can we self-soothe?

Or are we very much dependent on the presence of another

in order to feel soothed?

Now, I absolutely want to emphasize

that there is nothing wrong.

In fact, there’s everything right

with feeling great in the presence of somebody else.

That is actually a hallmark

of strong and quality attachments.

These days, we hear the term codependent a lot.

This was a, I believe the term was first coined

by Pia Melody,

and it actually does occupy an important role

in the world of trauma, trauma healing,

so-called trauma bonding, topics of another episode.

I actually did an episode on fear and trauma,

and we will do one all about trauma bonding

with an expert at some point in the future.

But codependence and codependency,

the term can sometimes be misinterpreted

as any dependence on another isn’t good.

Interdependence, healthy interdependence,

of course, is good.

It is the hallmark of healthy child-parent relations,

sibling relations, and romantic relations.

But a key element of healthy interdependence

is that, yes, our autonomic nervous system

is adjusted by the presence of another,

but that also that we can adjust

our own autonomic nervous system

even in the absence of that person,

that if the person goes away temporarily or permanently,

that we can still regulate our own autonomic nervous system,

both from states of stress to states of calm,

both from states of exhaustion to states of more alertness.

And of course, we all need sleep

to go from exhaustion to alertness.

But what I’m referring to here

is the ability to regulate when distraught

or regulate when fatigued or feeling depressed.

And that is and is all about the autonomic nervous system.

So as we talk about attachment styles

and we talk about infant and toddler

and adult attachment styles,

what we are really talking about

is a complex set of neural circuitries.

And one of those neural circuitries,

which is absolutely crucial,

is this autonomic nervous system.

So if the autonomic nervous system

is one key component of desire, love, and attachment,

what are the other two?

And what I’m going to tell you next

is largely the pioneering work of Helen Fisher,

who is really an anthropologist

who’s become a bit of a neuroscientist

and has collaborated with neuroscientists

to establish brain areas and neural circuits

that are associated with different aspects

of attachment, love, and desire.

I think the first really high quality study

of neural circuits associated with these themes

was a paper published in 2005

in a very fine anatomical journal,

perhaps the best neuroanatomical journal,

which is the Journal of Comparative Neurology.

The Journal of Comparative Neurology

has been around for more than 100 years

and is considered the archival location

for placing really high quality anatomy.

They have tremendously high standards.

And the study that I’m referring to

is entitled Romantic Love,

an fMRI, meaning Functional Magnetic Resonance Imaging,

Study of a Neural Mechanism for Mate Choice.

And Dr. Fisher is a author on this paper,

as is Arthur Aaron and Lucy Brown.

So all very fine researchers.

And this study, as well as several other studies

using magnetic resonance imaging,

things like EEG, neuroanatomical tracing, et cetera,

have identified a large number of brain areas

that are associated with different aspects

of desire, love, and attachment.

And I’ll just throw out a few names of those brain areas

and what they control.

And then I’ll tell you how those anchor

to the other two categories of neural circuits

essential for desire, love, and attachment.

So not surprisingly, the dopamine system in the brain

is associated with desire, love, and attachment,

and mainly with desire, although to some extent love.

Dopamine is a neurochemical,

sometimes associated with reward.

But as some of you have heard me say before,

it is mainly a molecule of motivation, craving, and pursuit.

And that motivation, craving, and pursuit

that relates to dopamine is not unique to attachment

or love or sex or mating, et cetera.

It is a universal generic currency in the brain

for pursuing something.

Food when you’re hungry, a mate when you want one,

to mate when you want to, warmth when you’re cold,

et cetera, et cetera, okay?

So it’s not for one specific purpose,

but the brain areas associated with dopamine involve,

for instance, the ventral tegmental area,

the substantia nigra, areas of that sort,

the basal ganglia.

You don’t need to know these names.

Just understand that these are networks of neurons

that tend to put the person, you,

into a state of forward action and pursuit

and craving and motivation.

They are not about being quiescent, relaxed, et cetera.

The neural circuits for quiescence and relaxation

are most associated with love and attachment,

not surprisingly.

And they’re the neurochemical serotonin,

and to some extent, oxytocin

are the predominant neurochemicals involved.

And those are released from brain areas

such as the raphe nucleus in the back of the brain.

You may have heard that the majority of serotonin

in your body is made in your gut.

And indeed that’s true, but I hate to break it to you.

The serotonin in your gut is not responsible

for your feelings of love and attachment,

at least not to a high degree.

That’s mainly going to be the reflection of neurons

in your brain that make serotonin.

And there are other areas of the brain

that make serotonin as well, and oxytocin as well,

but they tend to be associated

with the kind of warmth and calm

and the soothing that we feel in the presence of another.

And again, these are not strictly divided circuits.

We can have dopamine and serotonin

present in our brain and body at the same time

to equal or different degrees.

And we will return in a little bit to what happens

when levels of dopamine are very high

and levels of serotonin are low and vice versa and so on,

including in states of neurochemically modified states,

as it were, in when we talk about things like MDMA,

so-called ecstasy.

But in the meantime, I want to just discuss

the two neural circuits that use dopamine,

that use serotonin and oxytocin,

and that collaborate with the autonomic nervous system

to drive what we call desire, love, and attachment.

And the three circuits are autonomic nervous system,

we talked about that one.

Then there’s the nervous system components

or the neural circuits for empathy,

for being able to see and respond to

and indeed match the emotional tone

or the autonomic tone of another.

And then there’s the third category,

and this might surprise some of you,

it certainly surprised me,

but the data point to the fact that the third neural circuit

that’s very important for establishing bonds

is one associated with positive delusions.

So given that the neural circuits for empathy

are absolutely crucial for falling in love

and maintaining stable attachments,

I’d like to talk about those neural circuits

and what they are.

Now, often when we hear empathy,

we think, oh, empathy is really about listening to

and really understanding what somebody else is feeling,

maybe even feeling what they’re feeling.

And indeed that’s the case,

but what do we mean by that, right?

What is it to feel what another feels?

Well, what it means is that their seesaw

is driving your seesaw

or your seesaw is somehow driving their seesaw,

that there’s a match in terms of the tilt of those seesaws.

Now, it doesn’t have to be an exact match, right?

If someone that you really care about is very, very stressed

you could also become very stressed,

that’s a form of empathic matching.

And there are indeed neural circuits for that,

I’ll describe what those neural circuits are in a moment.

But sometimes the best role for us to take

is actually one in which we are calm

when the person that we care about

or that we are romantically involved with

is very, very anxious.

And in a few minutes,

I’ll talk about how matching of emotional tone

can be good or bad for the stability of a relationship.

And complementarity of autonomic matching

can be good or bad.

In other words, sometimes it’s beneficial

for a relationship to go into the same state as the other.

And sometimes it’s more beneficial for us

to not go into the same state as the other.

But the important feature here

is that when we talk about emotional matching or empathy

or going into the same state

or not going into the same state,

what we’re really talking about

is whether or not the autonomic seesaw of one individual

is driving the autonomic seesaw of the other individual.

And this is a vital principle

for how we fall in love and form attachments.

And it’s actually part of the desire

and mating process itself.

I would go so far as to say

that one of the prerequisites

to the propagation and expansion of our species

is this notion of autonomic regulation

and to some extent matching of autonomic nervous systems.

Let me explain what I mean.

Last I checked,

the only way that new humans can be created

is by way of sperm meeting egg,

either in body or in dish,

but sperm meets egg.

And then typically nine months later, we have a human baby.

The process of bringing sperm to egg, right?

Mating behavior, sex behavior in humans

is one of autonomic regulation.

And what I mean by that

is the process of finding a mate.

And in this case,

I mean actually someone to mate with typically,

while scenarios vary,

typically is one of elevated autonomic arousal,

meaning increased activation

of the so-called sympathetic nervous system.

This is related to dopamine release

and it’s related to epinephrine release.

There has to be a pursuit

or at least there has to be a mobilization

to arrive in the same location whereby one can mate, right?

That almost always is the case.

However, the sexual arousal itself

is in both males and females

is actually driven primarily

by the parasympathetic arm of the autonomic nervous system.

So while pursuit is one of alertness

and sympathetic drive, as we say,

again, sympathy is not really what’s at play here.

The word simpa means together

and the activation of the autonomic nervous system

toward more alert state

is because of a sympathetic nervous system,

meaning the co-activation together of many neurons

in the brain and spinal cord.

But then the actual physiological arousal state

that we call sexual arousal

is predominantly parasympathetically driven, okay?

To be quite direct about this,

if the sympathetic nervous system activation is too high,

the sexual arousal response cannot happen

in either males or in females, it’s inhibited.

However, the orgasm and ejaculation response,

which if you think about it is required

for sperm to meet egg is sympathetic driven.

And then after orgasm and ejaculation,

the parasympathetic nervous system kicks back in

and there’s a calming and relaxation.

So the arc of mating involves sympathetic arousal, okay?

Not sympathy, but alertness and arousal for pursuit.

Then a tilt of the seesaw, at least to some degree

for arousal of the sort that we typically hear of,

of sexual arousal.

Then at the point of orgasm and ejaculation

is back to a sympathetic response.

And how can I say that?

How do I know that?

The sympathetic nervous system,

meaning neurons within the sympathetic arm

or the autonomic nervous system

are what drive ejaculation and orgasm.

And then afterward, there’s a return

to increased parasympathetic activation.

And we don’t know for sure why that happens,

but it’s thought that in species that pair bond,

humans generally pair bond, not always,

the return to more parasympathetic activation

after orgasm and ejaculation

is thought to increase the exchange of pheromonal odors

and to increase pillow talk

and pair bonding of different kinds, okay?

So that’s the seesaw going back and forth

is actually built into the process

by which our entire species propagates.

So in some ways, every human is required

to navigate that process

if they want their offspring to persist.

And of course, nowadays there are technologies

like in vitro fertilization, intrauterine insemination.

There are a variety of ways that technology

has allowed people to circumvent

the actual physical mating process

in the way that I described.

But by and large, that’s the way it’s done.

And certainly that’s the way it was done historically

for if not tens of thousands

or hundreds of thousands of years.

That process is also what happens

in all mammalian species that mate, okay?

So I’m overlooking an entire literature of animal studies

that classic studies of this were done by two individuals.

I’ll just briefly mention them

in case you want to look at the literature.

There’s a guy at the Rockefeller University

named Donald Pfaff, P-F-A-F-F,

who has done beautiful studies

identifying the neural circuitry

of what’s called the lordosis response.

Unlike in humans, the mating behavior of animals

is rather stereotyped in terms of the positions

that they occupy.

And the lordosis response is a kind of a U-shaping

or a bending up of the hindquarters of typically of rodents,

but of other animals as well.

The male mounting is almost always from behind

except in some species of primates.

And that lordosis response is only going to occur

during particular phases of the estrous cycle.

The estrous cycle is sort of the analog

to the menstrual cycle, but it’s not 28 days,

it’s four days or some other duration in other animals,

depending on the animal.

The lordosis response is strongly regulated by odors,

by contact, and is estrogen and testosterone controlled.

And then the male portion of the mating sequence in animals,

the mounting and thrusting and ejaculation

as they’re called are mounting, thrusting, intromission,

and ejaculation.

Those are the four scientific categories

that have been described.

That’s presence in rodents and also in dogs

where it was primarily studied by Frank Beach,

who was at University of California, Berkeley

for a long time.

And the entire literature around the neural circuitry

for sexual and mating behavior in animals largely stemmed

from the work of Donald Pfaff and Frank Beach

and their scientific offspring,

not their actual offspring.

You can look at that literature if you like.

There have been human neuroimaging studies

of the process that I described a few minutes ago,

believe it or not, of people in brain scanners,

not necessarily mating with other people,

but going through that arc of arousal,

sympathetic activation during orgasm or ejaculation,

and then the post ejaculatory or orgasmic phase

in both men and women.

And the brain areas associated with those

have all been mapped out now.

The spinal cord areas that control things like erection,

vaginal lubrication, ejaculation, and orgasm,

those have also been mapped out.

And this has all been explored from the perspective

of both basic science, just to get an understanding

of how our species has sexual interactions and reproduces,

but also from the perspective of, for instance,

trying to repair sexual function after spinal cord injury,

which is a prominent concern for a lot of people,

depending on where they have their injury,

but in the number of people that have spinal cord injuries.

So this is both vital biological and clinical data.

The neural circuits for everything that I just described

reside in the autonomic nervous system

and are coordinated with the neural circuits

that are associated with empathy.

The neural circuits for empathy, again, there are many,

but mainly two structures that you should know about,

the prefrontal cortex,

which is how we perceive things outside of us

and make decisions on the basis of those perceptions,

how we organize those decisions,

and an area of the brain called the insula, I-N-S-U-L-A.

The insula is a really interesting brain area

that allows us to interocept,

to pay attention to what’s going on inside our body,

and to split some of our attention to exterocept.

And the mating dance,

whether or not it’s the dinner and date portion

of the mating dance,

or the actual physical dance part of the mating dance,

or actual mating and sexual behavior,

kissing or otherwise,

that is a coordinated activity of two bodies.

Typically it’s two.

I realize sometimes it’s more, sometimes it’s only one,

but typically it’s two bodies,

at least in the framework we’re using here.

That coordinated dance is one in which

the autonomic nervous system of one individual in general

is coordinating with the autonomic nervous system

of the other individual,

and the insula is essentially splitting one’s attention

between how we feel ourselves,

how our body feels, what we’re thinking,

with the thinking and the bodily sensations of the other.

And that can be communicated obviously through words,

it can be communicated through sounds,

it can be communicated through touch,

and it can be communicated through a number

of kind of more subtle cues like pupil size,

or whether or not,

certainly in cases where we recognize the person

and we kind of know their responses,

their autonomic responses under different conditions,

we can assess, is the person comfortable?

Are they uncomfortable?

Are they more focused on me or on themselves?

This is the coordinated silent dance

that if we look at in neurobiological terms,

we can really see is all about the autonomic nervous system,

whether or not it’s time to tip the seesaw

to one side or the other,

depending on whether or not the other person’s seesaw

is tilted higher or lower than the other.

Okay, so we have the autonomic nervous system,

and then we have this thing that we’re calling empathy,

which is really about autonomic matching.

And again, the insula and the prefrontal cortex

are neural circuits that are crucial for autonomic matching,

because they allow us to say what’s out there

and do I want to match to it or not, okay?

And then the third category of neural circuit

that Helen Fisher and others have found to be important

for desire, love, and attachment

is the neural circuit associated with self-delusion.

What do we mean by that?

Well, first of all, self-delusion implies a kind of cynicism

about love and attachment.

And I think it was George Bernard Shaw that said,

love is really about overestimating

the differences between individuals.

Actually, when I hear that, and as I say it,

I really don’t like that quote.

I have no bone to pick with George Bernard Shaw,

but what it suggests, and I think what he meant

was that in love and attachment,

we tend to put so much value in the other

that we forget that many of the processes

that are going on in our brain and body

actually could be evoked by many other people too.

But I think it somewhat overlooks

the enormous power of attachment

and the ways in which somebody’s smell,

somebody’s voice, somebody’s everything,

or somebody’s particular thing or things

can really become so vital

for our autonomic nervous system to feel soothed

and to feel elated, et cetera.

So I think that while the quote is accurate in the one sense,

I think it does overlook the neural circuits for attachment

and just how deeply wired those can become for us.

So I will balance that quote

with an enormous number of other quotes

that I won’t mention, but that you can find out there

that really point to how incredible the person is

that one tends to be attached to,

that there’s really only one or several people

that could ever exist

that could evoke those feelings from us.

And of course you can read your Neruda poetry

and you can find these things all over the place

in music and poetry and writing.

So for every cynical quote

about these neural circuits being generic

could be activated by anybody,

I think you’ll find an ample number of opposing quotes

that these neural circuits can only be activated

by that special someone or that particular person

or maybe in just a small set of those people.

So what of delusion?

Well, the work of Helen Fisher and others

has really pointed to the fact that desire, love,

and attachment are three separate phases

of what we call romantic relationships

that typically, not always,

but typically desire tends to come first

or falls in the early phase,

that the process of romantic slash sexual interactions,

it doesn’t necessarily have to be sex itself,

but certainly something that involves intimacy of some kind

and generally touch of some kind

eventually transitions into what we call love,

which eventually transitions into what we call attachment.

And I should just mention touch

because touch is a fundamental aspect of this whole process.

There’s an article, a research article, I should say,

the title of it is

Relationship-Specific Encoding of Social Touch

in Somatosensory and Insular Cortices,

cortices being cortex, cortex is plural, cortices.

And again, there’s our friend, the insula.

So this is a study that explored what brain areas

and what body areas are activated

by specific forms of attachment and social touch.

And what they found, not surprisingly,

is that the areas of the brain

that are associated with touch, the somatosensory areas,

but more interestingly,

the insula cortex are strongly activated by touch.

So touch and the amount of touching

and proximity and skin contact,

not surprisingly activates brain areas

associated with somatosensory touch,

but also the insular cortex,

which again is this brain area that links the internal,

our feelings about what’s going on inside us

and at the surface of our skin with events external.

And they found activation of a number of brain areas,

the amygdala, orbitofrontal cortex, and so on and so on.

That’s not as essential as just understanding

that the insula is the place in which we start

to take our experience of our internal landscape,

attach that to our perceptions of the external landscape,

and then assign that a value

or assign that some sort of interpretation.

And positive delusion is predictive

of long-term attachment.

What do we mean by positive delusion?

Positive delusion is the contradiction

of that George Bernard Shaw quote.

It’s the belief that only this person

can make me feel this way.

This other person holds the capacity

to make me feel this way physically

or emotionally or both.

And so as we move from desire to love to attachment,

our brain circuitry is literally getting tuned up

such that that individual that we happen to be attached to,

again, here thinking about monogamous relationships,

but I guess for non-monogamous relationship,

it’d be individuals, is and are the way

in which our autonomic nervous system can be regulated.

They actually get access to our control panel.

So it’s our autonomic nervous system, empathy,

and this positive delusion.

Now, positive delusion is critical.

If you look at the stability of relationships over time,

something that’s been extensively studied

mainly by psychologists, but now also by neurobiologists,

what you find is that there are some key features

of interactions between individuals

that predict that a relationship will last.

And those are many, but mainly fall

under this category of positive delusions.

I’ll return to those and what those exactly look like,

but there are also just a handful of things

that predict that a relationship will fail over time.

This is largely the work of the Gottmans.

It’s actually a husband and wife team

up at the University of Washington in Seattle.

The Gottmans have run a laboratory

in the department of psychology for a long time.

They’ve also done a lot of public facing work

around relationships.

And they’ve talked about the various aspects

of relationships and interactions between people

that predict either staying together or breaking up.

So much so that they’ve established a method

by which they can look at video interactions

between couples and with very high degree of certainty,

predict whether or not those couples will stay together

or break up over time.

And they’ve identified what they call

the four horsemen of relationships.

These are things that essentially almost always predict

that a couple will break up.

And I think the current number on this

is that Gottman can predict divorce with 94% accuracy,

which if you think about it is pretty remarkable.

So even though these are purely psychological studies,

I’m not aware of any analysis of underlying physiology.

There are some things that they can observe between couples

that can lead them to predict

whether or not a couple will stay together

or break up with 94% accuracy.

So what are those things?

Those four behaviors,

what they call the four horsemen of the apocalypse

for relationships are one, criticism,

two, defensiveness, three, stonewalling,

and four, contempt.

With contempt being the most powerful predictor

of breaking up.

Criticism, of course, does not mean

that there’s no place for criticism

in stable relationships.

Of course there is.

It has to do with how frequent

and how intensely that criticism is voiced.

Defensiveness, of course, is defensiveness.

We know as the sort of lack of ability to hear another

or to adopt their stance.

So lack of empathy, I think,

is one way to interpret defensiveness.

Stonewalling, which is actually another form

of lack of empathy.

It’s a turning off of this neural circuit

that’s so critical for desire, love, and attachment.

The stonewalling essentially means the emotional response

or the request of another is completely cut off.

So I don’t think there’s been brain imaging of this,

but I think we can reasonably imagine

that it involves untethering your insular response

from the other and what they’re dealing with

and focusing your insular response, no pun intended,

on your own internal state

or perhaps the state of someone else entirely.

We’ll talk about infidelity in a moment.

And then contempt.

And contempt has actually been referred to

as the sulfuric acid of relationship.

I didn’t say that, but Gottman and colleagues have,

that it is such a powerful predictor

of divorce and breakups in the future.

And contempt, of course, by definition,

is the feeling that a person or thing

is beneath consideration, worthlessness,

or deserving scorn.

And apparently they can identify this

in the videos of couples having discussions

and interacting by very elaborate eye rolls,

by expressions of anger in one individual

when their partner is actually expressing enthusiasm

or excitement about something.

It’s the, oh yeah, you would say that,

or deep-seated resentment toward the other,

so much so that it’s apparent

that one kind of actively dislikes the other partner.

So contempt, disregard for something

that should be taken into account

is the other way to think about it,

runs counter to all of the neural circuits,

all three of the neural circuits

that we talked about before.

It certainly is, it is the antithesis of empathy.

It is anything but a positive delusion.

It’s really looking at the other individual

either accurately or inaccurately

as somebody that you kind of despise.

And then it is an absolute inversion

of the autonomic seesaw matching

that I was talking about before.

It’s a dissociating of your seesaw from their seesaw.

They’re very excited about something,

you’re unexcited by it.

In fact, it’s an inversion of their seesaw

where they’re excited, you’re down.

They’re down, you’re up, okay?

So it’s basically an inversion of all of the neural circuits

that Helen Fisher and others have identified

as critical for desire, love, and attachment.

And therefore it’s not surprising

that it is so strongly predictive of breakups

and in the case of married couples of divorce.

For those of you that are interested

in the work of the Gottmans and similar work,

they’ve written several popular books.

They’re fairly easy to find.

We can link to one of those in the caption,

but they’ve also developed

some quite interesting online resources

in their so-called love lab.

I guess it’s fortunate that they didn’t call it

the hate lab or the breakup lab

because they focused a lot on what predicts breakups,

but they’ve also written extensively

and researched extensively in peer-reviewed studies

what makes people find appropriate partners for them

and to maintain those partnerships over time.

So you can go, you can search for love lab,

University of Washington, Gottman,

or any number of their various books.

I think you’ll find some useful resources there.

I want to shift back to the work of Helen Fisher.

She’s made some very interesting statements

and some very interesting observations

that at least to my mind,

map very well onto the knowledge of neural circuitry,

both in humans and in non-human primates

and in other species.

I realized that she’s not the only name in the game,

but she’s made some observations

that I think are very, as we say, parsimonious,

meaning they allow us to organize a lot of this stuff

into some distinct frameworks.

She’s also done some really beautiful studies

that involve data from millions

or even tens of millions of individuals on dating sites.

So I’m going to share those with you in a moment.

But before I do that,

I just want to paraphrase Dr. Fisher,

who said that sex drive or desire,

the pursuit of someone to mate with,

meaning to mate the verb, not necessarily to find a mate,

may be, she didn’t say definitively,

but maybe a way to forage for potential love partners,

that the arc of this whole business

is really the order that we’re describing it,

that it’s desire, then love, and then attachment.

And that oftentimes people can get confused.

You may know some of these people,

you may be one of these individuals

who might confuse desire for attachment

or might confuse love for attachment,

but that there’s a sequence of recruitment

of these neural circuits that’s established first

from the pursuit of someone to mate with.

And she’s placed us in the context

of kind of more modern dating themes

where depending on culture,

people might explore several, maybe many, many individuals

before, quote unquote, settling down with somebody,

at least for some period of time.

I think that’s an interesting framework

because it circumvents a lot of the, frankly,

unanswerable questions about whether or not,

you know, humans were meant to be monogamous

or whether or not they weren’t.

Those are conversations that hold cultural context,

that hold all sorts of context

that really can’t be addressed in a laboratory setting.

But this idea that sex drive is a way to forage

for potential love partners,

and that love is a kind of a litmus test

for whether or not longer term

or deeper attachments can and will form

is one that at least makes sense to me.

Later in the episode,

we’ll talk about this notion of sex drive and desire.

I’ll actually talk about some tools

that have very strong data really to support them

in terms of things that people can do or take

to increase libido, both men and women,

because there’s actually quite good data on that now.

But in the meantime,

I want to talk about some of the work

that Dr. Fisher has done in terms of categorizing people

into, again, we have four groups.

These are distinct from the A, B, C, and D

attachment styles described earlier.

Although as I described them,

you might be able to map them somewhat onto those.

And these four groups are groups

that were defined through her studies

of people that were, or are,

I don’t know if they were,

or if they are still on match.com,

but a very extensive data set.

So again, millions,

if not tens of millions of individuals.

The number, I heard her quote,

and forgive me if this is not accurate,

is that in upwards of 40 million individuals,

in terms of whether or not their neurochemical

and hormone systems are tuned

toward particular types of behaviors.

What do I mean by that?

Well, both men and women, males and females,

have both testosterone and estrogen.

Typically, again, these are averages,

but typically men have more testosterone

than they do estrogen,

and they have more testosterone than do women,

and less estrogen than do women.

Typically women have more estrogen

than they do testosterone.

Again, averages.

And they have less testosterone than men,

more estrogen than men,

and so on and so forth.

But both hormone systems are active

in both sets of individuals.

And of course, all humans, as far as we know,

manufacture both dopamine and serotonin.

Dopamine, as I mentioned earlier,

has a number of effects in the brain and body,

but one of the primary effects

is that it places us into states of motivation and pursuit.

There is a somewhat close relationship

between the dopamine system

and the testosterone system in the hypothalamus,

this brain area above the roof of your mouth,

and the pituitary gland,

which is responsible for making hormones

that make the ovaries and or testes

secrete testosterone or estrogen.

So there’s a lot of signaling that occurs

such that dopamine and testosterone

tend to operate as kind of close cousins

in a system of pursuit.

And conversely, the serotonin system

tends to, on average, collaborate with the estrogen system

to impart certain physiological functions and behaviors.

So these aren’t hard and fast,

or I guess better stated,

these aren’t strict black and white categorizations,

but I think those general themes hold

when you look at the animal and human data.

So Dr. Fisher has taken some liberties,

but I think they are what I would call

logically and scientifically

and neurobiologically grounded liberties

in classifying individuals who are on these dating sites

according to the types of things they report

about themselves and the type of people

they tend to match with on these dating sites

and created these four categories.

The four categories are,

she calls one the dopamine category.

So these are people who would have high dopamine.

And again, that’s just a name.

It doesn’t mean they have low anything else,

but they are high on the dopamine scale.

People who rate high on the dopamine scale

tend to be what the scientists and psychologists

call high sensation seeking, novel seeking.

They like new things.

They like spontaneity.

They tend to be very adventurous.

And I think that’s largely true.

If you look at conditions

where dopamine is super physiological,

it’s elevated beyond normal levels,

things like mania,

or when people take certain drugs of abuse

like cocaine or amphetamine

that really raise dopamine levels up very, very high

for some period of time,

they do tend to increase energy motivation

and novelty seeking.

And of course, drugs like amphetamine and cocaine

have all sorts of deleterious effects

that I don’t need to go into here,

but it’s worth pointing out.

But they don’t tend to make people calm and relaxed

and seek soothing interactions.

Conversely, the group that Dr. Fisher calls

the serotonin group

tend to be more grounded in soothing activities,

quiescent type activities.

They actually tend to be on average,

they tend to like rules and follow rules.

They tend to be homebodies, this sort of thing.

They’re really, you can imagine them

the sort of stable types,

but they really like stability.

They’re not really into spontaneity as much, again, averages.

And then she created two other categories,

the testosterone category of high testosterone.

This again, could be males or females.

And then the estrogen category,

again, could be males or females.

And she gave these different names

that I won’t go into here.

You can look up her work online,

but names like the director

and the follower and things like that.

But I don’t really want to use those

as much as I want to stick to the biological terms.

So we have dopamine, serotonin, testosterone, and estrogen.

Now that might seem like an unfair

kind of over-generalization,

but what’s interesting is not necessarily

the name or the neurochemical system, right?

Those could have just been called

category one, two, three, and four

for all that matters here.

What is interesting is seeing

how those different groups of individuals

that she absolutely can categorize

based on their self-reported preferences

about behaviors and certain kinds of interactions,

how those groups tend to pair up

with people in the same or opposite categories.

So what her studies reveal

is that people that fall into the high sensation seeking,

novelty seeking, spontaneity category,

the one that she calls the high dopamine category,

tend to pair up with, at least in the short term,

tend to pair up with people

who are also in that dopaminergic category.

So these would be people

that would spontaneously take a trip

or explore something new or a new restaurant.

They tend to be creative and explorative types.

So that group, on average,

tends to date and mate

and potentially form long-term relationships

within category, again, averages.

Individuals that she placed into the serotonin group

or what she hypothesized would be a high serotonin group,

again, they didn’t measure serotonin,

but people that tend to place value on stability,

on rules, on certain forms of kind of traditional

organization at home and in relationships,

those people also tended to pair up with select date,

we presume mate with,

and form stable relationships

with people in the same category.

Now, individuals in the other two categories,

the high testosterone group,

and again, testosterone wasn’t measured,

but she called it the high testosterone group.

But these are people that tend to be very directive.

They tend to know what they want

and are comfortable telling other people

what they want and from them.

These are individuals that in her studies

and in other studies tend to be a little bit challenging,

meaning they, not necessarily challenging to be around,

but they tend to challenge other people,

kind of push them in order to expand their boundaries,

either for sake of the relationship or just in general.

And the people they tend to push

are the people that they pair up with,

which are the people in the estrogen category,

what she called high estrogen.

Again, they didn’t measure estrogen,

but the people in the estrogen category

were the ones that describe themselves

and their choices in life

and their preferences as being nurturing.

They actually seem to like it when someone else

is making the major decisions,

not every decision.

They certainly like to be heard, of course,

in terms of their preferences,

but that those two types,

what she called the testosterone and the estrogen type

tend to pair up.

So why are these categorizations

and these averages interesting to me,

at least interesting enough to convey to you?

The reason they’re interesting to me is,

again, not because of their names,

these molecules were not measured in these individuals,

but that they once again bring us

to the themes that we addressed before,

which are the autonomic nervous system

and whether or not it tends to be shifted

more towards alertness in action

or more towards kind of a stable equilibrium

or more towards kind of calm

and whether or not individuals are selecting

for people who have autonomic nervous systems

that are more or less like theirs

before they even meet, right?

So again, going back to this seesaw analogy,

it’s almost like people who have the kind of flat seesaw,

alert but calm, but not extremely alert,

not extremely overly calm in situations,

but kind of in the middle,

seem to be seeking out people that are also

at that kind of autonomic equilibrium.

People in the, what she called the dopamine category,

which really can just be described

as high sensation seeking, novelty seeking,

they seem to want to pair with one another.

So there’s a selection for similar in two of the groups,

autonomic tone.

I find that very interesting because in that decision

or that preference for similar autonomic tone,

it essentially eliminates a lot of the requirement

for figuring out how to match

one’s autonomic nervous system to another.

They simply find someone with a similar tendency, okay?

Whereas in the other two groups

that she called testosterone and estrogen,

the director type and the nurturing kind of

somewhat follower type,

there’s an establishment of balance,

but not between two individuals as a match,

but rather on the whole in the relationship.

One person is kind of driving the novelty seeking

in the course of decisions and actions.

And the other person is essentially agreeing to those.

Now, assuming that those decisions are good for both people.

And I emphasize good for both people

because one of the themes that Dr. Fisher underscores,

and I’d like to underscore here as well,

is that it need not be the case that people pair up

exactly according to these categorizations

that I’ve described.

Dopamine with dopamine, serotonin with serotonin,

testosterone with estrogen, and so on.

What is important is that there be a recognition

and a respect for the other types

or a recognition and a respect for the fact

that both are of the same type.

You could actually imagine, for instance,

that two people of this high sensation seeking,

novelty seeking could have

a terrifically exciting relationship,

but that it actually might be a relationship

in which the financial stability isn’t quite there

or in which the basic stability isn’t there.

You could imagine, for instance,

a situation in which a relationship between two people

of what she called the high serotonin preference

would have a relationship that was actually kind of dull

in which both of them found themselves

kind of bored at some point,

or in which there wasn’t enough of the dynamic tension

that sometimes is required in order to keep this cycle

of desire, love, and attachment going,

something that we will talk about in a moment.

So the point here is not that one should necessarily pair up

according to these arrangements that I described.

The point is that on average, that’s what tends to happen.

And that through a recognition

that these categorizations exist,

similar to the recognition that the type A, B, C, and D

infant and toddler type attachments exist,

that we can gain better self-awareness of who we are

and how we tend to show up in romantic attachments

and thereby navigate healthier mate seeking,

healthier breakups, if the case dictates it,

and in some cases, healthy long-term relationships

by understanding that the other person

can either be similar or complimentary to us.

One is neither better than the other.

It’s simply the case that in all romantic attachments

from the initial inception of the romantic attachment,

desire, love, and attachment,

there is an autonomic coordination.

And of course there’s coordination

of all sorts of other things like, you know,

food, sex, and sleep, and finances,

and where people are going to live and many other features,

but that at the core of all that

is a seeking of either autonomic likeness

or autonomic differences.

And I think that recognition can be extremely valuable

in thinking about tools to enter

and maintain relationships.

If one thinks about their autonomic nervous system,

not simply as something that is driven

by external people and events,

but that we can actually gain some control over

through techniques of the sort that I talked about earlier

and on previous podcasts, but also generally,

if we are able to adjust our autonomic nervous system

in order to at least appreciate or get some empathy

into what someone else is experiencing,

then we gain actual cognitive empathy.

And this episode isn’t about empathy per se,

but the theme keeps coming up again and again.

And I think it’s worth mentioning

that when you talk to psychologists,

whether or not they’re psychoanalysts

or from another source of training,

what you find is that they don’t talk about empathy

as a general term, they will talk about emotional empathy.

They’ll talk about cognitive empathy.

And what I’m talking about here today

is that yet a third category that is very strongly

determinant of relationship dynamics,

and that’s autonomic empathy.

I’m a biologist, I’m not a psychologist,

so I love mechanism.

And fortunately, there are studies that have been done

recently using modern techniques

to look at neural mechanisms of romantic attachment.

I mentioned earlier some of the brain imaging studies

that have been done on child and mother,

literally imaging the activity of neurons in the brain

as child is nursing or as a mother is soothing baby.

And as you learned earlier,

baby is soothing mother as well.

Those are remarkable studies.

You may have seen some of these pictures online.

You can see the kind of silhouette of the infant and mother

and their brains,

and even some of the brain activation patterns,

really, really beautiful studies.

Similar studies have been done in romantic couples

with those couples either touching one another,

touching and kissing, or in kind of clever,

I think control experiments of the person

just touching a pillow or something or kissing a pillow

in order to try and create the most reasonable control

for what are actually pretty complicated

interpersonal dynamics to do in a brain imaging scanner.

But some of the other studies that have been done recently

involved so-called EEG.

So these are electrical recordings

that are done non-invasively,

putting a bunch of electrodes on the outside of the scalp.

EEG is useful in that you can do it non-invasively.

You can do it while people are moving and doing things,

kissing, touching, et cetera.

It doesn’t allow one to image

or to evaluate neural activity very deeply in the brain.

So you can miss out on a lot of things.

It’s sort of like looking at the wave structure on the ocean

without actually looking into the depths of the ocean.

So you can miss certain things,

but if you see things generally you trust they are there,

but you can’t see what you don’t see.

Nonetheless, there’s some studies that I’ll just point you

to and that formed the segue

for what I’m going to discuss in a moment,

which is a study published in Scientific Reports in 2021

entitled Investigating Real-Life Emotions

in Romantic Couples, a Mobile EEG Study.

So this is as the title suggests,

having people wear these EEG caps of electrodes,

get engaged in very passionate emotional kisses,

emotional speech toward one another,

standing at different distances.

So a lot of cool stuff that you can do

that you really couldn’t do in a brain scanner

because in a brain scanner,

people have to be there in a, usually in a bite bar.

They’re actually to draw like this.

I’ve been in one of these things.

There’s not a lot of moving around to be had,

at least not using the current technology.

In any case, what they found was

there is a shift in brain waves, brain states,

things like alpha waves,

which is a particular frequency of brain waves

in the neocortex,

the kind of outer shell of the brain just beneath the skull.

And in people that are kissing

or in people that are engaged in romantic speech,

or I didn’t actually hear what they said to one another,

but what the couple seems exciting,

romantic and arousing to them,

they see more alpha wave activity

compared to the control conditions.

And there was some, what we call lateralization,

where the left hemisphere was more active than the right

and so forth.

And these studies are important

because we know that the autonomic nervous systems

of individuals tend to start to collaborate

and actually synchronize at the level of heartbeats,

at the level of breathing

during romantic interactions of different kinds.

But these studies are some of the first of their kind

to start looking at neural synchronization

between individuals.

Now, the simple version of looking at this

and the way I would have thought this would all go was,

okay, two people start kissing,

they start talking about what they find

particularly romantic and arousing for them,

and their brain waves will just match to one another.

And that’s really the basis of romantic attachment

and romantic engagement in that sort of thing.

But it turns out that the opposite is true.

So a really nice study published in a really fine journal,

Cerebral Cortex is a journal

that I’ve known about for many years.

They publish strong anatomy, physiology, and neuroimaging.

There’s a study that was published,

first author Kajimura in,

and this paper really points, again, this is 2021.

And the title of this paper is

brain knows who is on the same wavelength.

Resting state connectivity can predict compatibility

of female-male relationship.

Now, what this study did was a little bit different.

They looked at the resting

or default mode activity of the brain.

So rather than evoked activity, as it’s called,

where people are kissing

or engaged in some sort of activity,

this was a neuroimaging study, not EEG,

but fMRI, functional magnetic resonance imaging,

which is similar to EEG in principle,

but allows you to look deep into the brain.

And it has very good resolution in time and space.

So fast events can be monitored,

and the precise location of those events can be monitored

somewhat better than EEG.

There are exceptions to this.

So for you EEGers out there,

EEG, don’t come after me with electrodes.

Just understand that fMRI gives you a fuller picture

of what’s going on.

And what Kajimura et al found was that contrary

to what your reflexive prediction might be,

people tend to select people that have resting brain states

that are different than theirs,

or sometimes they found that are actually opposite

to their own resting brain state.

And you might say, well, that doesn’t make any sense.

I thought this is all about autonomic coordination.

But actually, if we go back to Helen Fisher’s

categorizations of the dopamine types,

the sensation-seeking types, that is serotonin,

the kind of stable rule-following types,

testosterone and estrogen types,

remember that the two categories

that she called testosterone and estrogen type,

the director and the follower, the nurturer,

I guess it would be the more accurate way,

the director and the nurturer,

those tend to pair up across categories,

not within category.

And so I think what’s really needed for this field,

which to my knowledge hasn’t happened yet,

is to really start to map the neuroanatomical

and neurophysiological findings of, in this case,

that resting brain state is in one form, in one individual,

and they tend to seek out people whose resting brain state

is different than theirs, not similar.

That needs to be mapped onto the more subjective,

psychological categorizations that Helen Fisher

and indeed the Gottmans and others have created.

That’s sort of the state of the field now.

And I mentioned this, not to confuse you,

but to the contrary, to illustrate that it’s not just

about finding someone just like you.

And it’s not just about finding someone

who’s opposite to you.

This is actually the reason that I decided to become

a biologist at some point in my life,

which is that we can find verbal sayings and stories

and examples to support just about anything.

This is not a knock on the field of psychology,

as you can probably tell from today’s episode,

I have great respect for and reverence

for the field of psychology,

especially its collaboration with neuroscience

and vice versa.

But in the popular culture, we can find examples

and sayings that support essentially anything

as it relates to a relationship.

For instance, I’ve heard, and you’ve probably heard,

absence makes the heart grow fonder.

And indeed I’ve experienced that, and I believe it’s true.

But I also have experienced, and I believe to be true,

that out of sight, out of mind also exists

and that there will be a biological mechanism for that.

The point here is that matching of same to same

or same to different can both be effective

in creating the desire love attachment process.

It’s a matter of who is looking for same

and who is looking for different.

And there, I think Dr. Fisher

and the work of these neurophysiologists

and brain imagers really does point in a direction

whereby there is not one form of attachment

that is going to be wholly above all else

and will predict good outcomes.

There is not going to be a case in which opposites attract,

and that’s always the best rule to follow.

Sometimes it will, sometimes it won’t.

There is also not the case that people tend

to pair up with similar.

Sometimes it will be the case.

Sometimes it won’t.

Now, there are certain statistics

that support that statement.

For instance, people on average,

people pair up with individuals

of similar educational background, income and attractiveness.

That is true on average, but it’s not always the case.

And again, a knowledge of and a respect

for the different categorizations of attachment,

the different categorizations of mate seeking

described by Fisher and others,

and the recognition that matching

of autonomic nervous systems,

but also mismatching of resting state brain networks

are all at play in driving what we are calling

desire, love, and attachment.

So in keeping with the exploration of the fact

that there’s a saying or a book or a song

or an example of pretty much any relationship dynamic,

I want to now talk about an article that came out

a little over 10 years ago

that talked about the universality of love

and the ability to fall in love.

So this would be very much in line

with the George Bernard Shaw quote that I mentioned earlier,

that love is really overestimating

the differences between individuals.

And again, I should say that is not something

that I personally believe,

although maybe I’m just deluding myself.

I like to think that the people that we fall in love with

are really special for us,

that they could not easily be replaced with anybody else.

That’s simply my stance.

I’m not basing that on any hardcore

neurobiological mechanism,

but nonetheless,

an article was published in the New York Times in 2015

that related to some psychological studies that were done

as well as some clinical work,

as well as some what I would call pop psychology

or things that fall outside

the domains of academic science.

And the whole basis of this article

was 36 questions that lead to love.

And it involved a listing out indeed of 36 questions

divided into set one, set two, and set three

that progress from somewhat ordinary questions

about life experience and self-report

to more, let’s call them deep questions

about people’s values

and things that are emotionally close to them.

And I’ll just give an example of a few of these.

You can find this easily online

by just putting into your search engine,

36 questions that lead to love.

Some of the questions in set number one were, for instance,

what would constitute a perfect day for you?

For what in your life do you feel most grateful?

Kind of standard questionnaire stuff.

In set two, what is your most treasured memory?

What is your most terrible memory?

So these are, as you can tell,

are drilling a little bit deeper

into one’s personal experience and emotional system.

And then set three, questions 25 through 36

are things, you know,

what is a very embarrassing moment in your life?

When did you last cry in front of another person

and by yourself?

What is something that’s too serious to be joked about?

So it’s going deeper into one’s emotional system.

And even questions like, of all the people in your family,

whose death would you find most disturbing and why?

So pretty, pretty heavy stuff there at the end.

Now, the reason this article got so much traction

and the reason I’m bringing it up today

is that there was a statement

that was made in and around this article

that if two people went on a date

or simply sat down and asked each other these questions

and each answered these questions

and the other was paying attention carefully

and at some level emotionally responding

or not responding, but certainly paying attention

to the answers of the other person,

that by the end of that exchange

where one person asks 36 questions

and the other person answers all 36

and then the other person asks all 36

and the other person answers all 36,

that they would fall in love, right?

Which seems like kind of a ridiculous thing.

And yet it is the case

that people who go through this exercise

report feeling as if they know the other person quite well

and feeling certain levels of attachment

or even love and desire for the other person

that they would not have predicted, excuse me,

would not have predicted

had they not gone through that process.

So what’s going on in this exchange of questions and answers

of a progressively more emotional and deep level?

Well, what I predict is going on

is that inside of that exchange,

people are creating a sort of delusional story

about the nature of the exchange

being a reflection of some deeper attachment.

And so even though people are just exchanging words,

they’re not physically touching.

They are not, at least not at the point

where they’re running these kinds of questionnaire studies.

They may touch afterwards for all I know

and probably did in some cases,

but they’re not exchanging life experience

in an immediate way.

They’re not actually going off into the world

and doing things together yet.

They are simply exchanging narrative.

But we know based on recent studies,

and I’ve covered this before on this podcast,

but I’ll mention again,

there was a study published in Cell Reports,

a Cell Press journal, excellent journal,

showing that when individuals listen to the same narrative,

their heart rates tend to synchronize

or at least follow a very similar pattern,

even if they’re not in the same room

listening to a given narrative.

Whereas in this case, people are facing one another,

listening to the narratives of each other.

Certainly they are having autonomic responses.

And it stands to reason

that their autonomic nervous systems are synchronizing

much in the same way that the Cell Reports study found

that people will synchronize their autonomic nervous systems

to a shared herd story from another.

In other words, whether or not we hear a story,

watch a movie, listen to a song,

or exchange our own individual stories,

our autonomic nervous systems have the potential

to map onto one another.

So I’m not all that surprised that people find

that they fall in love, in quotes,

after answering these questions to one another,

because essentially the way these questions are laid out

is they establish a narrative.

They establish a very personal narrative

and the other person is listening very closely.

And we don’t have physiological or brain imaging studies

to support what I’m about to say,

but the reasonable interpretation

is that that’s causing some sort

of autonomic synchronization.

So if you want to try this on a date or even,

it’s actually been hypothesized

that this could be useful for existing couples,

even if they already know the answers

to some of these questions.

And that doesn’t surprise me either.

I think the autonomic coordination

is present during mating behavior.

It’s present during shared experience of the outside world,

movies, concerts, watching one’s children

with somebody else, et cetera.

And it’s established by sharing one’s own narrative

of their own personal experience.

So I don’t want to seem overly reductionist.

I’ll never propose that all of our sensation, perception,

action, and experience in life boils down

to us just being bags of chemicals

and the action of those chemicals

or any aspect of our nervous system.

And yet, in looking across the psychological literature

of development of attachment,

in the psychological literature

of adult and romantic attachment,

and what makes and breaks those attachments,

it’s very clear to me,

and I think courses through the literature

at multiple levels,

that autonomic coordination is absolutely key

for the establishment of desire, love, and attachment.

In fact, I talked earlier about how our actual conception

is born out of autonomic coordination

of one sort or another.

So again, it doesn’t necessarily mean

that autonomic nervous systems always be synchronized.

In the case of the two categorizations

that Fisher proposed of the director slash testosterone type

and the nurturing follower slash estrogen type,

it was actually the coordination,

but in opposite directions of individuals

that fall into each of those categories

that led to more stable attachments

or the seeking out of those attachments, I should say.

But nonetheless, it’s, at least to my mind,

very clear that autonomic coordination

is a hallmark feature of desire,

a hallmark feature of what we call love,

and a hallmark feature of what we call attachment,

and that the breaking of attachments

or the failures of desire,

the failures of love,

and the failures of attachment over time

in line with the work of Gottman and others,

and even just simply what’s required for mating behavior

is also reflected in the autonomic nervous system.

But in that case,

a failure to coordinate the autonomic nervous systems

in some sort of concerted way.

Any discussion about desire, love, and attachment

would be incomplete if we didn’t talk

about the dreaded infidelity and cheating.

You know, much has been made of infidelity and cheating

and whether or not people who are higher on dopamine

and sensation seeking tend to cheat more or less.

Frankly, I don’t think there’s any solid evidence for that.

I think there are a lot of examples

that we can draw from in our own lives

and in the lives of others

that would generally support one or the other model,

but I’m not aware of any decent physiological studies

or psychological studies that really point to that.

For instance, I would never say

that the serotonergic phenotype as described by Fisher

is less prone to cheat,

or that the people who have an insecure attachment

are more likely to cheat, for instance.

I don’t think those correlations have been drawn

in any kind of meaningful way yet,

so I would be cautious about assigning them

without that evidence.

However, there are some interesting studies involving,

again, neuroimaging and some subjective measures in humans,

meaning asking them questions that they’re good ways

to tease out lies from truths in these sorts of studies,

and whether or not people tend to find their partner

or others more or less attractive

depending on how people feel about themselves.

And I think this is a very interesting aspect

to desire, love, and attachment for the following reason.

You hear a lot out there that, you know,

in order to form a really strong relationship,

you have to have a good relationship with yourself,

or you have to love yourself,

or you often hear, for instance,

that, you know, it’s exactly when you’re not looking

for a relationship that you’re going to find one.

You hear this stuff, right?

But none of that is really grounded in any studies.

Again, that’s like out of sight, out of mind,

or absence makes the heart grow fonder.

There are many life examples to support those statements,

and there are many life examples

to support statements to the opposite.

There’s a particular study that I found.

This was published in Frontiers in Psychology,

but it’s a experimental study that involves neuroimaging.

The title of this study is

Manipulation of Self-Expansion Alters Responses

to Attractive Alternative Partners.

And I love the design of this study.

What they did in this study is they took couples

and they evaluated members of that relationship

for what’s called self-expansion.

Now, self-expansion is a metric

that involves one’s perception of self

as seen through the relationship to the other.

And this is something that was developed

by the authors are Aaron and Erin.

So they have the same last name.

So I’m assuming this was either a sibling team

or a somehow related team or a romantic couple team,

A-R-O-N and A-R-O-N.

Aaron and Erin in 1986 proposed

this self-expansion model of close relationships.

And they proposed that people are motivated

to enter relationships, I’m reading here,

in order to enhance the self and increase self-efficacy.

In other words, that one of the reasons

why many people enter relationships

is that it makes us feel good about ourselves

and more capable.

And I would see that as a healthy interdependence,

not necessarily codependence.

This is especially strong at the beginning

of a relationship, it turns out,

when people are forming pair bonds.

And it’s the case that pleasure, arousal, and excitement,

again, all hallmark features

of autonomic nervous system function,

pleasure, arousal, and excitement,

give rise to self-expansion,

meaning to self-efficacy.

So what this self-expansion model is really about

is how great other people that we are close to

and romantically attached to can potentially make us feel,

in terms of what they say, in terms of what they do,

in terms of the way in which we believe they feel about us.

So it doesn’t necessarily have to involve

explicit statements of them telling us how great we are

or them doing great gestures for us,

but how we actually feel they feel about us

turns out to be a very strong parameter

in terms of how we feel about ourselves

and the relationship overall.

Now, some of you out there are probably thinking,

oh yeah, isn’t there this thing, the love languages, right?

I don’t have any neuroscience to support that.

I think the love languages,

I’m not super familiar with this, I didn’t list it out,

but that some people are,

their autonomic nervous system, if you will,

tends to be very responsive to gifts or to quality time

or to physical touch or acts of kindness.

I think I’ve got a few of these, right?

I probably have a few wrong.

Anyway, they’re easy to find online.

And people do tend to have a kind of a bias

toward two or three of these things

that are especially meaningful for them.

And when I hear meaningful, I hear,

they tend to push the autonomic nervous system

and neurochemical systems of the brain and body

in a direction that makes us feel good

as opposed to lousy or neutral.

In any event, this study looked at

whether or not people have high levels of self-expansion

through the actions or statements of their significant other

and how that influences their perception

of people outside the relationship,

meaning how attractive they perceive people

outside the relationship to be

turns out to be strongly influenced by,

A, whether or not their self-expansion

is very strongly driven by the other person

that they are involved with,

that they’re in the romantic relationship with,

and whether or not that’s being expressed to them.

So here’s how the study went.

First of all, they rated or categorized individuals

on the basis of the self-expansion metric.

Some people have more of a potential

to experience self-expansion through others, right?

Some of us feel great about ourselves

and we’re kind of topped off at that.

Others don’t feel so great about themselves,

but they can feel much better in response to praise,

in particular praise or self-expansion type behaviors

or statements from people that we really care about.

And still other people are a mixture of the two,

the kind of moderate levels of both.

So they rated them on this scale.

And then they had people experience

self-expansion narratives.

They heard their significant other

say really terrific things about them

and about the relationship in particular,

that the relationship that they have

was exciting, novel, and challenging.

So that was one form of self-expansion.

And they went into some detail as to why that was the case

in their particular relationship.

Or they heard a narrative from their significant other

about strong feelings of love between the two

that had been experienced previously in the relationship.

So in the one case, it’s sort of directed more towards them.

And in the other case,

it’s more about the relationship itself.

And then they did brain imaging

of one person in the relationship

while that person assessed the attractiveness

of people outside the relationship.

And what they found was that people

who were primed for this self-expansion

had lower activation of brain areas

associated with assessing others’ attractiveness

than did the people who experienced a lot of self-expansion.

Now, the takeaway from that,

at least the way I read this study,

is if you’re with somebody who really benefits from

or experiences a lot of self-expansion,

unless you really want them to pay attention

to the attractiveness of other people,

it stands to reason that they would benefit

from more self-expansion type gestures or statements.

Okay?

Not so much centered on the relationship.

We have such a great relationship.

There’s so much love.

It’s so great.

That too, but in the context of this study

and these findings that the person is really terrific,

that the relationship that they’ve created together

is really exciting, novel, and challenging,

that there’s a narrative around the relationship

that really has a lot to do with the dynamics

between the individuals,

in particular, that the person who really likes

self-expansion is vital to that dynamic.

Okay?

So it’s not looking down at the relationship

as a set of equals.

There is sort of this bias written into this

of that this person is really essential

for the relationship.

I’m not saying this is something that anyone has to do.

I’m not saying this is right or wrong.

This is just what the data say.

But what’s remarkable is that

in the absence of those statements,

people who have, or that rate high on this scale

of self-expansion rate attractive alternative partners

as more attractive.

Now that’s interesting to me because it means

that their actual perception of others is changing.

It’s not that their opportunity to see others is changing.

Right?

This is not a matter of them somehow getting access

or no access to attractive alternative partners.

Again, attractive alternative partners,

literally the language in the title of this paper,

they’re still seeing all these attractive people.

It’s just that if they’re feeling filled up in air quotes,

psychologically filled up, emotionally filled up,

autonomically filled, enhanced in the language

that we’re using today by the self-expansion narrative,

well then the same set of attractive faces

appear less attractive to a given individual.

Now, whether or not this predicts cheating or loyalty,

I certainly can’t say.

That would be very hard to assess in neuroimaging.

And there, of course, people rarely,

if ever report accurately their cheating behavior.

There’s some studies in which confidentiality is assured

to the point where people seem to be more trusting

and willing to reveal cheating behavior.

But if you look at the statistics on cheating behavior,

it’s very hard to track because people lie all the time

about their cheating in and outside of the context

of psychological and neuroimaging studies.

But I find this study, again,

the title manipulation of self-expansion

alters responses to attractive alternative partners

to be absolutely fascinating because again,

it points to the fact that the interactions

with our significant others shapes our autonomic arousal,

shapes our perception of self

and thereby shapes our perception

of other potential partners in the outside world

or shuts us down to the potential

of other people in the outside world.

So when I hear statements such as,

it’s important that you love yourself

in order to really fall in love with somebody else,

or it is when one is not looking for a relationship

that they’re most likely to fall in love

and form a stable relationship.

I can filter that through these findings to say that

it’s really the person who needs a lot of self-expansion

stimulating statements or actions coming from other people

that is most prone to seeing other potential partners

out in the world as attractive.

And in this sense,

we can return to the autonomic nervous system

as kind of a glass that it can be filled up

through various contexts.

It can be filled up through our own ability to regulate it.

It can be filled up through other people’s ability

to enhance our sense of wellbeing.

And in some sense,

this points to an idea where it is true

that the better that we can feel about ourselves

in the absence of any self-expansion type

input from somebody else

really does place us on more stable ground

such that when we do receive that praise,

or we do receive those acts of kindness or service

or physical touch or whatever they are,

that we are able to further enhance the way that we feel,

but that we don’t necessarily tether

all of our feelings of self-worth or self-expansion

to that one individual.

So you might think that if person A

can only receive the self-expansion from the statements,

from the action of the person they’re involved with,

person B, that that will form a very stable bond.

But what this study points to is the fact

that that’s a very unstable bond,

that person A is actually very susceptible

to the attractiveness of others

because they’re so desperately attached

to this notion of self-expansion,

even if they don’t realize it.

And so this really does point to the idea

that while it is important

to link our autonomic nervous systems

to establish desire, love, and attachment,

that we want to have a stable internal representation

of ourselves, a stable autonomic nervous system

to some degree or another,

so that we can be in stable romantic partnership

with another individual

if that’s what we’re really trying to do.

So until now, I’ve been weaving together studies

from the field of experimental psychology

and the fields of neuroscience,

in particular, neuroimaging.

But if you recall back to the very beginning of the episode,

when I was discussing how odors and how hormones

and how even birth control can shape people’s ratings

of attractiveness of others,

you’ll realize that there’s a deeper layer to all this,

which is that our biology

that resides below our conscious awareness,

things like our hormones, things like pheromones even,

are shaping the way that we choose, interpret,

and act with other potential romantic partners

or the romantic partners that we already have.

Now, this cannot be overemphasized, right?

No matter how much we would like to create

a sort of top-down description,

meaning from the cortex and our understanding of things

onto what we find attractive, who we find attractive,

what we enjoy, what we don’t enjoy

in the pursuit and romantic interactions with others,

there always seems to be, and indeed there always is,

a deeper layer in which our subconscious processing

drives us to find a particular person

to be particularly attractive,

or in which we have chemistry with somebody,

or in which we lack chemistry with somebody.

And I would say that one of the more exciting, fascinating,

and indeed mysterious aspects of desire, love,

and attachment are those subconscious processes,

those things that we call chemistry, right?

I mean, people will report, for instance,

that somebody’s smell is just absolutely,

positively intoxicating for them,

or that somebody’s smell is absolutely repulsive to them,

and they don’t know why.

That the taste of someone’s breath,

and I don’t mean that in any kind of poetic sense,

I literally mean the taste of somebody’s breath,

in some cases, can be very exciting to somebody.

And believe it or not, we can taste each other’s breath.

I talked about this in the chemical sensing episode

some months back, but we actually have receptors

for taste and smell that engage in coordinated action

such that we can’t really separate taste and smell

at some level, and this is especially true

when it comes to the formation of romantic relationships

and what we call chemistry.

Now, is chemistry absolutely required

for forming stable attachments for love and for desire?

No, of course they’re not.

But in general, these are primitive mechanisms

that exist in all animals.

They exist in special forms in humans,

but that they drive us toward behaviors that will,

as the theory goes, lead to love and attachment.

Not always, as Dr. Fisher pointed out,

that sex and sex drive is one way to explore

potential love relationships

and to explore potential attachments,

which of course are major investments

that extend well beyond one night or a week

or a vacation or even a year.

When we talk about stable attachments,

in general, that means long-term attachments in humans.

Now, there is a biology to all of that chemistry stuff,

and the studies of oral contraception

and men finding women more attractive

at certain phases of their menstrual cycle

and women finding men more attractive

at certain phases of the woman’s menstrual cycle

point to the incredible power

of those deeper biological mechanisms.

In the Huberman Lab podcast,

I discuss both science and science-based tools,

and so I’d be remiss if I didn’t actually cover

some of the tools that relate

to those deeper biological mechanisms.

Now, the hormones, testosterone and estrogen

are almost always the first biological chemicals

and hormones that are mentioned and described and explored

when thinking about desire

and love and attachment too, for that matter,

since love and attachment stem from desire.

I did an entire episode

about the biology of testosterone and estrogen

and ways to optimize testosterone and estrogen.

You can easily find that episode at hubermanlab.com.

It’s timestamped.

There, you can find all sorts of information

about how certain behaviors or absence of behaviors

drive up or down testosterone and estrogen.

I also dispel some myths about sexual behavior

and things like masturbation

and how they relate to testosterone and estrogen,

as well as some myths about

how those hormones change across the lifespan.

I also talk about the role of exercise.

I talk about supplementation,

and I also talk a little bit

about hormone replacement therapy,

although that will be the topic for a future episode.

So if you’re interested in the biology

of testosterone and estrogen,

two hormones that absolutely influence things

like libido and desire,

please check out that episode

as well as what I’m going to talk about

in just a moment here.

The simple stereotyped version of the hormones,

testosterone and estrogen,

are that testosterone drives libido

or increases it, aka sex drive,

and that estrogen somehow blunts it

or is not involved in libido and sex drive.

And that is simply not the case.

As I describe in that

testosterone and estrogen optimization episode,

and as I’ll tell you now,

yes, testosterone and some of its other forms

like the hydrotestosterone

are strongly related to libido and sex drive

and the pursuit and ability to mate.

However, the hormone estrogen

is also strongly associated

with libido and mating behavior.

So much so that for people that

either chemically or for some other reason

have very low estrogen,

libido can severely suffer.

So it’s a coordinated dance of estrogen and testosterone

in both males and females

that leads to libido or sex drive.

So I absolutely wanted to make clear

that it’s not a simple relationship

between testosterone and sex drive

or estrogen and sex drive.

Both are required at appropriate ratios.

Now, with that said,

there are things that can shift libido

in both men and women

in the direction of more desire

or more desire to mate,

either to seek mates or to mate with existing partners.

And there’s a quite solid literature

around a few of those substances.

Now, a common misconception

is that because dopamine is involved in motivation and drive

that simply increasing dopamine

through any number of different mechanisms or tools

will increase libido and sex drive.

And that’s simply not the case

either.

It is true that some level of dopamine

or increase in dopamine is required

for increases in libido.

However, because of dopamine’s relationship

to the autonomic nervous system

and because the autonomic nervous system

is so intimately involved, no pun intended,

in sexual activity, in seeking and actual mating behavior,

as I described earlier,

it’s actually the case

that if people drive their dopamine system too high,

they will be in states of arousal

that are high enough such that they seek

and want sexual activity,

but they can’t actually engage the parasympathetic arm

of the autonomic nervous system sufficient

to become physically aroused.

Now, there’s a whole description of this

that awaits us in a future episode,

but I’ll summarize now by saying

for people that are taking substances

just simply to increase dopamine

in order to increase libido,

that can be a potentially hazardous route to follow

because depending on whether or not

that dopamine level is high enough

that it puts them into a mode of seeking mates or mating,

but they can’t adjust their autonomic nervous system

during actual mating behavior.

What essentially is I’m saying

is it can place people into a chronic pursuit,

but an inability to perform sexually,

and this is true for men and women, okay?

So I would just caution people against just thinking,

oh, a lack of libido is simply a lack of dopamine.

That is not the case.

It could be from lower levels of dopamine,

but it could also be for other reasons.

And so these systems,

these signaling systems and these neurochemicals

are very intricate and just simply ramping up dopamine

has actually been found, for instance,

in amphetamine and cocaine users.

There is a phenomenon in which they become hyper aroused,

but can’t perform sexually.

This is also true for people who take elevated levels

of other recreational drugs or who take antidepressants

that increase the dopamine system too much, right?

Dosage has to be worked out with your physician,

with your psychiatrist,

such that mood is enhanced

and the various aspects of a healthy wellbeing,

mind and body are enhanced,

but not so much so that what we call the arousal arc

is locked with the seesaw in the sympathetic drive position

such that sexual arousal can’t occur, okay?

So this is an important point to make

because I think that a lot of people

are under the impression

that if they just drive up testosterone,

increase dopamine,

and generally get themselves

into high states of autonomic arousal,

that that’s going to increase their libido.

But that’s simply not the way the system works.

It’s that seesaw and that seesawing back and forth

that is the arc of arousal that we talked about earlier.

Now, there are substances, legal over-the-counter substances

that fall under the categorization of supplements

that do indeed increase libido and arousal.

And so I’m going to talk about some of those

in the context of peer-reviewed literature now.

I want to be clear, however,

that these are by no means required.

Many people have healthy libidos

or have libidos that are healthy for their life

and what they need and want.

And as always, in any discussion about supplementation,

you absolutely have to check with your physician.

I don’t just say that to protect us,

I say that to protect you.

Your health and wellbeing is dependent on you

doing certain things and not doing others,

and everybody is different.

Nonetheless, there are studies

that point to specific substances

that are sold over-the-counter

that at least in the United States are legal

and that have been shown

to be statistically significant

in increasing measures of libido.

There are many such substances,

but three that in particular

have good peer-reviewed research to support them

are MACA, M-A-C-A, which is actually a root,

Tongat Ali, also sometimes called Long Jack,

I didn’t name them, forgive me,

and Tribulus, or Tribulus it’s sometimes called.

I’m going to talk about each of these in sequence.

But on the whole,

the studies on MACA are quite convincing

that consumption of two to three grams per day of MACA,

which generally is sold as a powder or a capsule,

typically consumed early in the day

because it can be somewhat of a stimulant,

meaning it can increase alertness

and you wouldn’t want it to interfere with sleep

by taking it too late in the day.

But in studies that include both men and women

of durations anywhere from eight to 12 weeks

of athletes and non-athletes

and different variations of MACA,

it turns out there’s black MACA, red MACA, yellow MACA,

there are a bunch of different forms of MACA,

but that they can increase subjective reports

of sexual desire independent of hormone systems,

meaning it does not seem,

at least based on the existing literature,

that MACA increases testosterone or changes estrogen,

at least not on the timescales that these studies were done

or with the measures that were performed in these studies.

But that MACA, again, consumed in doses of anywhere

from two to three grams per day

has been shown to significantly increase libido.

And in fact, those dosages of MACA have been shown

to offset so-called SSRI induced sexual dysfunction.

So there are various routes to sexual dysfunction.

The SSRIs are selective serotonin reuptake inhibitors.

They go by name brands like Prozac and Zoloft

and there are many others now

and generic forms and so forth.

Those don’t always, I should point out,

lead to sexual dysfunction.

There’s a dose dependence.

Some people do quite well on SSRIs

and don’t have any issues with sexual function.

Other people suffer quite a lot from sexual dysfunction

while taking SSRIs, highly variable.

You need to work with a physician, a qualified psychiatrist.

But nonetheless, everything I’ve been saying about MACA

thus far has also been explored in the context

of SSRI induced sexual dysfunction.

The paper that I’m referring to here

is a double-blind randomized pilot dose finding study

of MACA root.

It goes by the name L-Mayeni.

These always have fancy names

and the Latin names in biology are always more complicated,

but it’s MACA root for the management

of SSRI induced sexual dysfunction.

First author is Dording, D-O-R-D-I-N-G.

This was a study done at Mass General,

which is one of the satellite locations

around Harvard Med, it’s associated with Harvard Med,

that found significant improvements in libido

when people were taking a pretty low dose.

It was actually, in this case, just 1.5 grams per day

up to a high dose, three grams per day of MACA.

And they were doing this in 20 remitted depressed

outpatients, so these are people that had depression.

Their depression was successfully treated with SSRIs,

but they were suffering from some of these SSRI

related sexual effects and MACA seemed to offset

some of those effects significantly in this population.

The other studies exploring the lack of effect

on serum testosterone in adult healthy men

was a 12-week study, again, consuming anywhere

from 1.5 to 3 milligrams, meaning 1, excuse me,

1,500 milligrams to 3,000 milligrams or placebo.

So again, this is 1.5 up to three grams

of MACA or placebo, and they rated sexual desire,

depression and other measures such as testosterone

in the blood, again, no change in testosterone

or estrogen, estradiol levels in men treated with MACA

and those treated with placebo.

But nonetheless, there was a significant

and positive effect on libido with this dosage

of 1.5 to three grams per day of MACA.

And there are several other studies that also show this,

again, in people that are taking SSRIs

and people that are not taking SSRIs.

In chronically over-trained athletes,

this was also found to be the case.

So it seems like across the board,

MACA is a fairly useful supplement

for those that are seeking to increase their libido.

And there are fewer studies involving women,

but there are a few such studies that also point

to the same general positive effect on libido

in women taking MACA at equivalent doses

to those I just described.

I think it’s noteworthy that MACA supplementation

does not seem to adjust testosterone or estrogen levels

to any significant degree, but it does change libido.

I think that points to the fact

that there are multiple systems in the brain and body

that influence libido, not just testosterone and estrogen.

And indeed, we know that to be the case.

Things like PEA, which is a substance found in chocolate

and is a substance that some people supplement,

is known, for instance, to increase sexual desire,

but also the perception of sexual experiences

as more stimulating, for instance.

So there are a lot of pathways in the brain,

in particular in the hypothalamus,

this ancient area of our brain that harbors neurons

and hormone-secreting cells, including neurons,

that can shape our perceptions

of even just our tactile experience

of others and their attractiveness,

and indeed can shift levels of desire

independent of changing levels of circulating hormones.

Another substance that has been shown to increase libido

across a range of human populations

is so-called tongkat ali.

I’ve talked a little bit about this

before on the Huberman Lab podcast

in reference to testosterone,

and I’ve talked about it extensively

as a guest on other podcasts.

Tongkat ali goes by a number of different names.

One of them is exceedingly difficult for me to pronounce.

It’s uricoma longifolia, also called longjack,

but tongkat ali is the typical name.

This is an herb.

There’s a Malaysian version and an Indonesian version.

My understanding is that the Indonesian variety

of tongkat ali is the one that is most potent

for its effects on libido.

Previously, I’ve talked about tongkat ali

taken in 400 milligram per day capsules

as a means to increase the amount of free,

meaning unbound testosterone.

So testosterone has a both bound form and an unbound form.

Very briefly, the bound form is bound to albumin

in the blood or to so-called sex hormone binding globulin.

When it’s bound,

it can’t be biologically active at many cells.

It is important that some of it be bound

in order to get a sort of time release

and proper distribution of testosterone through the body,

but is the unbound free testosterone

that can really have its most potent effects.

And there’s some evidence that tongkat ali

can increase the amount of unbound

so-called free testosterone

by lowering sex hormone binding globulin.

Although it is almost certain

that it has other routes of mechanism as well.

Nonetheless, there are some reports

of tongkat ali increasing libido.

One particular article, last author,

or I should say last name of first author, excuse me,

Ismail, I-S-M-A-L.

This was published in Evidence-Based Complementary

and Alternative Medicine.

It’s from 2012.

Reports a significant increase

in libido and sexual function.

There are other such studies, not a lot of them,

not as many robust,

controlled quality peer-reviewed studies

as there are from MACA.

Nonetheless, a number of people, men and women,

that I know do take tongkat ali

and it seems to work well for them.

The question always comes up

around discussion of supplements.

Do you need to cycle these things?

The only way to determine that

is really to do your blood work,

monitor liver enzymes, monitor hormone levels and so forth.

So I simply can’t say whether or not you need to

or you don’t need to cycle them.

Typically, tongkat ali and MACA are not cycled

in any regular kind of way that I’m aware of.

But again, you really need to check with your doctor

if you’re going to initiate taking any of these things.

And you certainly should do your best

to monitor your blood work

as well as subjective measures

and evaluating whether or not they’re working for you,

safe for you and so forth.

The third and final substance slash supplement

that I want to touch on as it relates to libido

is called tribulus terrestris.

So that’s T-R-I-B-U-L-U-S terrestris, T-E-R-R-E-S-T-R-I-S.

This is a commonly sold over-the-counter supplement

for increasing testosterone,

for fitness purposes and so on.

Whether or not it actually does that

to a meaningful degree isn’t clear,

but I’m aware of four peer-reviewed studies

that were focused on both males and females

ranging anywhere from 18 years old

all the way up to 65 plus, they say 65 plus,

I guess it could be 70, it could be 80, I don’t know,

but a fairly broad age range

where people took anywhere from 750 milligrams per day

divided into three equal doses.

So 750 total per day divided into three equal doses

of tribulus or placebo for 120 days.

This particular study was focused on females

and according to the female sexual function

index questionnaire, no significant difference

between any of the groups.

However, free and bioavailable testosterone

increased in the group taking tribulus terrestris,

total testosterone did not reach statistical significance.

So this is sort of the inverse of what we see with maca

where there do seem to be increases in testosterone,

which would predict that there would be increase in libido.

In this case, this was post-menopausal women,

there was no increase in libido,

there wasn’t increase in testosterone.

I mention it only because there might be instances

in which people want to increase their testosterone.

It does seem that tribulus, at least in that population,

is capable of doing that.

Now there’s a separate study that was done,

a double-blind study lasting anywhere from one to six months

that had a clear and significant increase in libido.

Now this was taking six grams,

so that’s 6,000 milligrams of tribulus root for 60 days.

And it did seem to increase various aspects

of sexual function.

And there was a, what appeared to be a substantial

16.3% increase in testosterone,

but in this particular study,

because of the variability across individuals

that did not actually arrive at statistical significance.

Now there were a number of other studies

that explored the role of tribulus in particular in females.

And one of those studies was a study

that was actually quite short.

It was two to four weeks, it involved 67 subjects.

These were subjects that had experienced a loss of libido

and took tribulus, divided into two equal doses,

compared that to placebo.

And they did see a significant improvement

in these measures of sexual desire and function

on this female sexual function index.

So there is some evidence that tribulus can be effective

in increasing testosterone in certain populations,

in increasing sexual desire and function,

in certain populations, in particular in females.

I think more studies are certainly needed,

but these three substances slash supplements,

maca, tonga ali in particular,

Indonesian tonga ali and tribulus

can indeed create significant increases in sexual desire.

And in some cases by adjusting the testosterone

and estrogen system, in some cases,

not by adjusting the testosterone and estrogen system,

again, pointing to the complexity of neurochemicals

and features that adjust things like libido, aka desire.

So we covered a lot of material today

related to desire, love, and attachment.

And yet I acknowledge that it is not exhaustive

of the vast landscape that is the psychology and biology

of desire, love, and attachment.

Nonetheless, I hope that you found the information

interesting and hopefully actionable in some cases

toward the relationships of your past, of present,

and potentially for the relationships of your future.

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♪ Yeah ♪