“What is the sexiest part of the human body?” screamed the headline of a full-page movie advertisement in the Sunday New York Times. The title of the movie escapes me now, but as an impressionable young man of 15 I eagerly read down the list of possible answers: Is it the Eyes? Lips? Legs? No, No, and No! The nape of the neck? Buttocks? Breasts? Genitals? Incorrect! My confusion grew, as did my doubts about the credibility of my 9th grade human biology teacher. How could it not be the genitals? What was Mr. Doty holding back from us? The advertisement delivered the punch line: The Mind is the Sexiest Part of the Human Body!
Rarely had a newspaper ad held so much promise for me, and so much disappointment. To be fair, I welcomed the news about the nape of the neck, and I made a mental note to think about how this knowledge might give me some competitive advantage with the girls in my class. But the mind? I could barely get close enough to a nape to make it matter, much less figure out a way to stimulate an organ I could not even see, much less understand. Fast-forward 30 years or so, and we learn how little it takes to accomplish this crucial human task.
Imagine participating in the following study, which was conducted by psychologist James Coan and colleagues. As you lay flat on your back in an MRI scanner, you see on a video monitor in front of you either a red X or a blue O against a black background. The letters are presented 24 times in total, in a random order, for 1 second. You have been told that when you see the X there is a 20% chance that you will receive a mild shock delivered in the next few seconds via an electrode attached to your ankle. When you see the O, there is a 0% chance that you will receive a shock in that period. X is occasionally a threat, O is always safe. Because the large magnet encircling your head detects minute changes in metabolic activity in those areas of your brain that were activated in the interval immediately following the X or the O, this procedure permits identification of specific brain regions that are uniquely activated when you anticipate the shock as compared with when you know that no shock is forthcoming. Now imagine that you undergo this procedure under three separate conditions, also randomly ordered, in which you either hold your intimate partner’s hand, the hand of a stranger who is the same sex as your partner, or no hand at all.
Analysis of the brain images that were collected after you see the dreaded X or the safe O (but before any shock actually occurs) indicates that holding your partner’s hand reduces activation in those brain regions that govern emotional and behavioral responding to threat responses, to a greater degree than holding either no hand or the hand of a stranger. By holding our partner’s hand, it seems, we are able to influence his or her emotional reaction to the world they are experiencing, in perhaps the most basic and direct way possible. And the same study shows that some people benefit more than others: the degree to which brain activation is reduced in the face of threat depends on how happy we are in our relationship; the happier the relationship, the greater is the apparent benefit that comes from holding our partner’s hand.
The surprising implication of all this is that nature has endowed each of us with a nervous system that is exquisitely tuned into and altered by the presence of an intimate partner. Engaged with only the smallest of gestures, the human capacity for intimacy — like the capacity for language, or reasoning, or social perception — enables two people to regulate one another’s emotions and to adapt to threats they perceive in the world around them. Understanding intimate relationships, this basic feature of who we are and how we survive, is therefore essential to understanding the emotional lives we lead.
Coan, J.A., Schaefer, H.S., & Davidson, R.J. (2006). Lending a hand: Social regulation of the neural response to threat. Psychological Science, 17, 1032-1039.