BELIEF SERIES LECTURE

Why God won’t go away

Might religion have an adaptive function in human evolution?

Professor Robin Dunbar

British Academy; Professor of Evolutionary Psychology, School of Biological Sciences, University of Liverpool

14 February 2005

I’m going discuss some ideas we are beginning to have about the evolution of religion, which are coming out of evolutionary psychology and evolutionary biology. Though I work in a biology department, I usually describe myself as an evolutionary psychologist, partly because it brings together the amalgam of biology and evolutionary thinking with psychology in its more conventional sense, and partly because the interest of evolutionary biologists in areas like religion has been absolutely non-existent. These areas have been left principally to the humanities and perhaps the social sciences: the sociologists and anthropologists. Latterly people have started to apply evolutionary thinking to human behaviour in much more detail, and to become interested in areas like religion, which are particularly characteristic of humans. The reason that evolutionary biologists have not previously been bothered about it is, for instance, that there is no evidence that animals display anything that we would want to refer to as religion or religious behaviour. Of course the famous psychologist BF Skinner (1904-1990) claimed to have taught ritual to a pigeon, but it was just taught, unsupported by belief, and clearly it is the belief behind ritual that distinguishes what humans do from behaviour learned in laboratories.

Once the detailed study of human behaviour was under-taken, a number of unusual features were noted. Cultural evolution has become a hot topic, and arising from it, areas like literature and its functions, and religion and music - three things which appear to be utterly unique to humans and, from an evolutionary point of view, prompt the questions as to why they exist and what function they serve.

Today I shall discuss three questions, as summed up in my most recent book The Human Story (2000, Faber), which essentially asks ‘why aren’t humans just great apes’. Something peculiar happened during the course of human evolution when we separated off from the great apes, which made us very different. The answer we reach, ultimately, is religion. The three questions are:

What does religion do for us? The classic evolutionary question: What function does it serve? Why does it exist? What purpose does it serve in the organism’s life, which allows it to survive and reproduce more successfully?

Why is religion unique to humans? Since it does appear to be unique to the human lineage, why haven’t other species developed behaviour that we would recognise as religion?

When did religion evolve? In the time span between our separation from our sister species (the other African great apes, the chimpanzees and gorillas, about seven million years ago), and the appearance of modern man, when did it appear? Of course it is very hard to get any evidence of psychological space. Everything is fossilised, and the first archaeological signals we find for religious behaviour (indeed one of the few things about which archaeologists do agree) is the evidence of deliberate burial with gravesites not much more than 20,000 years ago.

1 What functions does religion seem to serve?

These are not really new, but looking at religious belief and activity, I think there are four major components: it lends coherence to a complex world; it enormously improves psychological well-being; it produces social bonding, creating a sense of belongingness, being part of a community; and last but not least, it enforces conformity - the hellfire and damnation component. Some of these come from within, some from without. Freud mused that these components affect our behaviour in the real world by helping us to step back and cope with its awfulness, tsunamis etc, by providing an interpretative or predictive framework. This ability to assess and survive is uniquely human, without it we might be tempted to look for the nearest cliff.

So what does religion do for us? Depressingly for those who are not religious, it seems that there are huge payoffs to being in a religious framework. This has much more to do with the mind state of being religious, and of being part of a community, rather than going through the rituals of religion, of going to church now and again. There is a lot of new sociological evidence suggesting that actively religious people live longer, appear to be less stressed, suffer fewer psychological problems, and tend to recover faster from illness and major surgery, than those who are not religious in that sense. There are lots of benefits in the more immediate term, but the question is: why should those benefits occur? The options are clearly either supernatural or physical. I suggest the answer is the good old activity of ‘grooming’ in the primate sense. Like humans, primates are highly social animals, which as a group was a big evolutionary break-through that created an intensely social world, within which it solves the problems of successful survival and reproduction. Primate societies are implicit social contractors, who solve life’s problems communally, rather than going it alone. The activity of grooming, far beyond the needs of cleanliness, is very good at triggering the release of endorphins, which are part of the brain’s pain-control system, slow acting and long lasting. Low level monotonously stressful activities like jogging, writing essays (as I tell my students), grooming (actually quite painful by a monkey), even being massaged (initially quite painful, being pummelled about, but then making one relaxed and at peace with the world), somehow release endorphins, though the mechanism is unclear, and make us feel relaxed and contented, in the context of those sharing the activity. The trust so created allows alliances and coalitions to be built. Between humans, grooming tends to be restricted to intimate contact, petting and cuddling etc, one-on-one or within a very small circle of family or friends. Bonding within the wider community seems to be explained by religion.

Many of the rituals of religion seem to be good at releasing endorphins. Taking up slightly awkward postures, be it standing to pray or kneeling to pray, do so in a minor way, but certainly dancing triggers huge opiate releases. Dancing is a major feature of many religions such as performed by the so-called Whirling dervishes of the Sufi sect, the most mystical branch of Islam, to achieve a state of ecstasy. Trance dancing in many traditional societies is exactly the same, and particularly involves rhythmic behaviour often associated with singing. Recent studies now being further developed have shown that singing, music, and laughter produce endorphins. The endorphin levels can be correlated to pain thresholds, now often used as a proxy for endorphin measurement, and were thus assessed by the simple expedient of timing tolerance of discomfort (caused by a frozen wine-cooler held against the forearm, or a blood pressure monitor wrapped around the arm and inflated), before and then after the phenomena being measured. Looking at groups, particularly religious groups, we compared an Anglican group (whose meeting involved prayers, readings and discussion, but with no singing), with a more Pentecostal type (all-singing, all-dancing, arm-waving event). It is unclear quite what was happening in the Anglican event, though it did produce a small pain-threshold effect, but in the other group, though interestingly it started at a higher level, the endorphin effect was considerable. We have discovered that opiates are very good at tuning the immune system, which seems to explain these beneficial effects.

Somehow this capacity to produce opiates has been captured and turned to good use, and religion has somehow been logged-on to that, to provide an explanation for its continuance. An experiment with laughter (another unique feature of humans), compared two types of audience: one of which was shown a rather boring documentary video for twenty minutes, and the other, videos of Frank Skinner or Mr Bean. Those seeing the documentary experienced no change in pain tolerance, but those who had laughed could stand the wine cooler for up to 100 seconds longer.

Laughter is good for you

The question then is: why do this in the context of the cooler for up to 100 seconds longer. Laughter is good for you religion? Why not just flagellate yourself in the local gym or on your own (as lots of people do)? The answer goes back to the nature of primate sociality. It is interesting to look at primates in general, and at their typical group sizes, and plot those against the relative size of the neocortex.

The neocortex is a narrow sheath, 5 to 6mm deep, which lies over the inner, more primitive mammalian brain - measuring in our case about 1 sq metre, wrinkled so that it can wrap around our relatively small ancestral brain – and is a primate speciality, where all the smart stuff is done, in effect the thinking. In mammals in general, the neocortex accounts for 10% to 50% of total brain volume; in primates, it starts at 50%, rising to 80% in humans. It transpires that there are clear correlations between social group size, and indeed many other aspects of primate behaviour connected with sociality (grooming habits, subtle social strategies in getting their way, social play, etc) and relative neocortex volume. Humans sit very nicely at the top of this graph, as it would predict, with a group size, based upon our neocortex size, of about 150, experienced as the number of people we know well enough to ask of them a favour without fear of a slap in the face, though it may not be easy and may create a sense of obligation. The structure of these social networks, whose numbers vary between individuals from about 100 to about 300, may be seen as a series of expanding circles. The individual sits at the centre of a very intimate circle containing about 3 to 7 people, outside which is another circle containing another 10 individuals, with further layers outside, all of them very tightly scaled and in a very fixed ratio of three, for reasons which we don’t quite understand.

The sizes of these circles seem to correspond to the fault-lines of relationship intensity that you have with these people, and also to the frequency with which you interact with them. This seems to be the natural grouping for all primates. In the inner circle, favours can be obtained without the expectation of a return favour, but as you move further out, the relationships become much weaker. As a corroboration of these scales, an experiment carried out with 43 long-suffering participants showed, in spite of huge variations, that they sent an average of 68 Christmas cards to an average of 153 recipients, corresponding closely with the human group size of 150.

The problem with these very large groups, with social contract systems, like those of primates in general and humans in particular, is that if free-riders (those that take the benefits of sociality, but don’t pay the costs) get loose in the system, they can easily destroy it. The whole basis of social contract systems is that you are prepared to forego some of your immediate personal demands in the interests of a greater payoff in the long run. You must trust others that they too will pay that cost at the same time, and bank on their own long-term payoff. Individuals can always cheat on such a system, expecting the long-term benefits while avoiding theshort-term costs. On a small scale, this can be not buying their round in the pub; not quite paying all their taxes; parking on a double yellow line when they pop into the post office for a stamp or a paper shop for a paper, thus preventing an ambulance from parking. On a larger scale, it can be seen as deforestation or exploitation of non-renewable resources. All these are free-rider type problems. It is easy to show, as in a computer model, that the scale of free riding is affected dramatically by the size and dispersion of the society. The larger and more dispersed it is, the easier it is for the free-rider to find naïve individuals to exploit, because they haven’t encountered the free-rider’s various activities. If we look at hunter-gatherer communities today of 150 members, we see that they don’t all live in one place, but are scattered in several smaller groupings which come together now and again, but with the opportunity to move from one group to another. So the success of free riding depends upon two key factors: one is the amount of investment needed to be made in a relationship, the other is how far away the next sub population is. Free riders are successful when coalition time (investing in a relationship) is low, and they can easily exploit other individuals; similarly, when search time is low, they can quickly move from one group to another. Where these low values coincide, no one can be taken on trust and everyone may become a free rider. At the opposite extreme, where it is expensive to form a relationship that provides the benefits of sociality, or where the next group is a very long way away, free-riders tend to get excluded. If we add in to this model a component for information exchange such as gossip, it removes a huge part of the area where free riders were formerly successful.

Another model allows for dialects (the chairman had alluded also to dress, hairstyle and other badges of group membership) and it can be shown that with minimal dialect change, the population, after 20 generations, is taken over by free-riders, whereas when a dialect is difficult to learn and changes by some 50% each generation, free-riders can’t cope. Thus we see that, although language is intended for communication, dialects are inward focused, hard to learn, and change very fast. Liverpool ‘Scouse’ of Beetles’ days in the 60s is unrecognisable today, after only one generation.

So, how might religion function in terms of controlling free riders? The answer is found at two levels. One is the threat of punishment, but the really important one is that it creates the sense of belonging to a group. To engage in these activities, these rituals, as a group, creates a sense of bonding and of community that makes one much more willing to toe the social line, and to engage in these kinds of obligations to other members of the group - all through the effect of the endorphins. Religion provides a reason for doing it as a group. Rather than exercising on five different running or rowing machines to get a social pay-off from the opiate surge, one must engage as a group, as we do in dancing. Trance dancing is widespread as a format in traditional religion, which draws everyone in.

2 Why is religion unique to humans?

This largely has to do with brain size. One of the features in

psychology during the last decade or so is the idea of intentionality. We can somehow read each other’s minds, and we do so in a reflective kind of way. In the 1^st order of intentionality, Jack has a mental state. In the 2^nd order, Jill has a belief about Jack’s belief. This can be an infinite regression; in the 3^rd order, Jack believes that Jill believes that he believes whatever it may be. Prior to age 4 to 5, children are in 1st order of intentionality, and know only their own beliefs. Much literature is produced on children of 4 to 5, and we don’t really know how high one can reach thereafter in the hierarchy of intentionality, but we seem to find that people can’t cope beyond level 5. These results vary between individuals, but interestingly it transpires that those who enjoy more intense relationships with more individuals tend to manage performances in higher orders, and tend to come typically from core clique sizes of about five people. This probably explains why we need the metaphysical structures to religion. There are two key issues. One is belief in an unseen world that is counterfactual, with miracles etc. that does seem to need at least 2^nd order intentionality. The other concerns belief in moral injunction. All levels of belief seem to equate with different levels of intentionality. Personal belief, at the 3^rd order, can imply ‘I believe that God wants me to act with righteous intent.’ These can be made into a social phenomenon, as opposed to purely personal, by adding another layer ‘I intend that you believe that God wants us to act with righteous intent.’ But it seems that for religion as we really know it, we need to get up to the 5^th order, to make it communal, as opposed to purely social, and this may explain why we have the 5^th orders, since in our everyday relationships we don’t get much above the 3^rd.

Theory of Mind
Hierarchical nested levels of intentionality.

2nd level:
‘theory of mind’
at age 4-5 years.

‘I intend that you believe that I
suppose that...’

The question arises as to whether the capacity for achieving different levels of intentionality may be a function of brain size, particularly neocortex size, which is a critical factor in what is referred to as social brain psycholosis. Studies suggest that the neocortex has evolved from the back to the front, the smart area. The frontal lobe, (sometimes known to psychologists as the executive brain), may be the location of the critical hardware. It is precisely in the more forward part of the brain that we start to find evidence for 2^nd order intentionality in non humans, Apes are the only species examined which show any such evidence, and humans, by lobe volume produces a straight-line correlation, demon-strating why only humans believe, and may allow us to enquire as to when religion evolved.

Significant spare capacity in non-visual cortex starts to become available at great ape brain size & becomes exponentially available there-after. So is it surprising that theory of mind is first seen only among Great Apes?

3 When did religion evolve?

If we can estimate frontal lobe volume for fossil hominids, we can work out when they achieved 3^rd, 4^th and 5^th order intentionality, as brain size increased during the course of human evolution. In fact we have lots of data on cranial volumes, from which we can estimate brain volume, and from that frontal lobe volume, since they are tightly locked in together; and from that we can estimate intentionality level. From this process we can draw a chart showing the Australopithecenes (Lucy and all her kind), hovering at the 2^nd order level with the great apes, then we see the genus Homo, the upright ape (Homo erectus), but the evolution is slow, and it is not until the appearance of archaic humans (H sapiens) that we see them rising above the 4^th order towards the 5^th order with the appearance of modern humans, such as Cro-Magnon from about 100,000 years ago. We notice that the Neanderthals’ brain size was very large, but it grew from a much smaller size while they were in Europe, and seems to be have been organised in a different way, with less frontal lobe than ourselves. In terms of the evolution of religion from fossil records, it appears only to come with modern humans as evidence in cave paintings, and is often associated with trance dancing that we see still today, and later with the grave goods, which were associated with anatomically modern humans of the last 100,000 years.

In conclusion, religion probably evolved to facilitate social cohesion in very large groups of the kind that came to dominate our social evolution. As a social phenomenon it is extremely demanding and might have stimulated the increase in brain size. It probably evolved only in modern humans, not before 200,000 years ago. If religion has this social function of making society more cohesive, and if we forget for a moment the metaphysical sense that most people regard as important for religion, and do away with the theology, what on earth do we replace it with, to create that same sense of social commitment within the group?

To that question, I’ll leave you to tell me the answer.

Summary by Martin Sturge