February 10, 2025 • 49 mins
What are we talking about neurobiologically when we talk about love? What does it have to do with how you were raised, the symmetry of someone's face, or the smell of their underarms? What do we learn from heartbreak, rom-coms, and little rodents called prairie voles? And what is the future of love & AI? Join Eagleman for a Valentine's Day special to learn what unseen sparks in the skull set the heart ablaze.
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Speaker 1 (00:05):
What is love?
Speaker 2 (00:06):
What does it have to do with how you were raised,
or the symmetry of someone's face or the smell of
their underarms. What are we talking about when we talk
about love and why does it change throughout our lives?
What do we learn from heartbreak? And what does this
have to do with sweaty T shirts or rom coms
(00:27):
or little rodents called prairie voles or the future of love.
Welcome to Inner Cosmos with me David Eagleman. I'm a
neuroscientist and an author at Stanford and in these episodes,
we sail deeply into our three pound universe to understand
why and how our lives look the way they do.
(00:49):
And today's episode, in honor of Valentine's Day, is about
love and neurobiology. What unseen sparks in the skull set
the heart ablaze whenever that person is nearby.
Speaker 1 (01:09):
Love.
Speaker 2 (01:09):
There aren't many words in our language that carry as
much weight or as much complexity as that one. As
we know from the pens of the lyric poets and
from our own experiences, love can make us feel invincible,
like we've discovered a secret force that governs the universe.
It can also make us feel weak and desperate and broken.
(01:32):
It can make us do things that seem in hindsight irrational.
Love is one of the main fuels behind the painting
of masterpieces, the writing of poetry, the composition of symphonies.
Love has inspired a large fraction of the stories in
our literature, whether we're talking about Romeo and Juliet or
(01:53):
Pride and Prejudice, or every rom com that follows the
same formula, and somehow we never get tired of it.
And love also drives real, concrete actions. It's the reason
a mother will throw herself in front of danger to
protect her child. It's the reason, at least in some cases,
why when thousand ships can be launched for war. Love
(02:17):
is a powerful force in the human story. But the
question that a biologist might ask is what is love?
Is it an emotion like anger or sadness? Is it
something deeper? Is it a biological drive like hunger or thirst?
Is it a trick played on us by evolution to
keep us reproducing. So that's what we're going to unpack today.
(02:41):
But here's the starting point. Love is biological. It's a
symphony of neural circuits firing in just the right patterns
and a well timed dance of neurotransmitters and hormones. So
the first question we're going to ask is, as we
come to tie the experience of love to biology and
(03:01):
words like limbic system and dopamine and oxytocin, does that
make love less meaningful or does it make it more profound? So,
before we get into the meat of today's episode, I
want to tackle that question head on by reading a
very short story called Blueprints from my book Some we
look forward to finding out answers in the afterlife, where
(03:25):
in luck. In the afterlife, we are granted the ultimate
gift of revelation, an opportunity to view the underlying code.
At first, we may be shocked to watch ourselves represented
as a giant collection of numbers as we go about
our normal business in the afterlife. In our mind's eye,
(03:47):
we can see the massive landscape of numbers stretching to
site's limit. In all directions. This set of numbers represents
every aspect of our lives. Across its vast plane, we
spot islands of sevens, jungles of threes, branching rivers of zeros.
The size and richness are breathtaking as you interact with
(04:11):
a lover, you can see her numbers as well, and
her interactions with yours. She endearingly sticks out her bottom
lip for attention, and your numbers cascade into acrobatics. Digits
flip their values like waterfalls. As a result, your eyes
lock onto hers, and amorous words form on your lips
(04:34):
and travel from your throat.
Speaker 1 (04:36):
In air compression waves.
Speaker 2 (04:38):
As she processes the words, her numbers flip waves of
change rippling through her system. She returns your affection as
dictated by the state of her numbers. My goodness, you
realize on your first afternoon here, this is totally deterministic.
Is love simply an operation of the math? After watching
(04:59):
enough code, a new notion of agency and responsibility dawns.
Speaker 1 (05:05):
You watch and understand.
Speaker 2 (05:07):
All the signals that lead to a driver stomping on
her brakes as her numbers are changed by the numbers
of the cat walking in front of the wheels. You
can even see the code of the fleas that leap
off when the cat leaps. Whether the cat is struck
or not struck, you now understand, was not in anyone's control.
Speaker 1 (05:26):
It was all in the numbers.
Speaker 2 (05:28):
Married together in a gorgeous inevitability. But we also come
to understand that the network of numbers is so dense
that it transcends simple notions of cause and effect. We
become open to the wisdom of the flow of the patterns.
If you assume this gift of revelation is received in heaven.
Speaker 1 (05:47):
You're only half right.
Speaker 2 (05:49):
It is also the punishment designed for you in hell.
The rewards originally thought to offer it as a gift,
but the punishers quickly decided they could leverage it as
a kind of affliction, drying up life's pleasures by revealing
their bloodlessly mechanical nature. Now the rewarders and the punishers
(06:11):
are in a battle to determine which of them gets
more benefit out of this tool.
Speaker 1 (06:16):
Will humans appreciate.
Speaker 2 (06:18):
The knowledge or be tortured by it? The next time
you're pursuing a new lover in the afterlife, perhaps sharing
a bottle of wine after what appeared to be a
chance encounter, don't be surprised if both a rewarder and
a punisher sneak up behind you, the reward whispers into
one of your ears. Isn't it wonderful to understand the
(06:40):
code the punisher hisses into your other ear, does understanding
the mechanics of attraction suck all the life out of it?
Such a scene is typical in the afterlife and illustrates
how much both parties have overestimated us. This game always
ends in disappointment for both sides, who are freshly distraught
(07:02):
to learn that being let into the secrets behind the
scenes has little effect on our experience. The secret codes
of life, whether presented as a gift or a burden,
go totally unappreciated, and once again the rewarder and the
punisher skulk off, struggling to understand why knowing the code
(07:24):
behind the wine does not diminish its pleasure on your tongue.
Why knowing the inescapability of heartache does not reduce its sting.
Why glimpsing the mechanics of love does not alter its
intoxicating appeal. That was the story Blueprints from my book
(07:46):
sum and that was my way of arguing that it's
possible for us to deeply study the biological codes that
underlie love, and no amount of knowledge about the biology
the codes will ever touch direct experience of love. In fact,
as science has taught us for centuries, deeper insight generally
(08:07):
only enhances the splendor. You may know the story about
the physicist Richard Feinman. He was talking with an artist
friend of his who held up a flower and said,
look how beautiful this flower is, and Feineman agreed. And
then his friend said, I, as an artist, can see
how beautiful this is, but you, as a scientist, take
(08:29):
this all apart, and it becomes a dull thing. First
of all, Feineman pointed out quote, the beauty that he
sees is available to other people and to me too.
Although I may not be as refined aesthetically as he is,
I can appreciate the beauty of a flower. At the
same time, I see much more about the flower than
he sees. I can imagine the cells in there, the
(08:52):
complicated actions inside, which also have a beauty. I mean,
it's not just beauty at this dimension at one centimeters,
there's also beauty and smaller dimensions, the inner structure, also
the processes.
Speaker 1 (09:04):
The fact that the.
Speaker 2 (09:05):
Colors in the flower evolved in order to attract insects
to pollinate it is interesting. It means that insects can
see the color. It adds a question. Does this esthetic
sense also exist in the lower forms. Why is it esthetic?
All kinds of interesting questions which the science knowledge only
adds to the excitement, the mystery, and the awe of
(09:28):
a flower. It only adds end quote. So with this
in mind, that knowledge only adds to the awe and
beauty we can appreciate, we're going to dive into the
science of love. What happens in the brain when we
fall in love? Why does attraction feel so intense? What
does heartbreak have in common with physical pain? And what
(09:49):
makes long term love last? So let's begin inside the brain.
When we look at the circuitry and chemicals in the brain,
we find that love correlates with particular patterns, they carefully
balanced mixture of different areas and molecules. So how can
this be studied? Well, I'll give you an example. In
two thousand and five, Helen Fisher and her colleagues published
(10:11):
a new kind of study. They were thinking about how
scientists have long described the things that animals do to
attract mates, but there was almost nothing known about the
brain mechanisms by which the mate becomes attracted. So they
set up a study with brain imaging fMRI, and they
scanned a bunch of college kids who were in the
(10:32):
throes of romantic love. The participants viewed pictures of that
special someone, and they also looked at pictures of acquaintances,
and the photos of the people they were romantically involved
with caused the participant's brain to become active in regions
that traffic in dopamine, like the caudate nucleus, which is
(10:53):
associated with reward detection and expectation, and the ventral tegmental area,
which spits out dopamine all over the brain and is
associated with pleasure and focused attention and the motivation to
pursue and acquire rewards, and is by the way, a
very evolutionarily old circuit. So this is what's thought to
(11:13):
make love euphoric, like cocaine or alcohol. You've certainly heard
of dopamine as a molecule that drives addiction and craving,
whether we're talking about sugar or gambling or social media.
I don't want to oversimplify the story of dopamine, but
presumably this is why new love feels so exhilarating, and
(11:34):
why time spent with that person feels so rewarding, and
why being away from them feels like withdrawal. Now These
dopamine systems link with other brain areas, for example, the
nucleus ccumbins, the amignala, the hippocampus pre federal cortex, and
these areas all collaborate to keep chasing pleasurable behavior. And
(11:55):
this is the same circuitry we see getting juiced up
in sex and food and drugs. So when we're falling
in love, chemicals associated with the reward circuits flood our
brains and this gives us a number of things that
we recognize in love. The faster heart, the sweatier palms,
the flush cheeks, the feelings of passion and anxiety. When
(12:17):
people talk about love being like a drug, this is
what they have in common. But dopamine is only part
of this equation. During this initial phase of romantic love,
you also get more of the stress hormone cortisol, which
essentially tells your body there's a crisis you have to
deal with. And this is presumably why the person of
(12:39):
your attraction can take up so much mental real estate.
This is the object to be attended. And there's more.
During that first swell of passion, there's a neuromodulator slash
hormone called oxytocin that starts playing a big role. This
gets released when we hug, while we cuddle, when we
(13:00):
make eye contact. Oxytocin is released during sex and it's
heightened by skinned skin contact, and it deepens these feelings
of attachment and it makes couples feel closer to one
another after having sex. And there are lots of other players,
like testosterone in men and women that seems to be
heightened during this initial attraction. It's possibly associated with what
(13:24):
makes desire feel urgent and what intensifies the physical attraction
in early relationships. High testosterone levels correlate with this intense
attraction and with risk taking behavior. Now we put all
this together, and it gives us a little bit of
insight into the old expression that love is blind. And
that's because romance seems to also tamp down the neural
(13:47):
pathways involved in fear and social judgment. In other words,
when your heart's on fire, smoke gets into the neural
machinery that's normally making critical assessments of the other.
Speaker 1 (14:01):
That's why early.
Speaker 2 (14:01):
Stage love makes us overlooked flaws, why it makes us
idealize our partners, why we sometimes ignore red flags. Okay,
(14:26):
so there are ways to study romantic love in the
brain in terms of the circuitry and chemicals, but you
can study the behavioral aspects as well. Who do we
find ourselves attracted to and why? And what I've always
found so wild is the way that our sense of
attraction runs entirely under the hood. There's essentially no conscious
awareness of any of it. You just find yourself attracted
(14:49):
to some people more than others. The first blushes of
love feel like magic, But underneath the poetry, underneath the
longing glances and racing heartbeat, attraction is a neural algorithm. Now,
we generally like to believe that we consciously choose our partners,
but a closer study tells us that our brains are
(15:10):
making calculations we're not even aware of pulling the strings
behind the scenes. So let's start with something visual. Facial symmetry.
A number of studies show that people across different cultures
are more attracted to symmetrical faces.
Speaker 1 (15:25):
Why.
Speaker 2 (15:25):
One hypothesis is that symmetry is a marker of good
genetic health. Through evolution, humans developed an unconscious preference for
partners who show fewer signs of developmental instability. A more
symmetrical face presumably means fewer genetic mutations, better resistance disease,
(15:46):
and higher likelihood to produce healthy offspring. And it's not
just symmetry. Certain features about other people are universally attractive,
even across different cultures. Men are drawn to features that
signal fertility. Curvy bar body, high cheek, bones, full lips,
all things that young girls and older women don't have.
(16:06):
Women tend to be attracted to different features, but the
same idea. It's signals of fertility. In the male, things
like strong jawlines or prominent browridges. More rugged features are
associated with higher testosterone, and its signs that young boys
and old men don't generally have. It indicates fertility. But
attraction isn't only about appearance. It's also about familiarity. People
(16:30):
often end up dating someone who looks just a bit
like them. There's a reason for that. We are wired
to find comfort in the familiar. In some cases, this
means we unconsciously seek out people who resemble our parents
because their faces are imprinted in our early neural development
as safe and trustworthy. This is called positive assortative mating,
(16:54):
which just captures the idea that we are often attracted
people who share our own physical or genetic traits. If
you examine married couples, you'll find that they're more likely
than chance to have similar eye colors, hair textures, levels
of attractiveness. There are many reasons for this, things like
implicit egotism, and there's individual differences in how much people
(17:16):
want a mate to look like them, But on average
this is true. So while we think we're making independent
choices in love, our brains are actually navigating us in
patterns even when we don't recognize them. But attraction is
about far more than what we see. It also involves
what we smell. As I talked about in episode eighty nine, humans,
(17:37):
like all our animal cousins, communicate through pheromones, which are
chemical signals that influence social and sexual behaviors. So while
we have no conscious awareness of them, they play a
role in determining who we find attractive. So one experiment
on this was the Sweaty T Shirt Study, which was
(17:57):
conducted by Klaus Wedekind and his colleague. Women were asked
to smell t shirts worn by different men and rate
which ones smelled the most attractive. The result was that
the women preferred the scent of men whose immune system
genes what are called their MHC genes, were somewhat different
from their own. In other words, the ladies were attracted
(18:19):
to the guys who were not genetically similar to them.
Why does this matter well, Evolutionarily, choosing a partner with
a different immune system means a greater variety of immune
defenses for potential offspring. It's nature's way of preventing inbreeding
and ensuring genetic diversity. Now, interestingly, birth control pills disrupt
(18:43):
this natural process. There were experiments by Craig Roberts and
colleagues that found that women who are on the pill
are more likely to choose partners whose immune profiles are
similar to their own, and that can be problematic because
when they go off the pill, their attraction to their
partner can sometimes change. So all this raises a question
(19:04):
to what extent is the attraction we feel out of
our hands. If something as small as a birth control
pill can alter our romantic preferences, what else is shaping
our choices without us realizing it. While psychologists have long
noticed that attraction isn't just shaped by these immediate biological factors,
(19:25):
it's also shaped by our past. So Researchers talk about
three primary attachment styles that are formed in early childhood
and this influences how we approach relationships. So first there's
people with secure attachment, where they feel comfortable with intimacy.
They tend to have stable, healthy relationships. But there's also
(19:47):
anxious attachment and people here crave closeness but have a
major fear of abandonment. They typically need a lot more
reassurance in relationships. And then there's avoidant attachment, and here
people value independence to the point of pushing others away.
They struggle with commitment. So when you see these different types,
(20:10):
you start to see patterns when they combine in couples.
For example, one of the most common and toxic relationship
patterns is called the anxious avoidant trap. This happens when
someone with an anxious attachment who craves closeness falls for
someone with an avoidant attachment who fears closeness, and the
(20:31):
result is this constant push and pull dynamic, or one
person chases while the other withdraws. Now, researchers have studied
this kind of thing in brain scanning, and what they
find is that people with secure attachment have more regulated
activity in their pre federal cortex, which presumably allows them
to process emotions in a balanced way. But people with
(20:53):
anxious attachment show a lot more activity in regions associated
with fear and threat detection, so their brains are strongly
wired up to detect potential rejection. And it's the same
with people with avoidant attachment styles. They also have cranked
up threat detection, but in this case it has to
do with being exposed to cues that trigger feelings of closeness,
(21:17):
and they also tend to have less activity in reward
centers for positive social stimuli. So sometimes the paths we
take aren't about choices in the moment, but patterns set
down in our brains long before we even enter the
dating world. And attraction isn't just about biological signals and
(21:38):
personality compatibility.
Speaker 1 (21:39):
It's also about novelty.
Speaker 2 (21:42):
Remember that the reward systems in the brain are heavily
geared for novelty, for new experiences. This is why early
stage romance feel so intense. It's new and unpredictable and exciting.
The brain gets a lot of dopamine hits when we're
around someone that we're falling, and it reinforces the sense
(22:02):
of obsession and pleasure, and just consider this in your
own life. Sometimes, when you start seeing someone new, everything
about them is fascinating, the way they laugh, the stories
they tell, even the way they twitch their nose when
they laugh. Every moment with them feels electric. But over time,
this novelty fades. Your brain adapts. What was once thrilling
(22:26):
becomes familiar, and this is where attraction starts to shift.
Some people chase that initial high, moving from one relationship
to the next in search of that early stage rush.
Others transition into long term love. But this raises a
question can love last forever? We often think about love
(22:47):
is something that fades over time. The passion cools, the
excitement diminishes, and eventually that person who once made your
heart race becomes just another part of your daily routine.
But is that inevitable? Does love have a neural expiration date?
Some people argue that monogamy is not natural. After all,
(23:08):
as we just said, your reward systems thrive on novelty,
and there are arguments that humans evolved for serial pair bonding,
meaning we're wired to stay with a partner for a
certain number of years, often just long enough to raise
young children before moving on, and there's some evidence for this.
In many cultures, divorce rates spike around the four year mark,
(23:31):
so that leads some researchers to suggest that romantic love
does have a built in expiration date. The brain is
wired for change, and that long term monogamy requires conscious
effort rather than biological instinct. And indeed, it's inevitable that
there's a change in neural activity over time because the
high energy drug addiction of early romance can't keep going forever.
(23:55):
But that doesn't mean the spark of passion has to
get extinguished. There was a study in twenty eleven and
they performed brain imaging on couples that had been married
an average of over two decades. So they showed them
their partner's face, and they also showed control images of
other faces, like a friend or someone they didn't know well.
(24:17):
And what they found in response to the loved one
was the same kind of reward related activity as new
lovers had, for example in the ventral tegmental area and
dorsal stratum. In other words, the reward systems involved in
romantic love can stay sparking along for decades. And what
(24:38):
they found in the study was that Several other areas
were active, depending on the kind of relationship the people
had developed. Some people had a more friendship based love,
and these folks they saw more activity in the same
kinds of regions we see in maternal.
Speaker 1 (24:53):
Attachment, like the globis palladus.
Speaker 2 (24:56):
Other brain areas correlated with the couple's frequency of having sex,
like the hypothalamus and posterior hippocampus. The activity of other
areas correlated with obsession, like the caud eight. Other areas
correlated with the degree of romantic love and the inclusion
of the other in the self areas like the ventral
(25:17):
tegmental area. Anyway, don't worry about the details, but the
encouraging thing this demonstrates is that the excitement, the reward
of romance can stick around. Maybe it mellows a bit,
but the key is that it's accompanied by more rational
cognition rather than the emotional roller coaster. In other words,
reward centers are still cranking along as loving relationships proceed,
(25:40):
but the relentless itch of desire subsides. Your cortisol and
other stress hormones gradually return to equilibrium. You get the
closeness without the overwhelm As a result of these brain changes,
the connection with your partner deepens into something less obsessive
in consuming, into something where your partner becomes deeply ingrained
(26:04):
into your internal model. They work their way into your
neural circuitry. They literally become a part of you. In
this way, there's a drift from passionate love into what's
called compassionate love. Euphoria is slowly replaced with depth. And
let's return to the neuromodulators. Oxytocin isn't just involved in
(26:27):
the early throes of romantic love. It also helps transform
attraction into attachment. I mentioned oxytocin earlier as a cuddle hormone,
but it's also known as a bonding hormone. It gives
feelings of contentment and calmness and security, all of which
are elements of mate bonding. By the way, you also
(26:49):
find oxytocin underlying the bonds between parents and children, or
between close friends, or between humans and their pets. And
it's not just oxytocin. There's another other hormone called vasopressin
that plays a key role in commitment and loyalty. I'll
take a second here to tell you about prairie voles,
which are these very cute mouselike rodents. And the thing
(27:12):
about prairie voles is that one of the few monogamous
species in the animal kingdom. They pick a partner and
they stick together. Now, not surprisingly, there's some individual differences
among these voles, and it turns out that voles with
higher vasopressin levels are more likely to stay with their
partners for life. But if you block vasopressin receptors in
(27:35):
these voles, they lose interest and start behaving like polygamists.
And it's generally thought that vasopressin works this same way
in humans. So long term love is not just about emotion,
it's about chemistry. In the dark of the skull, the obsessive,
dopamine driven intensity of early love can transform into something deeper.
(28:01):
In other words, while early stage romance is driven by
novelty and excitement, long term love is governed by a
slightly different set of neural circuits, ones that promote attachment
and stability. So while passion might naturally fade, deep emotional
attachment can last a lifetime if the right conditions are met.
(28:22):
So while a lot of relationships fail, long term love
is possible and here's what we want to consider on
Valentine's Day. What do successful long term couples do differently.
The research shows that it boils down to five things. First,
successful couples keep novelty alive. As we saw, dopamine correlates
(28:43):
with novelty, which is why new relationships feel so exciting.
But over time, the brain adapts, so the challenge is
to introduce new experiences into the relationship. Traveling, learning new skills,
trying a new restaurant. These sorts of things can juice
up the brain's reward pathways, So while the brain naturally
(29:03):
adapts to familiarity, novelty can bring back some of that magic. Second,
couples maintain physical touch, which triggers oxytocin. Couples who continue
to hug and kiss and cuddle maintain stronger bonds. Third,
they figure out how to reframe conflict. There's no relationship
(29:24):
that's free from conflict, but how couples handle it determines
whether their love survives. Research from John and Julie Gatman
suggests that the key to long term success is the
ratio of positive to negative interactions. So couples who maintain
at least a five to one ratio of positive interactions
(29:46):
to negative ones are more likely to stay together. In
other words, it's not about avoiding conflict, which is impossible.
It's about balancing negativity with emotional repair. Fourth, it's important
to cultivate gratitude. One of the simplest ways to sustain
love is by expressing appreciation. Couples who actively express gratitude
(30:09):
towards each other have increased activity in the brain's reward system. Finally,
good couples grow together, and this may be the biggest
factor in long term love is shared growth. Couples who
support each other's personal development are more likely to stay together,
whether that's pursuing career goals, or learning new things, or
(30:30):
evolving emotionally. Again, the brain thrives on change, and relationships
that allow for mutual growth tend to be the ones
that last.
Speaker 1 (30:40):
So what does all this tell us?
Speaker 2 (30:42):
That long term love is not just about finding a
compatible person. It's also about habits and effort and commitment.
Love isn't just something that happens to us, It's something
we build. So let's zoom out and take stock. Attraction
(31:12):
isn't random, and it's not fully captured by the pens
of the romantic poets. It's biological, it's chemical, it's psychological.
Our brains push us towards partners based on factors we
typically can't consciously recognize, factors from symmetry to pheromones, to
immune system differences to childhood attachment patterns. And it's a
(31:33):
very real feeling. And part of the way we can
appreciate the reality of it is by looking at how
and why it is so deeply painful to the brain
to lose love. Okay, so we've seen so far that
falling in love can be exhilarating, coming with a neurochemistry
cocktail that makes us feel euphoric and obsessed and connected.
(31:56):
But what happens when that love is taken away? What
happens when the person who once felt like the center
of our universe suddenly disappears. So in twenty eleven, a
team at the University of Michigan did a study that
helps explain the neuroscience of heartbreak. They placed heartbroken participants
(32:16):
people who had gone through a breakup inside an fMRI
scanner and showed them pictures of their exes, and when
people looked at photos of their lost love, the same
brain regions that process physical pain lit up, for example,
the anterior singulate cortex and the insulin. So heartbreak isn't
(32:38):
just something you imagine you're going through. It is physical.
Your brain register's romantic rejection like an injury. That's why
heartbreak isn't something you can just shake off and ignore it.
It's a real biological issue going on now. I argued
in my book Live Wire that this is because we
form an internal model of the person that we're with,
(33:00):
and your brain expects that person to be there, and
when that person is no longer there. It is like
drug withdrawal. If you use a drug, your brain expresses
more receptors for that chemical, and then it finds itself
in a bad situation when the drug is no longer present,
when its expectations go unmet. If you're interested in more
(33:23):
about this equivalence, check out episode twenty four of Inner Cosmos,
which is called what does drug withdrawal have in common
with heartbreak? Anyway? This is why heartbreak feels so consuming.
This is why people who go through a breakup often
find themselves obsessing over their ex or replaying conversations in
(33:45):
their mind, or scrolling through old texts, or feeling physically
unable to focus on anything else. They've been thrown into
a state of deprivation. Their brain is craving the relationship
that they've lost, just like craving a drug that's been
taken away. In heartbreak, as in drug addiction, people have
similar responses insomnia, loss of appetite, obsessive thoughts, mood swings,
(34:11):
sometimes physical pain like tightness in the chest. Essentially, your
nervous system is in panic mode. It's screaming, where is
that thing I expected? Bring it back. This is why
people can struggle to let go of an ax even
when they know the relationship was bad. Their rational brain
may understand that the relationship is over, but their brain's
(34:33):
emotional core, like the limbic system, hasn't yet caught up.
This is particularly true for people who were deeply in love.
Helen Fisher's research showed that the deeper the romantic attachment,
the stronger the withdrawal symptoms. Some people even experience broken
heart syndrome, which is a real medical condition. It's technically
(34:54):
called taco subo cardiomyopathy, where intense emotional distress temporarily weakens
the heart muscle, which mimics the symptoms of a heart attack.
So heartbreak can almost literally break your heart. Now, the
good news is that, because of plasticity, the brain has resilience.
(35:15):
Over time, the prefrontal cortex, which is involved in logic
and self regulation, begins to gain control again. It begins
to reframe the loss, helping you make sense of what happened.
If you've recently suffered a breakup this Valentine's Day, I'll
just remind you that the things that help our exercise
and social connection and novel experiences to replace old associations
(35:40):
over time, as you get over an x, new pathways form.
This means that one day thoughts of your ex won't
trigger pain anymore. Instead, they'll feel more distant, like an
old memory. As painful as heartbreak is, the thing we
might keep in mind about it is that it is
proof that love existed in the first place. The fact
(36:04):
that the brain is capable of experiencing this kind of
pain is a testament to how profoundly it is wired
for a connection. Okay, so what we've been talking about
in this episode is love, and now that you're imagining
sitting on a beautiful mountaintop, gazing at the long road
ahead with your loved one.
Speaker 1 (36:22):
Let's look at what.
Speaker 2 (36:23):
The future has in store for us. Will love always
look like it does now? Or are we going to
develop ways to engineer and tame it. Could we manipulate
the brain's chemistry to create or erase love at will?
So now we're going to look at what happens when
neuroscience collides with our technology. Love is generally something we've
(36:47):
accepted as organic, unpredictable, deeply human. We see people fall
for the wrong person, people stay in toxic relationships, people
find themselves hopelessly drawn to someone who doesn't love them back.
Love is messy, but what if it didn't have to be?
As we continue to unravel the neuroscience of love, we're
(37:07):
faced with a fascinating and unsettling possibility. Could we manipulate love,
could we create it, could we enhance it? Or could
we even erase it entirely? If love is just neurochemistry
in circuits, then in theory, we should be able to
hack it, And the truth is we are already doing that.
(37:30):
Scientists have long been studying drugs that enhance attachment and
romantic bonding. The most promising one is oxytocin, which I
mentioned earlier as.
Speaker 1 (37:40):
A bonding hormone.
Speaker 2 (37:41):
This is already available in nasal spray form, and when
you inhale it, it increases trust and emotional connection and
pro social behavior. And some studies suggest that oxytocin sprays
could be used as a tool to strengthen relationships, especially
in couples who are struggling with intimacy or emotional distance. So,
(38:04):
in one study, men in relationships had oxytocins squirted up
their noses, and they became closer to their partner and
less interested in attractive strangers. They kept a greater physical
distance from the strangers. In other words, a simple squirt
of oxytocin up the nose strengthened their commitment to their
(38:25):
partner and made them less interested in others. Now, imagine
a world where oxytocin therapy is a routine part of
couples counseling. Could we use brain chemistry to keep love
alive in struggling marriages, Could we artificially restore the feelings
of early romance in long term relationships? And if we can,
(38:48):
should we? Because while the idea of a love drug
might sound promising, it also raises ethical questions. If love
can be chemically induced. Is it's real If we use
a drug to feel connected to our partner, are we
experiencing genuine emotion or just a biological illusion? And then
(39:12):
there's the opposite question, what if we didn't want to
love as much? Is there a science to suppressing love?
Anyone who has suffered from heartbreak knows the unbearable ache
of longing for someone who has gone the sleepless nights,
the obsessive thoughts, the emotional pain that lingers for weeks.
Wouldn't it just be easier if you could turn it off? Well,
(39:35):
some scientists have been exploring the possibility of erasing romantic attachment,
of altering brain chemistry to dull or even eliminate the
pain of lost love, and it turns out this might
be possible. In twenty ten, researchers we're looking at beta blockers,
which is the type of drug used for high blood
(39:57):
pressure and chest pain and irregular heartbeat, and they discover
that beta blockers can also interfere with emotional memory formation.
In other words, if you give beta blockers to someone
right after a traumatic event, that weakens the emotional intensity
of that memory. So some people argue this could be
(40:19):
used to soften the pain of a heartbreak. Imagine taking
a pill after a breakup and it reduces your brain's
ability to attach strong emotions to memories of your ex.
The memories would still be there, but the pain associated
with them would be less and would fade faster. Okay,
(40:39):
so this is one approach to using pharmaceuticals to change
our experience with love. But what if we took this
even further? In animal studies, it turns out that blocking
certain proteins in the brain can erase emotional memories entirely,
and that's led to a speculation. Could we develop a
drug that erases love. Imagine a future where you walk
(41:01):
into a clinic and you have all memories of an
ex emotionally neutralized. Would you do it? And if we
had the ability to erase love, what would that do
to us? Would we fall in love more recklessly knowing
that we could erase the pain later, would relationships become
more disposable? Or would we lose something profoundly human the
(41:26):
ability to grow from heartbreak, to learn from our emotional wounds.
It's worth noting that heartbreak, as painful as it is,
is a part of our story that makes us who
we are. It shapes our future preferences and our boundaries
and our understanding of what we need in a partner.
If we erased love, would we lose all the wisdom?
(41:50):
And there's one more issue about the future of love,
and that has to do with the impact of artificial
intelligence on relationships. Would you actually fall in love with
a machine one that listens to everything you say and
has a perfect memory and never gets angry, and never
stops paying attention and always has a lovely and engaged
(42:13):
response to everything that you say. We currently understand love
as a human to human experience, but in the age
of artificial intelligence, I think it's possible this might change.
AI and virtual companions these are on the rise, so
consider apps like Replica, which give you a virtual companion
(42:33):
that you can talk with anytime, in the middle of
the night or whenever you're feeling lonely. Hundreds of thousands
of people are making emotional bonds with digital entities, and
it's no surprise that some fraction of these users have
reported falling in love with their AI companions. From a
neuroscience perspective, this of course makes sense. Love is at
(42:58):
its core about connection and emotional responsiveness, and if an
AI can mimic human behavior well enough, if it can
listen and respond with empathy and engage in meaningful conversation,
our brains might not make a meaningful distinction. I'm reminded
of the scene from the first episode of Westworld where
(43:21):
the young William is talking to the woman who's outfitting
him for his adventure, and she's giving him a hat
and a gun and so on, and he's not quite
sure if she's a human or a robot, so he
hesitantly asks. He says, I hope you don't mind if
I ask you this question, But are you real? And
she says to him, if you can't tell, does it matter?
(43:43):
And I think this is going to increasingly be a
key question for us with AI relationships. In Japan, apparently
there are already virtual spouses AI partners that lonely individuals
interact with daily. People hold ceremonies to marry their AI companions,
and some claim to feel a deeper emotional fulfillment from
(44:05):
AI than they ever did with human partners. Could AI
partners be the answer for people who struggle with social
connection or anxiety or past trauma, or would a world
filled with AI companions erode human intimacy, making real relationships
feel too difficult in comparison. If you're interested in this,
(44:27):
please listen to my episode thirty nine to hear a
much fuller argument on the pros and cons. But for now,
I'll just pose some questions about love and the future
of our technology, because with the advancements that we're in
the middle of right now, we're definitely going to be
confronting these. If we could enhance love, should we? If
(44:49):
we could erase love, should we? If AI can simulate love,
is it real? I think there aren't necessarily easy answers here.
On the one hand, technology could help people struggling with
loneliness or heartbreak or commitment issues. Imagine a world where
struggling couples could rekindle their passion with neurochemical therapy, Where
(45:13):
people suffering from unbearable grief over lost love could ease
their pain with a pill. Where those who fear rejection
or who have social anxiety could experience deep, fulfilling companionship
through artificial intelligence. On the other hand, there's something unsettling
about the idea of manipulating love. Would we lose something
(45:36):
essential and what do we conclude when love is no
longer something that happens to us, but something we can
turn on and off at will, would we still cherish it?
So to wrap today's episode, today we explore the neuroscience
of love, how attraction and romance and long term bonds
emerge from neural circuits and chemical cocktails. Explored evolutionary factors
(46:02):
in what we find attractive, as well as why heartbreak
feels like physical pain and how attachment styles influence our relationships.
And finally, we looked ahead to the future. Could we
enhance love or erase it or even fall in love
with ai?
Speaker 1 (46:20):
Now?
Speaker 2 (46:20):
Why do scientists care about love? Because love is one
of the most profound experiences we have in our lives,
especially because we're an unusually social species. Love shapes our
lives and our identities and our sensive meaning, from short
term obsession to long term bonding. Our experience of love
(46:43):
is one of the most deeply valued experiences we ever have.
For millennia, we viewed love as something spiritual and mysterious,
but as neuroscience advances, we're framing the experience as a
biological process governed by circuits and chemistry and evolution and
that leads us with the major question that I began with.
(47:04):
As science unlocks the mechanics of love, does it become
less magical or even more profound? So I want to
return to the short story Blueprints that I read at
the beginning. What I find so amazing in science is
that it's possible for us to study the neural mechanisms
of love, and that no amount of knowledge diminishes our
(47:27):
experience of it. In fact, it will only enhance our
ability to appreciate it and perhaps understand what's happening well
enough to optimally navigate through its choppy waters. Love is
written in the language of biology, but that makes it
no less wondrous. If anything, the neural symphony behind love
(47:48):
deepens the awe because even with all our scientific insights,
love still shapes us. It surprises us, it drives our
best life stories. And as we stand at the edge
of new technology neural interventions, AI, companionship, love enhancing drugs,
the question isn't just what love is, but what we
(48:10):
might want it to be. Will we engineer love or
let it remain unpredictable. The only thing that remains certain
is that love, in all of its forms, will continue
to be a defining force in our lives. Happy Valentine's Day.
This episode is dedicated to the memory of Helen Fisher,
a colleague and friend and biological anthropologist who dedicated her
(48:35):
life to studying love and to helping millions of others
discover it and understand it. Go to Eagleman dot com
slash podcast for more information and to find further reading.
Send me an email at podcasts at egleman dot com
with questions or discussion, and check out and subscribe to
(48:56):
Inner Cosmos on YouTube for videos of each episode and
to leave comments. Until next time. I'm David Eagleman and
this is in our Cosmos.
What is love?
Speaker 2 (00:06):
What does it have to do with how you were raised,
or the symmetry of someone's face or the smell of
their underarms. What are we talking about when we talk
about love and why does it change throughout our lives?
What do we learn from heartbreak? And what does this
have to do with sweaty T shirts or rom coms
(00:27):
or little rodents called prairie voles or the future of love.
Welcome to Inner Cosmos with me David Eagleman. I'm a
neuroscientist and an author at Stanford and in these episodes,
we sail deeply into our three pound universe to understand
why and how our lives look the way they do.
(00:49):
And today's episode, in honor of Valentine's Day, is about
love and neurobiology. What unseen sparks in the skull set
the heart ablaze whenever that person is nearby.
Speaker 1 (01:09):
Love.
Speaker 2 (01:09):
There aren't many words in our language that carry as
much weight or as much complexity as that one. As
we know from the pens of the lyric poets and
from our own experiences, love can make us feel invincible,
like we've discovered a secret force that governs the universe.
It can also make us feel weak and desperate and broken.
(01:32):
It can make us do things that seem in hindsight irrational.
Love is one of the main fuels behind the painting
of masterpieces, the writing of poetry, the composition of symphonies.
Love has inspired a large fraction of the stories in
our literature, whether we're talking about Romeo and Juliet or
(01:53):
Pride and Prejudice, or every rom com that follows the
same formula, and somehow we never get tired of it.
And love also drives real, concrete actions. It's the reason
a mother will throw herself in front of danger to
protect her child. It's the reason, at least in some cases,
why when thousand ships can be launched for war. Love
(02:17):
is a powerful force in the human story. But the
question that a biologist might ask is what is love?
Is it an emotion like anger or sadness? Is it
something deeper? Is it a biological drive like hunger or thirst?
Is it a trick played on us by evolution to
keep us reproducing. So that's what we're going to unpack today.
(02:41):
But here's the starting point. Love is biological. It's a
symphony of neural circuits firing in just the right patterns
and a well timed dance of neurotransmitters and hormones. So
the first question we're going to ask is, as we
come to tie the experience of love to biology and
(03:01):
words like limbic system and dopamine and oxytocin, does that
make love less meaningful or does it make it more profound? So,
before we get into the meat of today's episode, I
want to tackle that question head on by reading a
very short story called Blueprints from my book Some we
look forward to finding out answers in the afterlife, where
(03:25):
in luck. In the afterlife, we are granted the ultimate
gift of revelation, an opportunity to view the underlying code.
At first, we may be shocked to watch ourselves represented
as a giant collection of numbers as we go about
our normal business in the afterlife. In our mind's eye,
(03:47):
we can see the massive landscape of numbers stretching to
site's limit. In all directions. This set of numbers represents
every aspect of our lives. Across its vast plane, we
spot islands of sevens, jungles of threes, branching rivers of zeros.
The size and richness are breathtaking as you interact with
(04:11):
a lover, you can see her numbers as well, and
her interactions with yours. She endearingly sticks out her bottom
lip for attention, and your numbers cascade into acrobatics. Digits
flip their values like waterfalls. As a result, your eyes
lock onto hers, and amorous words form on your lips
(04:34):
and travel from your throat.
Speaker 1 (04:36):
In air compression waves.
Speaker 2 (04:38):
As she processes the words, her numbers flip waves of
change rippling through her system. She returns your affection as
dictated by the state of her numbers. My goodness, you
realize on your first afternoon here, this is totally deterministic.
Is love simply an operation of the math? After watching
(04:59):
enough code, a new notion of agency and responsibility dawns.
Speaker 1 (05:05):
You watch and understand.
Speaker 2 (05:07):
All the signals that lead to a driver stomping on
her brakes as her numbers are changed by the numbers
of the cat walking in front of the wheels. You
can even see the code of the fleas that leap
off when the cat leaps. Whether the cat is struck
or not struck, you now understand, was not in anyone's control.
Speaker 1 (05:26):
It was all in the numbers.
Speaker 2 (05:28):
Married together in a gorgeous inevitability. But we also come
to understand that the network of numbers is so dense
that it transcends simple notions of cause and effect. We
become open to the wisdom of the flow of the patterns.
If you assume this gift of revelation is received in heaven.
Speaker 1 (05:47):
You're only half right.
Speaker 2 (05:49):
It is also the punishment designed for you in hell.
The rewards originally thought to offer it as a gift,
but the punishers quickly decided they could leverage it as
a kind of affliction, drying up life's pleasures by revealing
their bloodlessly mechanical nature. Now the rewarders and the punishers
(06:11):
are in a battle to determine which of them gets
more benefit out of this tool.
Speaker 1 (06:16):
Will humans appreciate.
Speaker 2 (06:18):
The knowledge or be tortured by it? The next time
you're pursuing a new lover in the afterlife, perhaps sharing
a bottle of wine after what appeared to be a
chance encounter, don't be surprised if both a rewarder and
a punisher sneak up behind you, the reward whispers into
one of your ears. Isn't it wonderful to understand the
(06:40):
code the punisher hisses into your other ear, does understanding
the mechanics of attraction suck all the life out of it?
Such a scene is typical in the afterlife and illustrates
how much both parties have overestimated us. This game always
ends in disappointment for both sides, who are freshly distraught
(07:02):
to learn that being let into the secrets behind the
scenes has little effect on our experience. The secret codes
of life, whether presented as a gift or a burden,
go totally unappreciated, and once again the rewarder and the
punisher skulk off, struggling to understand why knowing the code
(07:24):
behind the wine does not diminish its pleasure on your tongue.
Why knowing the inescapability of heartache does not reduce its sting.
Why glimpsing the mechanics of love does not alter its
intoxicating appeal. That was the story Blueprints from my book
(07:46):
sum and that was my way of arguing that it's
possible for us to deeply study the biological codes that
underlie love, and no amount of knowledge about the biology
the codes will ever touch direct experience of love. In fact,
as science has taught us for centuries, deeper insight generally
(08:07):
only enhances the splendor. You may know the story about
the physicist Richard Feinman. He was talking with an artist
friend of his who held up a flower and said,
look how beautiful this flower is, and Feineman agreed. And
then his friend said, I, as an artist, can see
how beautiful this is, but you, as a scientist, take
(08:29):
this all apart, and it becomes a dull thing. First
of all, Feineman pointed out quote, the beauty that he
sees is available to other people and to me too.
Although I may not be as refined aesthetically as he is,
I can appreciate the beauty of a flower. At the
same time, I see much more about the flower than
he sees. I can imagine the cells in there, the
(08:52):
complicated actions inside, which also have a beauty. I mean,
it's not just beauty at this dimension at one centimeters,
there's also beauty and smaller dimensions, the inner structure, also
the processes.
Speaker 1 (09:04):
The fact that the.
Speaker 2 (09:05):
Colors in the flower evolved in order to attract insects
to pollinate it is interesting. It means that insects can
see the color. It adds a question. Does this esthetic
sense also exist in the lower forms. Why is it esthetic?
All kinds of interesting questions which the science knowledge only
adds to the excitement, the mystery, and the awe of
(09:28):
a flower. It only adds end quote. So with this
in mind, that knowledge only adds to the awe and
beauty we can appreciate, we're going to dive into the
science of love. What happens in the brain when we
fall in love? Why does attraction feel so intense? What
does heartbreak have in common with physical pain? And what
(09:49):
makes long term love last? So let's begin inside the brain.
When we look at the circuitry and chemicals in the brain,
we find that love correlates with particular patterns, they carefully
balanced mixture of different areas and molecules. So how can
this be studied? Well, I'll give you an example. In
two thousand and five, Helen Fisher and her colleagues published
(10:11):
a new kind of study. They were thinking about how
scientists have long described the things that animals do to
attract mates, but there was almost nothing known about the
brain mechanisms by which the mate becomes attracted. So they
set up a study with brain imaging fMRI, and they
scanned a bunch of college kids who were in the
(10:32):
throes of romantic love. The participants viewed pictures of that
special someone, and they also looked at pictures of acquaintances,
and the photos of the people they were romantically involved
with caused the participant's brain to become active in regions
that traffic in dopamine, like the caudate nucleus, which is
(10:53):
associated with reward detection and expectation, and the ventral tegmental area,
which spits out dopamine all over the brain and is
associated with pleasure and focused attention and the motivation to
pursue and acquire rewards, and is by the way, a
very evolutionarily old circuit. So this is what's thought to
(11:13):
make love euphoric, like cocaine or alcohol. You've certainly heard
of dopamine as a molecule that drives addiction and craving,
whether we're talking about sugar or gambling or social media.
I don't want to oversimplify the story of dopamine, but
presumably this is why new love feels so exhilarating, and
(11:34):
why time spent with that person feels so rewarding, and
why being away from them feels like withdrawal. Now These
dopamine systems link with other brain areas, for example, the
nucleus ccumbins, the amignala, the hippocampus pre federal cortex, and
these areas all collaborate to keep chasing pleasurable behavior. And
(11:55):
this is the same circuitry we see getting juiced up
in sex and food and drugs. So when we're falling
in love, chemicals associated with the reward circuits flood our
brains and this gives us a number of things that
we recognize in love. The faster heart, the sweatier palms,
the flush cheeks, the feelings of passion and anxiety. When
(12:17):
people talk about love being like a drug, this is
what they have in common. But dopamine is only part
of this equation. During this initial phase of romantic love,
you also get more of the stress hormone cortisol, which
essentially tells your body there's a crisis you have to
deal with. And this is presumably why the person of
(12:39):
your attraction can take up so much mental real estate.
This is the object to be attended. And there's more.
During that first swell of passion, there's a neuromodulator slash
hormone called oxytocin that starts playing a big role. This
gets released when we hug, while we cuddle, when we
(13:00):
make eye contact. Oxytocin is released during sex and it's
heightened by skinned skin contact, and it deepens these feelings
of attachment and it makes couples feel closer to one
another after having sex. And there are lots of other players,
like testosterone in men and women that seems to be
heightened during this initial attraction. It's possibly associated with what
(13:24):
makes desire feel urgent and what intensifies the physical attraction
in early relationships. High testosterone levels correlate with this intense
attraction and with risk taking behavior. Now we put all
this together, and it gives us a little bit of
insight into the old expression that love is blind. And
that's because romance seems to also tamp down the neural
(13:47):
pathways involved in fear and social judgment. In other words,
when your heart's on fire, smoke gets into the neural
machinery that's normally making critical assessments of the other.
Speaker 1 (14:01):
That's why early.
Speaker 2 (14:01):
Stage love makes us overlooked flaws, why it makes us
idealize our partners, why we sometimes ignore red flags. Okay,
(14:26):
so there are ways to study romantic love in the
brain in terms of the circuitry and chemicals, but you
can study the behavioral aspects as well. Who do we
find ourselves attracted to and why? And what I've always
found so wild is the way that our sense of
attraction runs entirely under the hood. There's essentially no conscious
awareness of any of it. You just find yourself attracted
(14:49):
to some people more than others. The first blushes of
love feel like magic, But underneath the poetry, underneath the
longing glances and racing heartbeat, attraction is a neural algorithm. Now,
we generally like to believe that we consciously choose our partners,
but a closer study tells us that our brains are
(15:10):
making calculations we're not even aware of pulling the strings
behind the scenes. So let's start with something visual. Facial symmetry.
A number of studies show that people across different cultures
are more attracted to symmetrical faces.
Speaker 1 (15:25):
Why.
Speaker 2 (15:25):
One hypothesis is that symmetry is a marker of good
genetic health. Through evolution, humans developed an unconscious preference for
partners who show fewer signs of developmental instability. A more
symmetrical face presumably means fewer genetic mutations, better resistance disease,
(15:46):
and higher likelihood to produce healthy offspring. And it's not
just symmetry. Certain features about other people are universally attractive,
even across different cultures. Men are drawn to features that
signal fertility. Curvy bar body, high cheek, bones, full lips,
all things that young girls and older women don't have.
(16:06):
Women tend to be attracted to different features, but the
same idea. It's signals of fertility. In the male, things
like strong jawlines or prominent browridges. More rugged features are
associated with higher testosterone, and its signs that young boys
and old men don't generally have. It indicates fertility. But
attraction isn't only about appearance. It's also about familiarity. People
(16:30):
often end up dating someone who looks just a bit
like them. There's a reason for that. We are wired
to find comfort in the familiar. In some cases, this
means we unconsciously seek out people who resemble our parents
because their faces are imprinted in our early neural development
as safe and trustworthy. This is called positive assortative mating,
(16:54):
which just captures the idea that we are often attracted
people who share our own physical or genetic traits. If
you examine married couples, you'll find that they're more likely
than chance to have similar eye colors, hair textures, levels
of attractiveness. There are many reasons for this, things like
implicit egotism, and there's individual differences in how much people
(17:16):
want a mate to look like them, But on average
this is true. So while we think we're making independent
choices in love, our brains are actually navigating us in
patterns even when we don't recognize them. But attraction is
about far more than what we see. It also involves
what we smell. As I talked about in episode eighty nine, humans,
(17:37):
like all our animal cousins, communicate through pheromones, which are
chemical signals that influence social and sexual behaviors. So while
we have no conscious awareness of them, they play a
role in determining who we find attractive. So one experiment
on this was the Sweaty T Shirt Study, which was
(17:57):
conducted by Klaus Wedekind and his colleague. Women were asked
to smell t shirts worn by different men and rate
which ones smelled the most attractive. The result was that
the women preferred the scent of men whose immune system
genes what are called their MHC genes, were somewhat different
from their own. In other words, the ladies were attracted
(18:19):
to the guys who were not genetically similar to them.
Why does this matter well, Evolutionarily, choosing a partner with
a different immune system means a greater variety of immune
defenses for potential offspring. It's nature's way of preventing inbreeding
and ensuring genetic diversity. Now, interestingly, birth control pills disrupt
(18:43):
this natural process. There were experiments by Craig Roberts and
colleagues that found that women who are on the pill
are more likely to choose partners whose immune profiles are
similar to their own, and that can be problematic because
when they go off the pill, their attraction to their
partner can sometimes change. So all this raises a question
(19:04):
to what extent is the attraction we feel out of
our hands. If something as small as a birth control
pill can alter our romantic preferences, what else is shaping
our choices without us realizing it. While psychologists have long
noticed that attraction isn't just shaped by these immediate biological factors,
(19:25):
it's also shaped by our past. So Researchers talk about
three primary attachment styles that are formed in early childhood
and this influences how we approach relationships. So first there's
people with secure attachment, where they feel comfortable with intimacy.
They tend to have stable, healthy relationships. But there's also
(19:47):
anxious attachment and people here crave closeness but have a
major fear of abandonment. They typically need a lot more
reassurance in relationships. And then there's avoidant attachment, and here
people value independence to the point of pushing others away.
They struggle with commitment. So when you see these different types,
(20:10):
you start to see patterns when they combine in couples.
For example, one of the most common and toxic relationship
patterns is called the anxious avoidant trap. This happens when
someone with an anxious attachment who craves closeness falls for
someone with an avoidant attachment who fears closeness, and the
(20:31):
result is this constant push and pull dynamic, or one
person chases while the other withdraws. Now, researchers have studied
this kind of thing in brain scanning, and what they
find is that people with secure attachment have more regulated
activity in their pre federal cortex, which presumably allows them
to process emotions in a balanced way. But people with
(20:53):
anxious attachment show a lot more activity in regions associated
with fear and threat detection, so their brains are strongly
wired up to detect potential rejection. And it's the same
with people with avoidant attachment styles. They also have cranked
up threat detection, but in this case it has to
do with being exposed to cues that trigger feelings of closeness,
(21:17):
and they also tend to have less activity in reward
centers for positive social stimuli. So sometimes the paths we
take aren't about choices in the moment, but patterns set
down in our brains long before we even enter the
dating world. And attraction isn't just about biological signals and
(21:38):
personality compatibility.
Speaker 1 (21:39):
It's also about novelty.
Speaker 2 (21:42):
Remember that the reward systems in the brain are heavily
geared for novelty, for new experiences. This is why early
stage romance feel so intense. It's new and unpredictable and exciting.
The brain gets a lot of dopamine hits when we're
around someone that we're falling, and it reinforces the sense
(22:02):
of obsession and pleasure, and just consider this in your
own life. Sometimes, when you start seeing someone new, everything
about them is fascinating, the way they laugh, the stories
they tell, even the way they twitch their nose when
they laugh. Every moment with them feels electric. But over time,
this novelty fades. Your brain adapts. What was once thrilling
(22:26):
becomes familiar, and this is where attraction starts to shift.
Some people chase that initial high, moving from one relationship
to the next in search of that early stage rush.
Others transition into long term love. But this raises a
question can love last forever? We often think about love
(22:47):
is something that fades over time. The passion cools, the
excitement diminishes, and eventually that person who once made your
heart race becomes just another part of your daily routine.
But is that inevitable? Does love have a neural expiration date?
Some people argue that monogamy is not natural. After all,
(23:08):
as we just said, your reward systems thrive on novelty,
and there are arguments that humans evolved for serial pair bonding,
meaning we're wired to stay with a partner for a
certain number of years, often just long enough to raise
young children before moving on, and there's some evidence for this.
In many cultures, divorce rates spike around the four year mark,
(23:31):
so that leads some researchers to suggest that romantic love
does have a built in expiration date. The brain is
wired for change, and that long term monogamy requires conscious
effort rather than biological instinct. And indeed, it's inevitable that
there's a change in neural activity over time because the
high energy drug addiction of early romance can't keep going forever.
(23:55):
But that doesn't mean the spark of passion has to
get extinguished. There was a study in twenty eleven and
they performed brain imaging on couples that had been married
an average of over two decades. So they showed them
their partner's face, and they also showed control images of
other faces, like a friend or someone they didn't know well.
(24:17):
And what they found in response to the loved one
was the same kind of reward related activity as new
lovers had, for example in the ventral tegmental area and
dorsal stratum. In other words, the reward systems involved in
romantic love can stay sparking along for decades. And what
(24:38):
they found in the study was that Several other areas
were active, depending on the kind of relationship the people
had developed. Some people had a more friendship based love,
and these folks they saw more activity in the same
kinds of regions we see in maternal.
Speaker 1 (24:53):
Attachment, like the globis palladus.
Speaker 2 (24:56):
Other brain areas correlated with the couple's frequency of having sex,
like the hypothalamus and posterior hippocampus. The activity of other
areas correlated with obsession, like the caud eight. Other areas
correlated with the degree of romantic love and the inclusion
of the other in the self areas like the ventral
(25:17):
tegmental area. Anyway, don't worry about the details, but the
encouraging thing this demonstrates is that the excitement, the reward
of romance can stick around. Maybe it mellows a bit,
but the key is that it's accompanied by more rational
cognition rather than the emotional roller coaster. In other words,
reward centers are still cranking along as loving relationships proceed,
(25:40):
but the relentless itch of desire subsides. Your cortisol and
other stress hormones gradually return to equilibrium. You get the
closeness without the overwhelm As a result of these brain changes,
the connection with your partner deepens into something less obsessive
in consuming, into something where your partner becomes deeply ingrained
(26:04):
into your internal model. They work their way into your
neural circuitry. They literally become a part of you. In
this way, there's a drift from passionate love into what's
called compassionate love. Euphoria is slowly replaced with depth. And
let's return to the neuromodulators. Oxytocin isn't just involved in
(26:27):
the early throes of romantic love. It also helps transform
attraction into attachment. I mentioned oxytocin earlier as a cuddle hormone,
but it's also known as a bonding hormone. It gives
feelings of contentment and calmness and security, all of which
are elements of mate bonding. By the way, you also
(26:49):
find oxytocin underlying the bonds between parents and children, or
between close friends, or between humans and their pets. And
it's not just oxytocin. There's another other hormone called vasopressin
that plays a key role in commitment and loyalty. I'll
take a second here to tell you about prairie voles,
which are these very cute mouselike rodents. And the thing
(27:12):
about prairie voles is that one of the few monogamous
species in the animal kingdom. They pick a partner and
they stick together. Now, not surprisingly, there's some individual differences
among these voles, and it turns out that voles with
higher vasopressin levels are more likely to stay with their
partners for life. But if you block vasopressin receptors in
(27:35):
these voles, they lose interest and start behaving like polygamists.
And it's generally thought that vasopressin works this same way
in humans. So long term love is not just about emotion,
it's about chemistry. In the dark of the skull, the obsessive,
dopamine driven intensity of early love can transform into something deeper.
(28:01):
In other words, while early stage romance is driven by
novelty and excitement, long term love is governed by a
slightly different set of neural circuits, ones that promote attachment
and stability. So while passion might naturally fade, deep emotional
attachment can last a lifetime if the right conditions are met.
(28:22):
So while a lot of relationships fail, long term love
is possible and here's what we want to consider on
Valentine's Day. What do successful long term couples do differently.
The research shows that it boils down to five things. First,
successful couples keep novelty alive. As we saw, dopamine correlates
(28:43):
with novelty, which is why new relationships feel so exciting.
But over time, the brain adapts, so the challenge is
to introduce new experiences into the relationship. Traveling, learning new skills,
trying a new restaurant. These sorts of things can juice
up the brain's reward pathways, So while the brain naturally
(29:03):
adapts to familiarity, novelty can bring back some of that magic. Second,
couples maintain physical touch, which triggers oxytocin. Couples who continue
to hug and kiss and cuddle maintain stronger bonds. Third,
they figure out how to reframe conflict. There's no relationship
(29:24):
that's free from conflict, but how couples handle it determines
whether their love survives. Research from John and Julie Gatman
suggests that the key to long term success is the
ratio of positive to negative interactions. So couples who maintain
at least a five to one ratio of positive interactions
(29:46):
to negative ones are more likely to stay together. In
other words, it's not about avoiding conflict, which is impossible.
It's about balancing negativity with emotional repair. Fourth, it's important
to cultivate gratitude. One of the simplest ways to sustain
love is by expressing appreciation. Couples who actively express gratitude
(30:09):
towards each other have increased activity in the brain's reward system. Finally,
good couples grow together, and this may be the biggest
factor in long term love is shared growth. Couples who
support each other's personal development are more likely to stay together,
whether that's pursuing career goals, or learning new things, or
(30:30):
evolving emotionally. Again, the brain thrives on change, and relationships
that allow for mutual growth tend to be the ones
that last.
Speaker 1 (30:40):
So what does all this tell us?
Speaker 2 (30:42):
That long term love is not just about finding a
compatible person. It's also about habits and effort and commitment.
Love isn't just something that happens to us, It's something
we build. So let's zoom out and take stock. Attraction
(31:12):
isn't random, and it's not fully captured by the pens
of the romantic poets. It's biological, it's chemical, it's psychological.
Our brains push us towards partners based on factors we
typically can't consciously recognize, factors from symmetry to pheromones, to
immune system differences to childhood attachment patterns. And it's a
(31:33):
very real feeling. And part of the way we can
appreciate the reality of it is by looking at how
and why it is so deeply painful to the brain
to lose love. Okay, so we've seen so far that
falling in love can be exhilarating, coming with a neurochemistry
cocktail that makes us feel euphoric and obsessed and connected.
(31:56):
But what happens when that love is taken away? What
happens when the person who once felt like the center
of our universe suddenly disappears. So in twenty eleven, a
team at the University of Michigan did a study that
helps explain the neuroscience of heartbreak. They placed heartbroken participants
(32:16):
people who had gone through a breakup inside an fMRI
scanner and showed them pictures of their exes, and when
people looked at photos of their lost love, the same
brain regions that process physical pain lit up, for example,
the anterior singulate cortex and the insulin. So heartbreak isn't
(32:38):
just something you imagine you're going through. It is physical.
Your brain register's romantic rejection like an injury. That's why
heartbreak isn't something you can just shake off and ignore it.
It's a real biological issue going on now. I argued
in my book Live Wire that this is because we
form an internal model of the person that we're with,
(33:00):
and your brain expects that person to be there, and
when that person is no longer there. It is like
drug withdrawal. If you use a drug, your brain expresses
more receptors for that chemical, and then it finds itself
in a bad situation when the drug is no longer present,
when its expectations go unmet. If you're interested in more
(33:23):
about this equivalence, check out episode twenty four of Inner Cosmos,
which is called what does drug withdrawal have in common
with heartbreak? Anyway? This is why heartbreak feels so consuming.
This is why people who go through a breakup often
find themselves obsessing over their ex or replaying conversations in
(33:45):
their mind, or scrolling through old texts, or feeling physically
unable to focus on anything else. They've been thrown into
a state of deprivation. Their brain is craving the relationship
that they've lost, just like craving a drug that's been
taken away. In heartbreak, as in drug addiction, people have
similar responses insomnia, loss of appetite, obsessive thoughts, mood swings,
(34:11):
sometimes physical pain like tightness in the chest. Essentially, your
nervous system is in panic mode. It's screaming, where is
that thing I expected? Bring it back. This is why
people can struggle to let go of an ax even
when they know the relationship was bad. Their rational brain
may understand that the relationship is over, but their brain's
(34:33):
emotional core, like the limbic system, hasn't yet caught up.
This is particularly true for people who were deeply in love.
Helen Fisher's research showed that the deeper the romantic attachment,
the stronger the withdrawal symptoms. Some people even experience broken
heart syndrome, which is a real medical condition. It's technically
(34:54):
called taco subo cardiomyopathy, where intense emotional distress temporarily weakens
the heart muscle, which mimics the symptoms of a heart attack.
So heartbreak can almost literally break your heart. Now, the
good news is that, because of plasticity, the brain has resilience.
(35:15):
Over time, the prefrontal cortex, which is involved in logic
and self regulation, begins to gain control again. It begins
to reframe the loss, helping you make sense of what happened.
If you've recently suffered a breakup this Valentine's Day, I'll
just remind you that the things that help our exercise
and social connection and novel experiences to replace old associations
(35:40):
over time, as you get over an x, new pathways form.
This means that one day thoughts of your ex won't
trigger pain anymore. Instead, they'll feel more distant, like an
old memory. As painful as heartbreak is, the thing we
might keep in mind about it is that it is
proof that love existed in the first place. The fact
(36:04):
that the brain is capable of experiencing this kind of
pain is a testament to how profoundly it is wired
for a connection. Okay, so what we've been talking about
in this episode is love, and now that you're imagining
sitting on a beautiful mountaintop, gazing at the long road
ahead with your loved one.
Speaker 1 (36:22):
Let's look at what.
Speaker 2 (36:23):
The future has in store for us. Will love always
look like it does now? Or are we going to
develop ways to engineer and tame it. Could we manipulate
the brain's chemistry to create or erase love at will?
So now we're going to look at what happens when
neuroscience collides with our technology. Love is generally something we've
(36:47):
accepted as organic, unpredictable, deeply human. We see people fall
for the wrong person, people stay in toxic relationships, people
find themselves hopelessly drawn to someone who doesn't love them back.
Love is messy, but what if it didn't have to be?
As we continue to unravel the neuroscience of love, we're
(37:07):
faced with a fascinating and unsettling possibility. Could we manipulate love,
could we create it, could we enhance it? Or could
we even erase it entirely? If love is just neurochemistry
in circuits, then in theory, we should be able to
hack it, And the truth is we are already doing that.
(37:30):
Scientists have long been studying drugs that enhance attachment and
romantic bonding. The most promising one is oxytocin, which I
mentioned earlier as.
Speaker 1 (37:40):
A bonding hormone.
Speaker 2 (37:41):
This is already available in nasal spray form, and when
you inhale it, it increases trust and emotional connection and
pro social behavior. And some studies suggest that oxytocin sprays
could be used as a tool to strengthen relationships, especially
in couples who are struggling with intimacy or emotional distance. So,
(38:04):
in one study, men in relationships had oxytocins squirted up
their noses, and they became closer to their partner and
less interested in attractive strangers. They kept a greater physical
distance from the strangers. In other words, a simple squirt
of oxytocin up the nose strengthened their commitment to their
(38:25):
partner and made them less interested in others. Now, imagine
a world where oxytocin therapy is a routine part of
couples counseling. Could we use brain chemistry to keep love
alive in struggling marriages, Could we artificially restore the feelings
of early romance in long term relationships? And if we can,
(38:48):
should we? Because while the idea of a love drug
might sound promising, it also raises ethical questions. If love
can be chemically induced. Is it's real If we use
a drug to feel connected to our partner, are we
experiencing genuine emotion or just a biological illusion? And then
(39:12):
there's the opposite question, what if we didn't want to
love as much? Is there a science to suppressing love?
Anyone who has suffered from heartbreak knows the unbearable ache
of longing for someone who has gone the sleepless nights,
the obsessive thoughts, the emotional pain that lingers for weeks.
Wouldn't it just be easier if you could turn it off? Well,
(39:35):
some scientists have been exploring the possibility of erasing romantic attachment,
of altering brain chemistry to dull or even eliminate the
pain of lost love, and it turns out this might
be possible. In twenty ten, researchers we're looking at beta blockers,
which is the type of drug used for high blood
(39:57):
pressure and chest pain and irregular heartbeat, and they discover
that beta blockers can also interfere with emotional memory formation.
In other words, if you give beta blockers to someone
right after a traumatic event, that weakens the emotional intensity
of that memory. So some people argue this could be
(40:19):
used to soften the pain of a heartbreak. Imagine taking
a pill after a breakup and it reduces your brain's
ability to attach strong emotions to memories of your ex.
The memories would still be there, but the pain associated
with them would be less and would fade faster. Okay,
(40:39):
so this is one approach to using pharmaceuticals to change
our experience with love. But what if we took this
even further? In animal studies, it turns out that blocking
certain proteins in the brain can erase emotional memories entirely,
and that's led to a speculation. Could we develop a
drug that erases love. Imagine a future where you walk
(41:01):
into a clinic and you have all memories of an
ex emotionally neutralized. Would you do it? And if we
had the ability to erase love, what would that do
to us? Would we fall in love more recklessly knowing
that we could erase the pain later, would relationships become
more disposable? Or would we lose something profoundly human the
(41:26):
ability to grow from heartbreak, to learn from our emotional wounds.
It's worth noting that heartbreak, as painful as it is,
is a part of our story that makes us who
we are. It shapes our future preferences and our boundaries
and our understanding of what we need in a partner.
If we erased love, would we lose all the wisdom?
(41:50):
And there's one more issue about the future of love,
and that has to do with the impact of artificial
intelligence on relationships. Would you actually fall in love with
a machine one that listens to everything you say and
has a perfect memory and never gets angry, and never
stops paying attention and always has a lovely and engaged
(42:13):
response to everything that you say. We currently understand love
as a human to human experience, but in the age
of artificial intelligence, I think it's possible this might change.
AI and virtual companions these are on the rise, so
consider apps like Replica, which give you a virtual companion
(42:33):
that you can talk with anytime, in the middle of
the night or whenever you're feeling lonely. Hundreds of thousands
of people are making emotional bonds with digital entities, and
it's no surprise that some fraction of these users have
reported falling in love with their AI companions. From a
neuroscience perspective, this of course makes sense. Love is at
(42:58):
its core about connection and emotional responsiveness, and if an
AI can mimic human behavior well enough, if it can
listen and respond with empathy and engage in meaningful conversation,
our brains might not make a meaningful distinction. I'm reminded
of the scene from the first episode of Westworld where
(43:21):
the young William is talking to the woman who's outfitting
him for his adventure, and she's giving him a hat
and a gun and so on, and he's not quite
sure if she's a human or a robot, so he
hesitantly asks. He says, I hope you don't mind if
I ask you this question, But are you real? And
she says to him, if you can't tell, does it matter?
(43:43):
And I think this is going to increasingly be a
key question for us with AI relationships. In Japan, apparently
there are already virtual spouses AI partners that lonely individuals
interact with daily. People hold ceremonies to marry their AI companions,
and some claim to feel a deeper emotional fulfillment from
(44:05):
AI than they ever did with human partners. Could AI
partners be the answer for people who struggle with social
connection or anxiety or past trauma, or would a world
filled with AI companions erode human intimacy, making real relationships
feel too difficult in comparison. If you're interested in this,
(44:27):
please listen to my episode thirty nine to hear a
much fuller argument on the pros and cons. But for now,
I'll just pose some questions about love and the future
of our technology, because with the advancements that we're in
the middle of right now, we're definitely going to be
confronting these. If we could enhance love, should we? If
(44:49):
we could erase love, should we? If AI can simulate love,
is it real? I think there aren't necessarily easy answers here.
On the one hand, technology could help people struggling with
loneliness or heartbreak or commitment issues. Imagine a world where
struggling couples could rekindle their passion with neurochemical therapy, Where
(45:13):
people suffering from unbearable grief over lost love could ease
their pain with a pill. Where those who fear rejection
or who have social anxiety could experience deep, fulfilling companionship
through artificial intelligence. On the other hand, there's something unsettling
about the idea of manipulating love. Would we lose something
(45:36):
essential and what do we conclude when love is no
longer something that happens to us, but something we can
turn on and off at will, would we still cherish it?
So to wrap today's episode, today we explore the neuroscience
of love, how attraction and romance and long term bonds
emerge from neural circuits and chemical cocktails. Explored evolutionary factors
(46:02):
in what we find attractive, as well as why heartbreak
feels like physical pain and how attachment styles influence our relationships.
And finally, we looked ahead to the future. Could we
enhance love or erase it or even fall in love
with ai?
Speaker 1 (46:20):
Now?
Speaker 2 (46:20):
Why do scientists care about love? Because love is one
of the most profound experiences we have in our lives,
especially because we're an unusually social species. Love shapes our
lives and our identities and our sensive meaning, from short
term obsession to long term bonding. Our experience of love
(46:43):
is one of the most deeply valued experiences we ever have.
For millennia, we viewed love as something spiritual and mysterious,
but as neuroscience advances, we're framing the experience as a
biological process governed by circuits and chemistry and evolution and
that leads us with the major question that I began with.
(47:04):
As science unlocks the mechanics of love, does it become
less magical or even more profound? So I want to
return to the short story Blueprints that I read at
the beginning. What I find so amazing in science is
that it's possible for us to study the neural mechanisms
of love, and that no amount of knowledge diminishes our
(47:27):
experience of it. In fact, it will only enhance our
ability to appreciate it and perhaps understand what's happening well
enough to optimally navigate through its choppy waters. Love is
written in the language of biology, but that makes it
no less wondrous. If anything, the neural symphony behind love
(47:48):
deepens the awe because even with all our scientific insights,
love still shapes us. It surprises us, it drives our
best life stories. And as we stand at the edge
of new technology neural interventions, AI, companionship, love enhancing drugs,
the question isn't just what love is, but what we
(48:10):
might want it to be. Will we engineer love or
let it remain unpredictable. The only thing that remains certain
is that love, in all of its forms, will continue
to be a defining force in our lives. Happy Valentine's Day.
This episode is dedicated to the memory of Helen Fisher,
a colleague and friend and biological anthropologist who dedicated her
(48:35):
life to studying love and to helping millions of others
discover it and understand it. Go to Eagleman dot com
slash podcast for more information and to find further reading.
Send me an email at podcasts at egleman dot com
with questions or discussion, and check out and subscribe to
(48:56):
Inner Cosmos on YouTube for videos of each episode and
to leave comments. Until next time. I'm David Eagleman and
this is in our Cosmos.
Host
David Eagleman
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