2014 : WHAT SCIENTIFIC IDEA IS READY FOR RETIREMENT?

Back in the 1970s, the Nobel-prize winning ethologist Niko Tinbergen liked to trace out a graph; one line on it rose slowly over time, showing the rate of our genetic evolution, a second curved steeply upwards showing the rate at which he saw our culture changing. He would speculate whether the gap between the environment we had evolved in and the one in which we now found ourselves might be the root of a number of ills. Since then, such ideas have spread, in part because of the rise of evolutionary psychology.

In its strong form, evolutionary psychology holds that the human mind is like a Swiss Army knife, made up of many innate special-purpose modules, each shaped by natural selection to solve problems encountered during Homo's long pre-civilization life. With ninety-nine per cent of our evolutionary past spent as hunter-gatherers, it seems reasonable that modules which were adaptive in past circumstances still dominate our thinking. Thus women will naturally find athletic men—the kind who would be good hunters—to be especially attractive; if we had instead spent the Pleistocene delving the earth like Tolkien's dwarves then short, barrel-chested men would now appeal. In the popular imagination, evolutionary psychology has cast us as Stone Age thinkers in modern times, our brains not wired to cope with offices, schools, courts, writing and new technology.

It's a beguiling idea, suggesting that somewhere out there is a more natural world in which we would feel truly at home. But there is little evidence for the idea or that the whole of our psychology is shaped so rigidly by our Pleistocene past. It is time for it to retire and for us to think more widely.

New ideas and data from the cognitive sciences, comparative animal behavior and evolutionary developmental biology suggest we should not compartmentalize culture and human nature so sharply. Rather, culture and social processes shape brains that in turn shape culture and are transmitted onwards.

Reading provides a nice example. The ability to pass on and accumulate information has transformed our world, but written languages appeared only in the past 5,000 years ago, not long enough for us to have evolved an innate "reading module". Still, if you look inside the brain of a literate person, it will light up quite differently from that of an illiterate one, not just when reading but also when listening to spoken words. During the social process of being taught to read, infant brains are remodeled and new pathways created. If we didn't know this cognitive capacity was produced by social learning we'd likely think of it as a genetically-inherited system. But it is not: our brain and minds can be transformed through the acquisition of cognitive tools which we are then able to pass on again and again.

Of course, it is reasonable to assume that those cognitive tools have to fit nicely with how our brain works, just as a physical tool has to fit well in our hands. But as a species we seem to possess remarkable powers to keep building and rebuilding our cognitive tool kit through interaction with others. It is surprising how similar humans and chimpanzees are when they are infants—in skills like numeracy and behavior reading—and yet so different when they are adult. Beyond a certain age, humans are propelled along a different developmental trajectory, in part because they are immensely socially motivated to interact with others, which chimpanzees are not. Evolutionary developmental psychology has thus become a hot research topic, as it will hold the key to the way social processes unfold minds.

Culture and the social world shape our brains and give us new cognitive capacities that we can pass along, evolving culture as we go. We shouldn't think of the cultural world as separate and estranged from our biological selves, but something that shapes us, and is in turn transmitted by us. Such a view suggests that rather than being alienated hunter-gatherers lost in the modern world, we are in flux and still may have only a narrow conception of what humans could be.