I was recently invited to give a couple of talks at the University of Michigan’s “Summer Institute in Cultural Neuroscience.” To be honest, I wasn’t sure why the conference organizers (Shinobu Kitayama and Carolyn Yoon) had chosen me to give one of the “Lectures on culture, brain, or both ... delivered by world-renowned scholars.” The truth is I don’t know a lot about the brain, and in a room with someone like Shinobu Kitayama, I hardly qualify as a world-renowned scholar on culture. But the conference program goes on to explain how: “In recent years, it has become increasingly clear that although the brain is biologically based, it is also socially shaped and conditioned as it functions in dynamically changing cultural worlds. Cultural neuroscience is an emerging research discipline that investigates cultural variation in psychological, neural and genomic processes as a means of understanding the relationship among these processes.” I was fascinated with the intriguing ideas and data that Kitayama and Uskul presented in a recent Annual Review paper titled “Culture, mind, and the brain.” So given that I’ve published some papers on cross-cultural similarities in behavior from an evolutionary perspective, and on dynamical emergence of social norms from evolved decision-rules, I figured I could come up with enough interesting findings to fill three hours of lectures. Perhaps most importantly, I didn’t want to pass up a chance to get away from the scorching Phoenix summer and enjoy a corned beef sandwich at the world famous Zingerman’s deli.
Michigan's weather turned out to be hot (and humid, which really does make a difference), but the sandwich was fantastic, and more importantly, I scored a wonderful learning experience. Giving a new talk on a new topic of course forces you to learn something, if only a new perspective on your own work. But by the time I got on the plane to return to Phoenix, I had a completely new set of ideas to digest about the relationships between genes and everyday experience.
I’ve long been aware that genes do not rigidly determine behavior. I’d always assumed the lack of rigidity arises mainly from the fact that genes build flexible neural structures. And I was aware that some genes don’t turn on until particular developmental milestones are met (such as those involved in the development of secondary sex characteristics when a person accumulates sufficient caloric bulk to undergo puberty). But I had not before appreciated the extent to which genes continue to be active throughout our lives, turning on and off as we interact with the events and people we encounter on a daily basis.
I read two papers that really drove home this point, and that also left me in awe about how rapidly researchers are uncovering the details of how genes dynamically interact with social experience. The first paper was one I assigned to show good faith to the goals of the conference. It was a concise review on “Genes and Social Behavior” published in Science by Gene Robinson, Russell Fernald, and David Clayton. Fernald and his colleagues have done some absolutely fascinating research tracking the hormonal and genetic changes that happen in male cichlid fish when a dominant male is removed from the group. As soon as the dominant male is removed, a male who was previously subordinate starts to behave in a more dominant fashion, and begins building new neural structures in his brain, as well as becoming more colorful. These effects are linked to the activation of a specific transcription factor-encoding gene (egr1) that has been found to be involved in social behaviors across a wide range of species (including song recognition in zebra finches and mothering in rats). The paper lays out an interesting model of interactions between genes, brains, and behavior on three time levels (physiological, developmental, and evolutionary). Incidentally, in some fish species, all the fish begin life as females, and when a dominant male dies, the largest female in his harem immediately grows larger and more colorful, and changes into a male. For clownfish (like Nemo) it works in reverse, they all begin as males and may later change to females if a dominant female dies (a detail Disney skipped over in the children’s movie).
That paper turned out to be closely linked to the talks given by the speaker who followed me – Steve Cole of UCLA. He gave a fascinating pair of lectures on the emerging field of social genomics, describing how human genes are turned on and off by stressful experiences (such as loneliness), and how those experiences can change the molecular structure of our cells, and hence the structure of our brains and bodies, in ways that unfold over hours, days, months, and lifetimes, and that are sometimes reversible, but sometimes not.
What’s particularly exciting about all that is this: It suggests an intricate connection between a) events that happened thousands and even millions of years ago (when particular genes were selected because of their consequences for adaptive behaviors), b) our developmental experiences, and even c) what’s going to happen to us later today, tomorrow, and next week.
Doug Kenrick is the author of the recent book Sex, Murder, and the Meaning of Life: A psychologist investigates how evolution, cognition, and complexity are revolutionizing our view of human nature.
Cole, S.W. (2009). Social regulation of human gene expression. Current Directions in Psychological Science, 18, 132-137.
Kitayama, S., & Uskul, A.K. (2011). Culture, mind, and the brain: Current evidence and future directions. Annual Review of Psychology, 62, 419–449
Robinson, G.E., Fernald, R.D., & Clayton, D.F. (2008), Genes and social behavior. Science, 322, 896-900.