Our inner ape

I have always enjoyed reading the work of Frans de Waal, a primatologist who focuses on the social structure and psychology of apes, particularly the two chimp species, and monkeys. His previous books, Good Natured: The Origins of Right and Wrong in Humans and Other Animals, The Ape and the Sushi Master: Cultural Reflections of a Primatologist, and Peacemaking among Primates have all entranced me and inspired my reflections on such diverse topics as evolutionary psychology, the origins of political and social structures, and, of course, the evolution of religion.

His recent book, Our Inner Ape, is, in many ways the culmination of his work. He shows a real love for his subjects, particularly the "pygmy chimps", the bonobos. What follows is my impressions of the book and subsequent ruminations, not a full review, but I do recommend you read it.

De Waal first outlines the history of attempts to draw conclusions from our cousins about human nature, in particular Desmond Morris's execrable "violent ape" account. He points out the basis for evolutionary inference is based on shared ancestry, not on analogies (which can be drawn across any number and distance of evolutionary branches as you like, without constraint). We share ancestry with chimps and bonobos, but they are themselves the product of 6 million years of independent evolution, so who knows what changes they have undergone from our most recent common ancestor?

But we want to know about our own biologically constrained behaviour, and this is difficult to do, because culture gets in the way, both of the subjects being studied, and of the investigators. So studying the behaviour of these apes may give us some indications of what it is we all share as a kind of ape ourselves.

And what he finds is remarkable. Instead of violence, unceasing competition, male aggression, and what have you that are given as the "typical" ape nature, de Waal and those he relies on have found that apes are not all the same, and that they are caring, xenophobic, male dominated (chimps), female dominated (bonobos), able to care for other species (like the female gorilla Binti, who in 1997 at Chicago picked up and cradled a boy who fell into the gorilla enclosure, and took him to the door for the keepers to retrieve), and able to plot murder.

In short, as the subtitle of the book puts it, apes evince the best and worst of human nature.

De Waal is able to perspicaciously identify differences in the ways that peace is made amongst these species: chimps often make peace after conflict by females interfering in alpha male aggression, but more often than not, it is post-conflict that the males themselves patch things up (literally, sometimes - one chimp attacked his keeper, but came up later to push the wounds together, making the characteristic pantgrunts of chimp mollification). But in bonobos, the females do the peacemaking. Why? It has to do with the allocation of sex. In chimps, the alpha male controls who gets access to females, and must jealously guard that right. But in bonobos, sexual activity is ubiquitous. Males cannot control it (and often engage in same sex activity), because nobody does, so sex has evolved to become a social cohesive mechanism, involving even immature individuals.

What does this mean for humans? Obviously, we are neither alpha-male organised troops, nor profligate sexual encounterers, but the underlying logic, of what the role of sex (rather than reproduction) is in a social species, still applies. We are mostly monogamous, and so controls happen in a different way. Instead of protecting one male's access to sex, or using it as a casual greeting, we use sex to maintain nuclear and to a lesser extent extended family structure (if you sleep with my daughter, then you are part of my family, whether I like it or not).

De Waal doesn't romanticise his subjects: he was greatly affected by the political murder of the alpha male Luit at the Arnhem Zoo where he worked before moving to the United States. He interprets this, and he is right to do so, as the outcome of a political alliance between the old alpha male and a challenger. In short, they plotted a coup.

Sex, it turns out, is closely related to power relations amongst apes, although what role it plays depends on the social structure of the ape species in question. And "power relation" isn't quite right, either, because it implies all kinds of postmodern or social epistemological theories that aren't needed here. It is better to just call this what it is: social dominance psychology.

Social animals form hierarchies based on access to sex and resources such as food, territory or safe places. Humans are clearly social dominance apes, but we don't closely follow either the bonobo or chimp model, and as for the gorillas, who have a bull male as alpha with a harem of females to which he controls all (or nearly all, about 15% of progeny are the result of "sneaky matings" by males who live on the periphery of the troop) sexual access, well, that only works for Ottoman emperors and the like.

De Waal says this:

Bonobos show us the conditions under which peaceful relations between groups may evolve. Similar conditions apply to us. All human societies know intermarriage, hence gene flow between groups, which makes deadly aggression counterproductive. Even though one may gain by defeating another group over territory, there are drawbacks, such as lives lost on your own side, kin killed on the other side, and reduced trading opportunities. The latter may not apply to apes, but it is a significant factor in the human case. [p141]

At this point I am reminded of the claim made in James Shreeves' The Neandertal Enigma: Solving the Mystery of Modern Human Origins, that what humans do better than neanderthals is move long distances and trade, across thousands of kilometers. This has an enormous impact on our nature. We share tools, ideas and genes and that is a reason why we aren't murderous apes.

As we watch the media, we get the impression that human beings are the most murderous species on the planet, but if you think about it, from a sample of 6 billion it is highly likely that someone will be behaving badly; that doesn't license the inference that we are uniformly badly behaved. If you are worried by the media reports, then stop watching the media ("Doctor, it hurts when I do this." "Then don't do that."). But the individual experience of violence outside failed societies is relatively rare. The most violent societies on earth have a murder rate of under one per thousand, most under one per ten thousand, and my own nation 15 per hundred thousand. The average experience of violence in Australia, regarded by many as one of the most violent developed nations, is 1,000 per hundred thousand. So an individual has a one in a hundred chance of encountering violence. Assume that this is localised into criminal social groups and alcohol addictive families, and the rest of us have a much lower likelihood of violence being done to us.

So mostly we live in peace, even in high density populations. And it makes sense - we cannot trade or intermarry if there is persistent violence between groups, and that's what humans do best, as Tigger might say. As de Waal notes [164ff], it is a Malthusian myth that we are violent in high density populations (based on the overextrapolation from rats, which use pheromonal triggers, to humans, which, mostly, don't). Many other primates aren't affected by high density, either, such as rhesus monkeys. What makes the difference? Grooming. Monkeys and apes groom each other, and so do we, although we call it remedial massage, hairdressing, clothing, social interaction and a host of other activities we might not otherwise connect.

As I have said before, I think religion is a form of this. As social grooming, we strengthen our social bonds by sharing rituals and beliefs, talking about them, preaching them, and studying them. A friend even thinks that music is a form of social grooming, although he puts it as a way to coordinate social groups, both rhythmically and socially. A musician and neurobiologist, William Benzon, in his Beethoven's Anvil: Music in Mind and Culture, held that mutual coordination in dance, playing music, and the occasions organised around musical performances, held societies together. It is no accident that religious rituals involve music, if he is right.

Finally, note that exchange, or trade, which has by economists been modelled as an iterated Prisoner's Dilemma of rational agents, holds true enough for chimpanzees, but less so for humans. It seems that we aren't, in a fine irony, as rational as chimps. We will tend not to cheat as much as they do, and will care for our conspecifics when it is not necessarily in our individual interests to do so. This makes sense only if our behaviours, our cognitive and social libraries, are the result of selection for cooperative behaviours rather than the Malthusian competitive ones that we all associate with evolution. Not to make a group selectionist argument here (I am not group selectionist myself), but fitness is enhanced for all if we tend to be cooperative.

There's a lot of work to be done about human nature that is both evolutionarily grounded and free of the standard myths and mistakes of the past. De Waal is one of those doing this work (Marc Hauser is another, although I don't agree that there is a moral grammar as such). Call it sociobiology if you must, but we need, rather urgently, to understand our nature as a species, and that means understanding what our species has adapted to in the past, and why.