Read How Many Friends Does One Person Need? Online
Authors: Robin Dunbar
But investors given a single shot of oxytocin before they made their offer shared seventeen per cent more of their initial pot with the trustee than those sprayed with an inert chemical (a placebo). What makes it clear that this is about trust is the fact that when the experiment was re-run with the trustee’s decision being made at random by a computer (but with the same probability of defection – pocketing the money – as that shown by the trustees in the previous experiment), there was no difference between the oxytocin and placebo conditions in the investors’ willingness to share. In other words, it was not simply risk that the investors were betting on, but their understanding of human behaviour.
What makes this experiment particularly interesting is that oxytocin turns up in other important social contexts. It is released in copious quantities during and after sex, generating that sense of deep attachment that seems to permeate every corner of our bodies in the aftermath. Comparisons of monogamous and polygamous vole species suggests that the pairbonding that underpins monogamy in these species is also based on an especially high sensitivity to oxytocin. It also facilitates nest-building and pup retrieval in rats, and mother-offspring bonding in sheep.
This does not, of course, mean that our lives are regulated entirely by chemicals. Rather, the point is that these chemi-
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cals create a neural environment that is sensitive to certain kinds of cues when these are encountered. There are many other familiar examples. We have known for over half a century, for example, that the ‘flight/fight’ response is underpinned in much the same way by the hormone epinephrine (aka adrenaline): release of the hormone prepares the body for action, but which action (flight or fight) depends on how the individual perceives the circumstances.
By the same token, in the Zurich experiment, some of the investors who were given oxytocin were a great deal less generous than some of those in the control group. That probably reflects a combination of two supplemen-tary effects. One is likely to be individual differences in sensitivity to oxytocin’s effects: women, for example, are more sensitive to it than men, and there will be further variation within each sex. The other is likely to be investors’ sensitivities to the cues of honesty given off by the trustees once they have been primed by the hormone to pay attention to them.
I once took part in a management consultancy event in London that drew together a collection of around sixty individuals from all walks of business and government life. After the inevitable croissant-and-coffee breakfast, we were herded into a side room and asked to take a seat. The chairs had been set out in circles so that everyone faced the centre of the room. We sat for maybe five minutes or so in silence, with everyone becoming increasingly edgy and puzzled about what was going on.
Eventually, one by one – but always after several min-
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utes of intervening silence – the organisers stood up and said something to the effect of ‘I believe in... [something or other]’. This simply served to create even more edginess among the assembled throng, and nowhere more so than among a pair of rather out-of-place, primly besuited elderly gentlemen who were obviously on a skive from one of the government ministries just round the corner in Whitehall. They were clearly beginning to wonder what on earth they had let themselves in for when they could have been more usefully running the country...
Gradually, one or two of the audience began to join in with rather hesitant statements about their beliefs. Then someone stood up and said: ‘I believe that we are all wondering what on earth is going on.’ The assembled company broke into uproarious laughter. From that moment on, the atmosphere was completely different. The ice had been cracked. Suddenly, we were instantly transformed from a group of strangers into a band of brothers (well, and sisters too, of course).
Laughter, and especially communal laughter, seems to have an extraordinary capacity to create a sense of bondedness. It is not just a matter of releasing tension. You get the same effect if you go to a theatre to see a comedian. After an hour or so spent with tears streaming down your face, you emerge feeling on a high. You are relaxed, at peace with the world, full of bonhomie. Without a moment’s hesitation, you turn to a complete stranger and strike up an animated conversation. In those few minutes of passing conversation, you will probably have volunteered several snippets of personal details about yourself – something you would never have considered doing an hour or so before as you waited for the show to start.
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You will even become more generous towards strangers. When Mark van Vugt and his colleagues at the University of Kent asked subjects to share a sum of money they had been given with a partner, they were much more generous to an existing friend than to someone they had never met before. But if they watched a comedy video
and
laughed
together, they were as generous to strangers as to a friend. In some mysterious way, laughter turns strangers into friends.
In fact, it turns out to be anything but mysterious. Laughter – and I mean deep belly laughter, not the polite titters that tinkled among T. S. Eliot’s teacups – is an extremely effective releaser of endorphins, probably because the physical effort of laughter’s heaving chest is quite hard work for the muscles. We have demonstrated this using pain threshold as an assay of endorphin release. We tested subjects’ pain thresholds before and after watching either a boring tourist video or a comedy video in small groups. Since endorphins are part of the body’s pain-control system, pain thresholds should be much higher after laughing if laughter triggers the release of endorphins in the brain. And, so it was: those who laughed a lot while watching a comedy video had an elevated pain threshold afterwards, whereas those who watched a boring video showed no change.
I suspect that laughter is a very ancient trait. It is a behaviour we share with chimpanzees, though, as the psychologist Robert Provine has observed, the form is slightly different. In chimpanzees, it has a simple
hah-uh-hah-uh-hah
series of alternating exhalations and inhalations, whereas ours is a much more vigorous series of repeated exhalations without drawing breath:
ha-ha-ha-ha
. There
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are two other differences. We laugh socially, whereas chimpanzees typically laugh alone – they laugh in anticipation of, or during, a social situation, especially during play, but not together at the same time as we do. The other is that we use language (in the form of jokes) to trigger laughter. How boring is a conversation that isn’t peppered with one-liners?
This last was clearly a late development that appeared only after the evolution of language. But the first – the social nature of laughter – is almost certainly much more ancient, perhaps something that evolved as much as a million or so years ago in
Homo erectus
, the precursors of the first true humans. It was most likely a form of chorusing, a kind of communal singing without the words. Its function, I think, was to generate the same kind of surge of endorphins as that produced during grooming. My guess is that this kind of social laughter came on stream, built up out of more conventional chimpanzee-like laughing, to supplement grooming as a bonding mechanism once these early ancestors of ours hit the upper limits on the time they could afford for social grooming.
Still, laughter is not the only way we produce these endorphin surges.
You hear the distant strains of that old familiar song and there’s that moment of recognition, that tingling mixture of half-remembered emotions. For me, it might be the strains of a Buddy Holly song, or a snatch of one of Bach’s Brandenburg Concertos, or the skirl of massed bagpipes. But why is it that music moves us so?
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Perhaps surprisingly, music has remained until very recently one of the Cinderella areas of modern science, something too trivial for real scientists to dirty their hands with – evolutionary cheesecake, as the linguist Steven Pinker put it. And yet, as evolutionary biologists will never tire of pointing out, something that a species is prepared to devote so much time – and money! – to cannot be a trivial by-product. Whenever animals invest that much time and effort in something, it’s usually because it is of fundamental biological importance.
One suggestion – made originally by Darwin himself –is that music is a form of sexual advertising, rather in the way song functions in birds. Why else, you might ask, should sheer inventiveness of composition or musical skill play such a huge role in our appreciation of music? The fact that you can get your fingers or tongue around a complicated tune obviously demonstrates the quality of your genes to a prospective mate. It seems very plausible.
Sexual selection, as Darwin pointed out nearly 140 years ago in one of his other great books,
Sexual Selection and
the Descent of Man
, is an extraordinarily powerful force in evolution, well capable of picking up the most trivial traits and exaggerating them to the point where they actually become detrimental to those that possess them – at least in terms of daily survival. The peacock’s tail weighs him down when he flies, and so exposes him to a greatly increased risk of being caught by a predator. The payoff comes through greater success in the mating stakes. What the males are saying, in effect, is:
Watch me – I’m so good
I can handicap myself with all this and still beat the predators!
Males with flashy tails and more eyespots do so much better in the business of attracting lady peafowl. It
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is but one of many well studied examples from the animal world.
And there is a certain amount of evidence to support the proposal that music functions in this way for us, not least the self-evident sexual attractiveness of pop stars. The evolutionary psychologist Geoffrey Miller found that jazz musicians, pop musicians and classical composers are all most productive during the sexually active phase of their lives. And it is no accident, surely, that Vivaldi’s efforts were exercised so strenuously on behalf of the young ladies of Venice’s Ospedale della Pietà orphanage – many of whom found rich husbands thanks to the skills exhibited in the concerts they performed under his direction.
To test Miller’s hypothesis more precisely, one of my students, Kostas Kaskatis, looked at the productivity of nineteenth-century classical European composers – everyone from Beethoven to Mahler – and 1960s-vintage rock stars. He found that the number of new works they composed dropped off dramatically after they had married, but then rose again as soon as they had separated or divorced and were once more on the prowl for a new mate. And once they had found someone new... yes, it dropped off again.
Well, it may be so. But another possibility is that music had its origins in social bonding. There is something raw and primitive about music’s ability to stir the emotions. Every parade-ground martinet knows that songs are the best way to create a sense of camaraderie in a group of raw recruits.
Recent brain-scan studies indicate that music seems to stimulate deeply primitive centres at the front end of the
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right hemisphere of the brain. In rather crude terms, the left half of your brain is more active in conscious processes – hence the fact that it is particularly strongly implicated in language – whereas your right half is more active in those unconscious, more primitively emotional aspects of behaviour.
Another recent finding is that music triggers the release of endorphins. Because endorphins play a powerful role in creating that sense of wellbeing and contentedness that is so important in the process of social bonding, it is not hard to see how singing and dancing might have functioned as a device to generate that sense of belonging, or groupishness, that is so fundamental to the coherence of small human communities the world over. There is nothing like a ceilidh (the word means literally ‘a visiting’ in Gaelic) to bring people together.
This doesn’t mean to say that Darwin was wrong, of course. There is every reason why sexual selection should have exploited for its own ulterior purposes the skills and emotions involved in producing music that had evolved for some entirely different purpose. Evolution is very good at doing that, and there are many examples of just this in the animal world. But at root, music’s real origins and function probably lie in bonding social groups. And herein probably lay the origins of language itself.
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Why is it that we are so fascinated by what other folks get up to? Why should we find tittle-tattle about the pri-vate lives of minor celebrities, royalty, politicians and even each other of such overwhelming interest that it can drive the starving children of Darfur or the war-ravaged cities of Somalia and Iraq off the front pages of even the most sedate of newspapers? The reason is very simple: gossip makes the world go round.
So how much time did you waste yesterday wittering away nineteen to the dozen? I’ll wager it was getting on for a quarter of your entire day. And what came of it all? Probably not a lot, you might say. But it wasn’t totally frivolous. It’s an odd thing, this language business: we find it intensely embarrassing to remain silent in company. We cast around desperately for something to say, however meaningless. Um... do you come here often?
So why do we do it?
One answer is that language is just a form of grooming. For monkeys and apes, grooming is less a matter of
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hygiene and more an expression of commitment. Its sense is more that of: ‘I’d rather be here grooming with you than over there with Jennifer.’ We still do a great deal of mutual mauling of this kind, of course. It’s an essential feature of all intimate relationships. Parents and offspring, lovers, friends – all are willing to spend hours stroking, touching, leafing through hair. Physical contact, in short, is an essential part of the rhythm of social life.