Charles Darwin was clear about it. "I am convinced that natural selection has been the main but not the exclusive means of modification," he wrote in the introduction to On the Origin of Species in 1859. Unfortunately, many of Darwin's modern acolytes seem to have forgotten the master's cautionary words and turn one mechanism among several into a totalising theory. Mark Pagel, a distinguished evolutionary biologist, is but the latest. His central concern - and an important one for anyone interested in human history and society - is to understand the origins of those human attributes that mark us out most distinctly from other living forms: our capacities for speech, social organisation and the creation of culture and technology.
Biologists are of course committed to the view that these are evolved properties. For one unorthodox strand of evolutionary theory, whose early protagonist was the Russian anarchist prince Peter Kropotkin but which was championed in modern form by theorists including Lynn Margulis and David Sloan Wilson, this presents no problem: cooperation between individuals and even between species can serve as a motor of evolutionary change. But for the dominant strand of ultra-Darwinists, natural selection works by ruthless competition between individuals of the same species, and any trait must have a selective advantage to the individual - that is, the genes that confer or enable it must have enhanced our ancestors' reproductive success. Hence the problem: how could cooperation, empathy and altruism, even to the extent of sacrificing one's life to save others, increase a person's chance of transferring copies of his or her genes to the next generation?
Pagel's mentor in these matters, Richard Dawkins, distinguished between genes as replicators and organisms as passive vehicles utilised by the genes to ensure their transmission into the next generation. That is, you and I are merely our genes' way of making copies of themselves. Dawkins, and following him Pagel, then introduces two mutually contradictory hypotheses to solve the problem of culture and seemingly non-adaptive traits. The first proposes that culture enhances our genes' chances: the typically masculinist example is that being good at art or music ("brain candy", says Pagel) or having a reputation for valour serves a man like the peacock's tail serves the peacock - a sign to the female that its owner carries good genes and therefore is worth mating with. When writing in this mode, Pagel suggests that, just as organisms are survival vehicles for genes, so social structures - such as groups or tribes, which require a degree of mutual trust and cooperation - are cultural survival vehicles for their members, and hence their genes. Thus a group's culture is part of each individual group member's extended phenotype.
The second, contradictory hypothesis is that culture is an autonomous life form; it consists of units like genes, called memes, that inhabit an individual's mind and are transmitted between individuals through our unique powers of communication. Typical memes are advertising jingles or fashion practices, such as wearing baseball caps backwards. Notoriously, Dawkins proposed, and Pagel follows him, that religion too is a meme - but in this case an infective, hostile virus that poisons the minds it takes over. But as a coherent theory, memeology is about as convincing as Scientology; anything that can embrace religion, advertising jingles and fashions in headwear as if they are all examples of the same unitary thing, a meme, which can jump from brain to brain, should have been laughed out of court years ago, as philosopher Mary Midgley has cogently argued.
In Wired for Culture, Pagel employs both these hypotheses in broad speculations ranging from the evolutionary motivations of suicide bombers to the origins of speech, without apparently recognising that they are contradictory. Confusions of level abound, as when Pagel says: "Our brains can effortlessly think..."But it is we who think, using our brains. Written in a patronising tone and replete with fairy stories about Pleistocene men cooperating by agreeing that one should sharpen spears while the other chips stone hand axes (presumably the women are home doing the cooking as usual), the book misses entirely one of the most convincing arguments for the evolution of human sociality, centred on human mothers' unique preparedness to share the parenting of their children (called "alloparenting" by the evolutionary biologist Sarah Blaffer Hrdy). Grand unitary theories of everything used to be the province of physicists. It's a pity that biology has shed its modesty; we have enough to say about things we do know about without trying to take over the world.
Wired for Culture: The Natural History of Human Cooperation
By Mark Pagel
Allen Lane, 432pp, £25.00
Published 1 March 2012