Book review: How Many Friends Does One Person Need?

Published on Friday 26 February 2010 18:50

HOW MANY FRIENDS DOES ONE PERSON NEED? By ROBIN DUNBAR Faber, 302pp, £14.99

IF YOU want the definitive answer as to why Barack Obama won the 2008 presidential election – why commentators keep asking, more than a year on, is another question – look at his face. No, not the colour: the symmetry.

According to Robin Dunbar, professor of evolutionary anthropology at Oxford, we are programmed to favour symmetrical faces over asymmetrical ones, especially when it comes to matters of trust. And John McCain's face isn't as symmetrical as Obama's. (He's also not as tall.) At election time, in an age of image-based media, we don't so much listen to what our politicians have to say as watch how they say it – even when we think we're listening.

You have suspected as much already, of course. But Dunbar's mission is to reveal the science behind our reactions. He points to an experiment carried out at Liverpool University, where researchers made up composite photos from the facial features of the winners and losers in each of the last two British and US elections and asked a sample group which one they'd go for. More than half – 60 per cent – picked the face composed from the mirrored images of the various winners' features, suggesting that when it comes to voting not only do we like facial symmetry, we go for it even when we don't recognise the face. Why? Symmetry is a sign of "top-quality genes" which we're hard-wired to spot.

This book is packed with such snippets as Dunbar explains why we can't cope with more than 150 people in our lives, whatever Facebook may say; why women gossip and men brag; why laughter is good for you, and morning sickness is good for your baby. It's all done in a colloquial style, making the case for science to a lay audience – and science, badly bruised of late, needs its ambassadors. Sometimes, as he moves from point to point, you wish he'd stay put for a moment; and his chattiness, which must work brilliantly in a lecture hall, can grate in print. But just when you think that the "evolutionary quirks" of his subtitle are just that – mildly amusing footnotes to human behaviour – he hits you with a killer statistic, sobering moment from history or troubling ethical dilemma.

So, in his chapter "Who'd Mess with Evolution?" he ends up, via a thoughtful critique of the in utero sexing of babies, with China – and the law of unintended consequences. When the country brought in its one-child policy in the 1970s nobody thought of the deep-seated preference in rural areas for boys over girls. Today, so many girls are aborted that the population is tipping out of balance – bad news for the mating game; worse news for society. Expect a burgeoning gang culture and soaring rape statistics, Dunbar warns, as China is overrun by "40 million sexually disgruntled young men". No-one needs any friends like that.