I'll Scratch Your Back . . .

Tuesday's New York Times is always good for one or two evolutionary psychology-type articles in the Science section. Today's looks at Michael Tomasello's research into humans' innate desire to help others:

When infants 18 months old see an unrelated adult whose hands are full and who needs assistance opening a door or picking up a dropped clothespin, they will immediately help, Michael Tomasello writes in “Why We Cooperate,” a book published in October. Dr. Tomasello, a developmental psychologist, is co-director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

The helping behavior seems to be innate because it appears so early and before many parents start teaching children the rules of polite behavior.

“It’s probably safe to assume that they haven’t been explicitly and directly taught to do this,” said Elizabeth Spelke, a developmental psychologist at Harvard. “On the other hand, they’ve had lots of opportunities to experience acts of helping by others. I think the jury is out on the innateness question.”

But Dr. Tomasello finds the helping is not enhanced by rewards, suggesting that it is not influenced by training. It seems to occur across cultures that have different timetables for teaching social rules. And helping behavior can even be seen in infant chimpanzees under the right experimental conditions. For all these reasons, Dr. Tomasello concludes that helping is a natural inclination, not something imposed by parents or culture.

This bit in particular I thought interesting:

An interesting bodily reflection of humans’ shared intentionality is the sclera, or whites, of the eyes. All 200 or so species of primates have dark eyes and a barely visible sclera. All, that is, except humans, whose sclera is three times as large, a feature that makes it much easier to follow the direction of someone else’s gaze. Chimps will follow a person’s gaze, but by looking at his head, even if his eyes are closed. Babies follow a person’s eyes, even if the experimenter keeps his head still.

Advertising what one is looking at could be a risk. Dr. Tomasello argues that the behavior evolved “in cooperative social groups in which monitoring one another’s focus was to everyone’s benefit in completing joint tasks.”

This could have happened at some point early in human evolution, when in order to survive, people were forced to cooperate in hunting game or gathering fruit. The path to obligatory cooperation — one that other primates did not take — led to social rules and their enforcement, to human altruism and to language.

But then so was this:

The division of labor between men and women — men gather 68 percent of the calories in foraging societies — requires cooperation between the sexes. Young people in these societies consume more than they produce until age 20, which in turn requires cooperation between the generations. This long period of dependency was needed to develop the special skills required for the hunter gatherer way of life.

The structure of early human societies, including their “high levels of cooperation between kin and nonkin,” was thus an adaptation to the “specialized foraging niche” of food resources that were too difficult for other primates to capture, Dr. Kaplan and colleagues wrote recently in The Philosophical Transactions of the Royal Society. We evolved to be nice to each other, in other words, because there was no alternative.

Feck it, read the whole thing.