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