A Conversation with Michael Platt.

Dr. Platt: It is a bold claim to say something is a homology, because that really means that it basically arises from the same biological substrate. It emerges developmentally in the same way, it serves a similar function, and in terms of behavior it looks the same, as well. My statement isn’t just based on our work, but of course many other people as well. We have been fascinated by nonhuman primates and macaques in particular because their behavior, especially their social behavior, bears somany hallmarks of our own. They, like people, live in large groups that havemales and females. They live a long time. They identify each other on sight, they know who is related to whom, they know who outranks whom. They understand third-party relationships. One of the things that I think is really important about these animals is that they engage in behaviors that are very similar to ours to form cooperative alliances that they use to advance their own causes. Some monkeys invest a lot of time and energy in developing friendships. Friends come to their aid. We know that—just like for people—the deeper, more numerous connections that a monkey has, the better he or she is going to do. They’re going to live longer, they’ll be healthier, less stressed out, have more offspring. With people, it’s more or less the same thing: live longer, happier, healthier life, evenmakemore money. The functions and the behaviors themselves are very similar and what we, and others, have begun to discover is that essentially the system in the brain—the circuitry that allows us to manage our connections with others—is exactly the same as what the monkey has in his or her brain. It’s the same bits of stuff wired up in very similar ways. We have identified by comparison between monkeys and people that when we engage in various kinds of social interactions like this, the way that our brains process that information looks virtually identical to what we see in monkeys using complementary techniques.