The Science of Giving
(December 23rd 2008) Christmas is the occasion for giving par excellence, but what does 'giving' actually imply? Scientists, social scientists, economists and philosophers continue to grapple with the human qualities of altruism, sharing and selfless giving. Jeremy Garwood reports on searches for an evolutionary rationale to such behaviour.
Christmas is the occasion for giving par excellence, but what does 'giving' actually imply? Scientists, social scientists, economists and philosophers continue to grapple with the human qualities of altruism, sharing and selfless giving. Jeremy Garwood reports on searches for an evolutionary rationale to such behaviour.
Although most of the world's religions exhort the faithful to acts of charity, the advent of evolutionary theory and natural selection in the nineteenth century led to interpretations of altruistic behaviour as somehow weak and against nature. Behind phrases like 'the survival of the fittest', Social Darwinism could not understand why anyone would give up their time, effort and resources without the certainty of making gains or acquiring future advantage for themselves or their offspring. To them, altruistic behaviour was hypocrisy, while the selfless giving of gifts was simply senseless.
In the twentieth century, economists were obsessed with the all-pervading actions of Homo economicus, their 'perfect' economic man (or woman), a purely rational being who only acted in his own economic interests - Homo economicus always uses his available resources to minimise loss and maximise his profit. Homo economicus would not perform a charitable act, make a donation, or give a present without having a perfectly rational explanation of how he would gain by this uncharacteristic behaviour. If Homo economicus gives you a Christmas present, you can be sure he's calculated that you'll be giving him a bigger, better one in return!
Molecular biology has now waded into the debate. A couple of years ago, a Canadian researcher, Aurora Nedelcu, announced that she had found the real reason for altruistic behaviour - it's genetic! In fact, it's so fundamentally genetic that she claimed to have found the 'altruism gene' in green alga, Volvox carteri, an organism so simple that it lies at the evolutionary interface between single-cellular and multicellular life. Volvox forms a pretty ball of around 2000 cells in which all but 16 of the cells permanently renounce reproducing themselves to take on other jobs, such as moving the group around by swimming. A similar division occurs in most multi-cellular creatures: their cells are either "germ" cells-reproducers such as sperm and eggs-or "somatic" cells, all the others, which leave no heirs after the individual dies. This can be seen as a profound form of altruism. By not reproducing, somatic cells commit evolutionary suicide to benefit the group. The 'altruism gene', regA, favours such reproductive altruism by limiting cell growth - cells need to grow a bit bigger to reproduce. Unable to reproduce, it is argued the regA-expressing cells 'altruistically' shift their behaviour towards group cooperation.
Other researchers dispute that such behaviour in simpler organisms really equates to human altruism at all. They argue that human societies exhibit patterns of cooperation and a detailed division of labor that are unique in the animal world. Humans frequently cooperate with genetically unrelated individuals, even in large groups and when there are no prospects for future interactions. However, this constitutes an evolutionary puzzle because kin selection, reciprocal altruism, and reputation-based models cannot explain these patterns of cooperation. Just why do human societies behave like they do?
Because we're emotional? Cognitive and neurobehavioural research now suggests that not only are we imperfect copies of Homo economicus, in fact we don't behave anything like him! Unlike the cool, rational calculations of Homo economicus, real people are emotional - they possess highly evolved neuronal circuitry that determines their social behaviour, and this isn't necessarily rational. It means you can give the biggest and best presents without feeling guilty that you're only going to get socks and useless gadgets in return.
Indeed, the field of Neuroeconomics has now given Homo economicus a brain (about time too!). A recent study demonstrated the importance of the interplay of emotions and cognition in economic decision making. Participants who responded to fair and unfair offers in a bargaining game were scanned using functional magnetic resonance imaging (fMRI). Less fair offers activated the bilateral insula, part of the brain implicated in negative emotional states, such as disgust, pain, hunger, and thirst. Unsurprisingly, the subjects with the strongest insula activation to unfair offers were also more likely to reject these offers. Insula activation is also social since unfair offers from a human partner caused stronger activation than those received from a computer. Unfair offers also activated the dorsolateral prefrontal cortex, a region often associated with goal maintenance and executive control, and the anterior cingulate cortex, implicated in detection of cognitive conflict.
This and similar neuroeconomic studies that scan subjects' brains while they are making decisions in interactive economic experiments support the hypothesis that neural representations of emotional states guide human decision-making and suggest that subjects derive specific rewards from mutual cooperation and the punishment of 'norm violators'. Nevertheless, such fMRI studies have yet to be performed on the fair exchange of Christmas presents!
Swiss researchers, Ernst Fehr and Bettina Rockenbach, claim to have revealed the neural basis of human cooperation. Asking why we cooperate at all and what the mechanisms are that enable and sustain human cooperation, even in social situations with considerable numbers of selfish indivduals. According to them, human social and economic cooperation can only function because we have people who are willing to reward fair behaviour and to punish unfair behaviour, even though this may often be quite costly and provide no material benefit to the people in question, the so-called 'strong reciprocators'. However, since 'strong reciprocity' is costly for the individual reciprocator, the question still arises as to how such behaviour could have evolved, even if strong reciprocators in the human population may have contributed to the 'evolutionarily stability' of human society.
Leipzig researchers, Felix Warneken and Michael Tomasello, have looked at altruistic behaviour in young children and chimpanzees. They have found that human children as young as 18 months old will quite readily help others to achieve their goals in a variety of different situations, e.g. picking up out-of-reach objects, or opening cupboard doors. They also showed that young chimpanzees displayed similar skills and motivations, although to a lesser degree. As with the human infants, the chimps did so without receiving any benefit (reward or praise) for helping. Warneken and Tomasello say such behaviour requires both an understanding of others' goals and an altruistic motivation to help. Furthermore, their results with helpful chimpanzees indicate that chimps share crucial aspects of altruism with humans, suggesting deeper evolutionary roots to human altruism than previously suggested in their domain - presumably not as far back as Volvox?
Meanwhile, Fehr and Rockenbach have studied food-sharing among hundreds of Swiss schoolchildren aged 7 to 8. They found that not only will these older children provide food for others when it is of no cost to themselves, but that they will also seek an equal distribution of food, even in situations where they could potentially take a larger share for themselves, or where they might give a larger share to some individuals. Apparently the children really do care about what the 'other' is getting, and they want this to be the same as for themselves. However, it was noted that this is especially true when the 'other' is from their own group, i.e. one of their classmates, rather than from a different group - an observation that brings us nicely back to evolutionary models postulating roles for such altruistic group cooperation in maintaining gene pools of larger, inter-related groups.
In their latest research, "Extrinsic rewards undermine altruistic tendencies in 20-month-olds" (Dev Psychol., Nov. 2008), Warneken and Tomasello report further studies on the helpful behaviour of their young children. Unfortunately, this time, they looked at the effect of materially rewarding the children for their previously altruistic acts. The bad news for altruism is that once the children had been rewarded they were much less likely to continue to be helpful! Parents beware!
"This so-called 'overjustification effect' suggests that even the earliest helping behaviors of young children are intrinsically motivated and that socialization practices involving extrinsic rewards can undermine this tendency."
Perhaps that might explain some of the reactions following the exchange of Christmas presents!
