A man hangs up brightly colored pieces of paper on a line with clothespins one by one, nattering to but not interacting with a toddler. As he gets to the last piece, he drops the clothespin and leans over the line to try to reach it, but can't, quite. The toddler, seeing him struggling to reach the clothespin, leaves Mom's side without any prompting, toddles over, picks up the clothespin and hands it to the man. The man is Alan Alda in a clip from his upcoming PBS show, The Human Spark, and the toddler is part of an experiment in altruism and cooperation at the Max Planck Institute for Evolutionary Anthropology run by Michael Tomasello. As one, the audience watching this clip coos "awwwwwww" when the toddler helps Alda out. We're suckers for a baby, even those of us who aren't mothers. How can we help it? We're being bombarded with cute stimuli (like what you experience every time you go to Cute Overload). And this reaction, according to anthropologist Sarah Hrdy, is one of the things that helps distinguish us from the other primates, even the ones who share most of our DNA. It's what makes us altruistic—and human.
Or at least that was the upshot of the extended conversation between evolutionary biologists E. O.Wilson and Dominic Johnson, anthropologists Sarah Hrdy and Rob Boyd, geophysicist (yes, geophysicist, and I'll tell you why in a minute) Xavier LePichon and Alan Alda, actor and quintessential Emo Guy on the second night of The World Science Festival's "What It Means to be Human: The Enigma of Altruism." What makes altruism, the act of doing a good deed without expectation of reciprocity, an enigma? As Alda pointed out in his introduction, it was one of the factors that darn near "annihilated" the theory of evolution before it even got off the ground. Specifically, it was E.O. Wilson's favorite critters that stumped Darwin. Ants, like bees, have a worker caste who don't reproduce and whose genes do not enter the gene pool. Darwin got around this by stating that the queen is actually the unit of natural selection, not the rest of the colony. This is like breeding a garden plant for its tasty seed carrier (vegetable or fruit). You're breeding the plant, not the the fruit.
This led to one of the competing theories of altruism, kin selection. As my hero, Robert Heinlein once stated, your genes belong to your species, not to you as an individual. So theoretically, helping out your relatives perpetuates part of your genetic material. The closer the relative, the more of your DNA you're helping perpetuate. You'll help out or sacrifice yourself for your relatives because they carry part of your DNA. Its not true altruism; the underlying motive is indirect but very strong: the perpetuation of your genes.
Competing with this idea was the theory of group selection, which is more like Darwin's. It's not just your direct blood relatives you'll help out, but people in your social group who carry only part of your DNA, even if it's more diluted. This makes sense in the context of larger social units like tribes and even nations.
But humans often practice what's called indirect reciprocity: giving back not to the person to whom you owe something, but to a complete stranger or society in general. Very often, this not only benefits the giver not at all, but actually harms them. Think soldiers who volunteer for active combat in situations where their families are not directly threatened. Better yet, think anonymous bone marrow donor, or the unrelated friend who will donated a kidney. Sure, you feel good about it, but is that enough to motivate a complete stranger or even a close friend to suffer through painful surgical procedures?
Why yes, apparently it is. And this too is an evolutionary development,one not shared by most animals. It appears only in social insects (which Wilson gleefully pointed out are 2/3 of the biomass; "Insects own the world!') and, not in our closest primate relatives, but in mammals like marmosets, that practice cooperative child rearing and that Hrdy described as spontaneously offering food and aid to non-relatives, just like the toddlers in that clip. In all that biomass, there are only about 20 examples of highly evolved social structures that emphasize cooperation, let alone altruism.
Altruism is only a facet of the complex cooperative societies that humans develop, but it seems unique to us. Chimpanzees and other primates cooperate, but the difference between our behavior and that of ants or bees or marmosets or even other primates is that "awwwww" factor: our ability to empathize. Xavier LePichon, a geophysicist best known for his model of plate tectonics, has also done extensive research into compassionate behavior among humans. He's lived for many years with the mentally handicapped and gave a striking example of the type of behavior involved in human altruism that occurred among Neanderthals. In a cave in Kurdistan, archaeologists discovered the interred remains of a 40-50 year old Neanderthal man whose skeleton showed signs of both ddeformity and healed severe trauma: probable blindness in one eye from a shattered orbit, a withered arm which had lost the lower portion and hand, and foot and leg deformities that would have crippled him. He would probably have required a great deal of help from his community and yet the fact that his injuries were old and had healed probably indicates that he had it, when he could so easily have been abandoned. LePichon adds that he sees this kind of compassion in the students who come to "help" in the handicapped community he has been living in. That desire to help eventually gives way to empathy and love.
Of course, all this begs the question of why altruism developed anywhere. And here Hrdy and Wilson have some other interesting things to say. Wilson points out that the development of social insect societies is tied to the building of elaborate nests provisioned for care of the young. A change in only one gene turns off the desire of young to leave when they're grown and the impulse of the mother to abandon the original nest and build a new one. This was such a successful adaptation that, voila! termites, bees, and ants developed cooperative societies. Group selection behavior overcomes individual selfishness. In humans, Hrdy explains that the equivalent of this was the existence of big, bipedal mammals living in savannah conditions where a camp could be provisioned both by hunters and supplemented by gathered food. The rapid development of the forebrain in this case, almost twice as fast as any other part of the body, illustrates the gene-culture (or nature-nurture, if you will) feedback loop in which learning to read intentions and emotional development gave such groups advantages over those without them. In other words, developing a nest where some stay behind to cooperatively care for the young and gather local food and some go out to find more food and bring it back, gave some groups enough stability to develop language and the ability to read emotional cues, as well as the monitoring of the self and others to form a successful social dynamic that benefitted the whole group.
Language played a part in this but so did things like . . . jewelry. That class ring you've got hanging around in your drawer? The equivalent of that was something like a handmade soapstone bead that one member of this group made for herself and others. That marked them as members of the same group and worthy of protection and cooperation. Extrapolate from this bead to sorority pins, class rings, uniforms, and national flags and you'll get the idea.
But what, exactly, caused this sudden boom in cooperation to begin with? Here's where the conflicting ideas got really interesting to me. One of the factors that both Johnson and Boyd talked about is the cooperation of conflict. As Alda pointed out, we seem to be really good at cooperating to kill other people. Boyd sees this as one of the factors that escalated the scale of cooperation. As Boyd points out, there has always been aggression. When it moved from an individual level to a group level, those who could cooperate better may have had an evolutionary advantage.
Johnson especially pointed out what he called the Machiavellian nature of cooperation, that ability to manipulate others for our own ends. And of course, this is what societies as a whole do: they teach (indoctrinate) and monitor their members to ensure cooperation. As the Japanese say, the nail that sticks up gets hammered down. But not all societies have this level of conformity in cooperation and there, both aggression and religion are seen to play a role. Gossip, status and reputation management still have a role in less conformist societies as a way of keeping everyone on the same level.
But cooperation is not altruism, and altruism is a distinctly human trait, one that seems almost completely absent in other species, where cooperation is while not common, not unheard of either.
Hrdy, on the other hand, believes the development of cooperative childrearing was one of the major factors that led to social cooperation and altruism. As she points out, nurturing is just as prevalent in humans as aggression is. When men are more involved with childcare, their prolactin levels increase and their testosterone decreased, a fact that elicited some nervous laughter from the men in the audience and applause from the women. Hrdy's latest book, Mothers and Others: The Evolutionary Origins of Mutual Understanding "argues that unlike other apes, Homo sapiens could never have evolved if human mothers had been required to raise their offspring on their own" (John Odling-Smee in Nature). This completely changes the focus of not just evolutionary theory, but sociobiology, which is infamous for being used to justify male bad behavior like rape. If the driving force behind human evolution was caregiving and not aggression, that gives us an entirely different view of ourselves. I was immediately put in mind of Sherri Tepper's book, The Gate to Women's Country in which aggression is being slowly bred out a post-apocalyptic society. Hrdy's theory is as much about what's valued in a society as what made us the way we are—and whose viewpoint is more valuable. Aggression has indeed always been around, but its end result is more often destructive than cooperative nurturing is. So if it's our hardwiring to care for each other rather than to destroy that's really the difference between us and other creatures, where does aggression fit in? Perhaps it's slowly becoming a maladaptive trait.
In another clip from Alda's upcoming series, one anthropologist remarks that if New York City were filled with 10 million chimpanzees instead of humans, it would be a very different place. I'm grateful for that every time I get on the subway at rush hour.