The Red Queen_ Sex and the Evolution of Human Nature - Matt Ridley [159]
We have modules for learning to interpret facial expressions – parts of our brain learn that and nothing else. At ten weeks we assume that objects are solid and therefore two objects cannot occupy the same space at the same time – an assumption that no amount of exposure to cartoon films will later undo. Babies express surprise when shown tricks that imply that two objects can occupy the same place. At eighteen months babies assume that there is no such thing as action at a distance – that object A cannot be moved by object B unless they touch. At the same age we show more interest in sorting tools according to their function than according to their colour. And experiments show that, like cats, we assume that any object capable of self-generated motion is an animal, something we only partially unlearn in our machine-infested world.16
That last is an example of how many of the instincts in our heads develop on the assumption that the world is that of Pleistocene, before cars. Infant New Yorkers find it far easier to acquire a fear of snakes than of cars, despite the far greater danger posed by the latter: their brains are simply predisposed to fear snakes.
Fearing snakes and assuming that self-propelled motion is a sign of an animal are instincts that are probably as well developed in monkeys as in people. Nor is, for example, the unwillingness of adults to have sex with people with whom they have lived as children – the incest-avoidance instinct – peculiarly human. Lucy did not need a bigger brain for these things any more than a dog did.
The one thing Lucy did not need was to have to start from scratch and learn the world afresh every generation. Culture could not teach her to detect edges in the visual field; it did not teach her the rules of grammar. It could have taught her to fear snakes, but why bother? Why not let her be born with a fear of snakes. It is not obvious to somebody with an evolutionary perspective quite why we must consider learning so valuable. If learning really did replace instincts rather than enhance and train them, then we would spend half our lives re-learning things that monkeys know automatically, like the fact that unfaithful mates can cuckold you. Why bother to learn them? Why not allow the Baldwin effect to turn them into instincts and spend slightly less time going through the laborious business of adolescence? If a bat had to learn to use its sonar navigation from its parents, rather than simply developing the ability as it grew, or a cuckoo had to learn the way to Africa in winter, rather than ‘knowing’ before setting off, then there would be a lot more dead bats and lost cuckoos every generation. Nature chooses to equip bats with echo-location instincts and cuckoos with migration instincts because it is more efficient than making them learn. True, we learn a lot more than bats and cuckoos do. We learn mathematics and a vocabulary of ten thousand words, and what people’s characters are like. But this is because we have instincts to learn these things (with the possible exception of mathematics), not because we have fewer instincts than bats or cuckoos.
The Toolmaker Myth
Until the mid 1970s, the question of why people needed big brains when other animals did not had only really been posed by the anthropologists and archaeologists who study the bones and tools of ancient human beings. Their answer, persuasively summarized by Kenneth Oakley in 1949 in a book called Man the Toolmaker, was that man was a tool-user and toolmaker par excellence