The Red Queen_ Sex and the Evolution of Human Nature - Matt Ridley [162]
The evidence for neoteny is extensive. Human teeth erupt through the jaw in a set order: the first molar at the age of six, compared with three for a chimpanzee. This pattern is a good indication of all sorts of other things because the teeth must come at just the right moment relative to the growth of the jaw. Holly Smith, an anthropologist at the University of Michigan, found in twenty-one species of primate a close correlation between the age at which the first molar erupted and body weight, length of gestation, age at weaning, birth interval, sexual maturity, lifespan and especially brain size. Because she knew the brain size of fossil hominids, she was able to predict that Lucy would have erupted her first molar at three and lived to forty, much like chimpanzees, whereas the average Homo erectus would have erupted his at nearly five and lived to fifty-two.25
Neoteny is not confined to man. It is also a characteristic of several kinds of domestic animals, especially dogs. Some dogs are sexually mature when they are still stuck in an early phase of wolf development: they have short snouts, floppy ears and the sort of behaviour that wolf pups show: retrieving, for example. Others are stuck at a different phase: longer snouts, half-cocked ears and chasing, like sheepdogs. Still others have the full range of wolf hunting and attacking behaviours, plus long snouts and cocked ears: Alsatians, for instance.26
But whereas dogs are truly neotenous, breeding at a young age and looking like wolf puppies, humans are peculiar. They look like infant apes, true, but they breed at an advanced age. The combination of a slow change in the shape of their head and a long period of youthfulness means that as adults they have astonishingly large brains for an ape. Indeed, the mechanism by which apemen turned into men was clearly a genetic switch that simply slowed the developmental clock. Stephen Jay Gould argues that rather than seek an adaptive explanation of features like language, perhaps we should simply regard them as ‘accidental’, though useful, by-products of neoteny’s achievement of large brain size. If something as spectacular as language can be the product of simply a large brain plus culture, then there need be no specific explanation of why larger brains are required, because their advantages are obvious.27
The argument is based on a false premise. As Chomsky and others have amply demonstrated, language is one of the most highly designed capabilities imaginable, and far from being a by-product of a big brain, it is a mechanism with a very specific pattern that develops in children without instruction. It also has obvious evolutionary advantages, as a moment’s reflection will reveal. Without for example, the trick of recursion (subordinate phrases) it becomes impossible to tell even the simplest story. In the words of Steve Pinker and Paul Bloom, ‘it makes a big difference whether a far-off region is reached by taking the trail that is in front of the large tree or the trail that the large tree is in front of. It makes a difference whether that region has animals that you can eat or animals that can eat you.’ Recursion could easily have helped a Pleistocene man survive or breed. Language, conclude Pinker and Bloom, ‘is a design imposed on neural circuitry as a response to evolutionary pressure’.28 It is not the whirring by-product of the mental machine.
The neoteny argument does have one advantage: it shows a possible reason why apes and baboons did not follow man down the path to ever bigger brains. It is possible that the neoteny mutation simply never arose in our primate cousins. Or, more intriguingly, as I shall explain later, the mutation may have arisen but never had a reason to spread.
Gossip’s Grip
Those outside anthropology had never paid much obeisance to man-the-toolmaker or any other explanation for intelligence. For most people, the advantages of intelligence were obvious. It led to more learning and less instinct, which meant that behaviour could be more flexible, which was rewarded by evolution. We have