Dominic Johnson recently took part in the “What it Means to Be Human” panel at the World Science Festival in New York (June 2009). The panel, chaired by Alan Alda of MASH fame, featured Ed Wilson, Sarah Blaffer Hrdy, Rob Boyd and Xavier Le Pinchon. Alda hosted the PBS documentary “Scientific American Frontiers” for over ten years, and will host a new three-part series in 2009 on human evolution called “The Human Spark“. We discussed the origins, development and current problems in understanding human altruism – a key focus of evolutionary theories of religion but a phenomenon that remains controversial in nearly all disciplines.
Definitions are crucial, so first off let’s clarify that altruism is A helping B at a cost to A (and benefit to B) that will never be returned. Darwin was greatly troubled by apparent altruism in nature – how could bees, for example, evolve to have stings that are fatal for the bee itself? There appears to be no room in the survival of the fittest logic for that. Darwin worried that the problem of altruism might destroy his entire theory of evolution by natural selection. The puzzle of altruism only really began to be solved a century after Darwin. W.D. Hamilton developed the theory of kin-selection (A helps related individuals because they share the same genes), Robert Trivers proposed reciprocal altruism (A helps B if B helps A tomorrow), and later on this was extended to indirect reciprocity (A helps B and, by gaining a reputation for positive interactions, others such as C, D, and E help A in turn). These theories pretty much solved the puzzle of “altruism” in non-human animals (it was only apparentaltruism – really it was just cooperation, meaning mutual benefits to both parties).
However, a major problem remains for understanding human cooperation, because humans cooperate even in one-shot interactions with unrelated strangers they will never meet again (i.e., where all these former theories don’t seem to work). Of course, it could be that we cooperate even in these situations because we carry on behaving as if interactions are among kin, repeated, or lead to reputation gains – after all, they nearly always were in our evolutionary past and our brain evolved for that social environment, not modern day New York. We may “know” that they are one-shot anonymous encounters, but nevertheless act in part on evolved mechanisms that we cannot simply switch off whenever we like. This is often called the “Big Mistake” hypothesis. Perhaps its not always such a big mistake – it can be very costly in the wrong setting, but often an initial cooperative disposition can help generate positive interactions (see Burnham and Johnson 2005 for more on this hypothesis).
Others have argued that humans are cooperative as a result of group selection. In competition with other groups, groups containing more altruists willing to sacrifice for the good of the group would do well at the expense of groups with only selfish individuals, and thus the cooperative group’s gene pool will grow even though it contains costly altruistic genes. This way, altruism could spread. Of course, whether selection at this group level overwhelms the reproductive advantages of within-group selfishness remains an empirical question – both processes occur in tandem and their relative importance will rise or fall depending on various contexts (e.g. migration rate between groups). So this area remains under heavy scrutiny.
The big question that we did not have time to get into during the WSF panel is the role of religion in human cooperation. At first glance, you might wonder why religion has anything to do with the evolution of cooperation. On the other hand, religions appear to offer the quintessential example of human cooperativeness, even altruism – groups of unrelated people willing to sacrifice extraordinary amounts time, energy and resources in the pursuit of shared cooperation (e.g. norms, taboos, helping the needy, collective action). They therefore pose one of the biggest puzzles for those interested in the origins of human cooperation.
To my mind, the evolution of cooperation and religion must have been tightly linked in our evolutionary history. Here’s why. One of the key things that distinguishes cooperation in non-human animals from cooperation in humans is our advanced cognitive abilities for complex language and “theory of mind” (the ability to reason about the contents of other minds, e.g. I know that you know X). Language and theory of mind dramatically elevate the potential for cooperation via indirect reciprocity, as reputations can now spread like wildfire. People can seek out cooperators and avoid cheats even when they have never interacted or even met them before. Moreover, theory of mind opened up a whole new world for managing our own reputations. Unlike our ancestors, with the evolution of theory of mind we were now intensely concerned ourselves about others finding out about and reacting to our own actions later on. I worry about what you know about me (e.g. do you know I stole your brother’s meat?), or what you saw me doing, or what you heard others saying I did, and so on. The consequences of my actions now depend on others’ knowledge, not just on being observed. At the same time, the potential consequences of being found out became more costly, as punishment became more likely (with more connected eyes and ears) and more severe (with the greater potential for group retribution). With the evolution of language and theory of mind, selfishness took on significantly elevated costs.
With our theory of mind on high alert for other minds observing, discovering, and judging our actions, it was a small step to the belief that our actions were continually watched and judged not only by other human beings, but also by supernatural agents (be they gods, witches, ghosts, sorcerers, spirits or whatever). It appears to be a universal feature of human societies that supernatural agents are believed to observe and reward or punish our actions, or even intentions. On the face of it, this seems like the kind of belief that evolution should stamp out because it compromises our reproductive fitness – forcing us to forgo opportunities for selfishness by following taboos or avoiding temptation. However, a belief that supernatural agents are watching may on the other hand bring adaptive advantages – decreasing the likelihood that we will be discovered and punished for socially unacceptable behavior in the real world. Since punishment could be severe in our pre-industrial societies – banishment, shunning, injury, or even death – evolution may have favored a belief in supernatural agents as a mindguard against selfish behavior. In short, part of humankind’s great propensity for cooperation may stem from the fear of supernatural punishment (further reading on this “supernatural punishment hypothesis”). Even atheists maintain beliefs about the consequences of our actions that are essentially supernatural: superstitions, folklore, “Just World” beliefs, karma, comeuppance, just desserts, and so on. If such beliefs were adaptive in our evolutionary history, their universality and persistence across places and cultures would be no surprise at all.