The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature Read Online Free PDF Page A

another ninety-five thousand years. How could evolution favor the expansion of a costly organ like the brain, without any major survival benefits becoming apparent until long after the organ stopped expanding?
    The third problem is that nobody has been able to suggest any plausible survival payoffs for most of the things that human minds are uniquely good at, such as humor, story-telling, gossip, art, music, self-consciousness, ornate language, imaginative ideologies, religion, and morality. How could evolution favor such apparently useless embellishments? The fact that there are no good theories of these adaptations is one of science's secrets. Linguistics textbooks do not include a good evolutionary theory of language origins, because there are none. Cultural anthropology textbooks present no good evolutionary theories of art, music, or religion, because there are none. Psychology textbooks do not offer any good evolutionary theories of human intelligence, creativity, or consciousness, because there are none. The things that we most want to explain in any evolutionary framework seem the most resistant to any such explanation. This has been one of the greatest obstacles to achieving any real coherence in human knowledge, to building any load-bearing bridges between the natural sciences, the social sciences, and the humanities.
    These three problems compound one another. They roam around like a gang, knocking the sense out of any innocent young theories that happen to stroll along. If a new theory overcomes problem three by claiming a previously unrecognized survival benefit for art or language, then problem one raises the objection, "Why do we not see hundreds of species taking advantage of that survival benefit by growing larger brains with these abilities?' 5 Or, suppose a new theory tackles problem two by emphasizing the success if our early Homo erectus ancestors in spreading from equatorial Africa across similar latitudes in Asia. Then problem three can point out that many smaller-brained mammals such as
cats and monkeys expanded in similar ways, without evolving such mental embellishments.
Most theories of human evolution attempt to solve only one of these three problems. A few might solve two. None has ever solved all three. This is because the three problems create a paradox that cannot be solved by thinking in terms of survival of the fittest. Many human mental abilities are unique to our species, but evolution is opportunistic and even-handed. It doesn't discriminate between species. If our unique abilities must be explained through some survival benefit, we can always ask why evolution did not confer that same benefit on many other species. Adaptations that have large survival benefits typically evolve many times in many different lineages, in a process called convergent evolution. Eyes, ears, claws, and wings have evolved over and over again in many different lineages at many different points in evolutionary history. If the human mind evolved mostly for survival benefits, we might expect convergent evolution to have driven many lineages toward human-type minds. Yet there is no sign of convergent evolution toward human-style language, moral idealism, humor, or representational art.
In The Language Instinct, Steven Pinker claimed that the elephant's trunk raises some of the same problems as human language: it is a large, complex adaptation that arose relatively recently in evolution, in only one group of mammals. Yet the elephant's trunk does not really raise any of our three problems. There was convergent evolution towards grasping tentacle-like structures among octopi and squid. The evolution of the trunk allowed the ancestors of the elephant to split apart very quickly into dozens of species of mammoths, mastodons, and elephants, in an evolutionary pattern called an "adaptive radiation." These species all had trunks, and they thrived all over the globe until our ancestors hunted them to extinction. An elephant