The Science of Love, Desire and Attachment

**Andrew D. Huberman** (0:00)
Welcome to the Huberman Lab podcast, where we discuss science and science-based tools for everyday life.
I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today, we are going to talk about the psychology and the biology of desire, love and attachment. Today happens to be Valentine's Day, 2022 However, the themes we are going to discuss pertain to desire, love and attachment on any given day. And indeed, the mechanisms we are going to discuss almost certainly were at play thousands of years ago, hundreds of years ago, and no doubt will still be at play in our minds and in our bodies and in our psychologies for the decades, centuries and thousands of years to come. Indeed, today I want to focus on core mechanisms that lead individuals to seek out other individuals with whom to mate with, with whom to have children with or not, with whom to enter short or long-term relationships with and perhaps to end those relationships or to seek relationships on the side, so-called infidelity. I'm certainly not going to encourage or discourage any of these behaviors. I'm simply going to cover the peer reviewed scientific data on all these aspects of desire, love and attachment. I'm going to discuss how our childhood attachment styles, as they're called, influence our adult attachment styles. Yes, you heard that right. How we attached or did not attach to primary caregivers in our childhood has much to do with how we attach or fail to attach to romantic partners as adults. Because the same neural circuits, the neurons and their connections in the brain and body that underlie attachment between infant and caregiver, between toddler and parent or other caregiver, and during adolescence and in our teenage years are repurposed for adult romantic attachments. I know that might be a little eerie to think about, but indeed that is true. Now the fortunate thing is that regardless of our childhood attachment styles and experiences, the neural circuits for desire, love and attachment are quite plastic. They are amenable to change in response to both what we think and what we feel as well as what we do. However, all three aspects that we're discussing today, desire, love and attachment are also strongly biologically driven. We're going to talk about biological mechanisms such as hormones, biological mechanisms such as neurochemicals, things like dopamine, oxytocin and serotonin and neural circuits, brain areas and indeed areas of the body that interact with the brain that control whether or not we desire somebody or not, whether or not we lose or increase our desire for somebody over time, whether or not we fall in love, what love means, and whether or not the relationships we form continue to include the elements of desire and love over time or not. In order to illustrate just how powerfully our biology can shape our perception of the attractiveness of other people, I want to share with you the results of a couple of studies. Both studies explore how people rate other people's attractiveness. And in both studies, the major variable is that women are at different stages of their menstrual cycle. Now, in the first study, men are rating the attractiveness of women according to the smell of those women. Now, they're not smelling them directly. They're smelling clothing that women wore for a couple of days at different phases of their menstrual cycle. And what they find is that men will rate the odors of women as most attractive if those women wore those shirts, that clothing, in the pre-ovulatory phase of their cycle. Okay, so this is not to say that men do not find women attractive at other stages of their cycle. It is to say that men find women's odors particularly attractive if those odors were worn by women that are in the pre-ovulatory phase of their menstrual cycle. Okay, now there was also a study that was done where women at different stages of their menstrual cycle are rating the odors of men and a similar but mirror symmetric result was found such that women who are in the pre-ovulatory phase of their menstrual cycle will rate men's odors as more attractive than at other stages of their cycle. So the simple way to put this is that there seems to be something special about the pre-ovulatory phase of a woman's menstrual cycle that makes men rate them as more attractive during that time and women rate men as more attractive during that particular time as well. So this is a bidirectional effect. The way that the second study was done where women are rating men was not just to smell the odors of those men on t-shirts. They did that, but they correlated that with whether or not the shirts were worn by men that were particularly physically symmetrical. They actually had these men divided into groups. It was more of a continuum rather, rated according to body symmetry and face symmetry. And women preferred more symmetrical men when they were doing the preference test during the pre-ovulatory phase of their cycle. So again, the point is that that pre-ovulatory phase of the cycle seems to create a bi-directional mutual attractiveness. Now also extremely interesting is that this effect does really seem to have something to do with ovulation because in both studies, they had women that were taking oral contraception or not. And what they found was if a woman is taking oral contraception, it prevented that peak in perceived attractiveness by the men, meaning men no longer perceived a woman to be more attractive at a particular phase of their cycle. And also women taking oral contraception no longer preferred the odors of more symmetrical men during the pre-ovulatory phase of their cycle. Now I want to make sure that it's especially clear that it is not the case that oral contraception reduced the perception of a woman as attractive. That did not happen in these studies. It reduced the further increase in a male's perception of her as attractive. And if women took oral contraception, it prevented them from preferring more symmetrical men based on the odors of those men. Now I realize there are a lot of variables here. We've got odors, we've got symmetry, we've got menstrual cycle, pre-ovulatory, non-pre-ovulatory, and we have whether or not people are taking contraception or not. But the basic finding is that depending on where women are in their menstrual cycle influences both men's perception of them as attractive and their perception of men as attractive and oral contraception eliminates that effect. So I share with you those data to illustrate that we often think that somebody is attractive or not based on, I don't know how they look, their skin, their hair, et cetera, but it also illustrates that their odor is a powerful cue for some people more than others. Some of us tend to be more factory driven than others. Although if you watched the Huberman Lab podcast episode that I did with Professor David Buss from the University of Texas Austin, who's a luminary in the field of evolutionary psychology and has studied mate choice and mate selection bias over decades. He's really one of the founders of that field. He emphasized findings that odor for many people is a maker or a deal breaker. Meaning there are some people that even if somebody has all the characteristics that they're looking for in terms of kindness and attractiveness and values and other features that would and should be of very high priority in selecting a mate, that if someone does not like the way that person smells, their innate body odor, independent of colognes and perfumes and soaps, et cetera, that that's often a complete and total deal breaker. I'm sure there's some of you that can relate to that. And there's some of you perhaps for which that is not the case. And you can't even imagine that being such a powerful variable. And yet the data suggests that indeed it is a powerful variable for many people out there. Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is however, part of my desire and effort to bring zero cost to consumer information about science and science related tools to the general public. In keeping with that theme, I'd like to thank the sponsors of today's podcast. Our first sponsor is Athletic Greens. Athletic Greens is an all-in-one vitamin mineral probiotic drink. I've been taking Athletic Greens since 2012, so I'm delighted that they're sponsoring the podcast. The reason I started taking Athletic Greens and the reason I still take Athletic Greens once or twice a day is that it helps me cover all of my basic nutritional needs. It makes up for any deficiencies that I might have. In addition, it has probiotics, which are vital for microbiome health. I've done a couple of episodes now on the so-called gut microbiome and the ways in which the microbiome interacts with your immune system, with your brain to regulate mood, and essentially with every biological system relevant to health throughout your brain and body. With Athletic Greens, I get the vitamins I need, the minerals I need, and the probiotics to support my microbiome. 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