Oct 17, 2002

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Understanding the Human Brain

The likelihood of comprehending the brain at the neurological level in a way that can help us solve major social problems is small.
By Charles Crawford

The human brain is the most complex structure known to man. Everything
that we do, and have done, is the result of our brain activity. Hence, some people hope that the neurosciences, especially cognitive neuroscience, can provide solutions to some of our social problems.

The neurosciences may provide solutions to some troublesome medical problems, but there are two reasons why I do not believe they will provide solutions to our most urgent social problems. At the neurological level the human brain is very complex - 10 billion neurons - more possible interconnections than molecules in the known universe. The likelihood of comprehending the brain at the neurological level in a way that can help us solve major social problems is small, indeed. But even more important is the issue of context. Biological altruism is self destructive behaviour performed for the benefit of others. So the same act can be an act of terrorism or altruism depending on one's point of view. I believe this distinction would be hard to make at the neurological level.

When I think of the human brain I do not think of neurons interacting with each other, or about hormones and neurotransmitters. I think of it as a set of tools, equipment for recognizing relatives, choosing mates, displaying dominance, defending territory, saving face, deceiving ourselves so that we can better deceive others, etc., that evolved across evolutionary time, aiding the replication of the genes that code for them.

Moreover, I do not think of the brain as the assemblage of neurons that exists today. I think of it in terms of older brains that are embodied within it: brains of Homo Erectus and Homo habilis, and the brains of their ancestors. It is this mysterious and dangerous tool kit that we must focus on if we are to reduce war, poverty, economic depression, and the exploitation of the environment.

But how should we think of the instruments in our brain's tool kit? Evolutionary psychologists think of them in terms of information processing decision makers. The mating tactics of the male scorpionfly provide a simple model. Males present a dead insect to a female and mate with her as she eats it. If they cannot find one, they produce a proteinaceous mass and exchange it for a mating. But they must compete vigorously with other males for the dead insects and the resources to produce the proteinaceous masses. If they can't compete, they attempt to copulate forcibly. All males are capable of all three behaviours. The one they use depends on their ability to deal with conditions in their immediate environment. Forcible copulation would not exist in a rich environment. Moreover, females might desire other types of exchanges, and the males might like to provide them, but their evolutionary history limits them to only these three.

We can think of our brain's tools in terms of innate mental mechanisms: innate schoolmarms, for helping us learn about the world and how to interact with it. Some of our mental tools may have evolved during the last 100,000 years, but many have a million or more years of history. In either case, the environmental conditions they evolved to respond to may be long gone. It is these ancient mechanisms and their functioning that we must learn to manage.

Most of our mental tools are adaptive-culturally variable, and function as they have always functioned. They give us language, gossip, reciprocity, strategies for choosing mates, marriage, self-deception, warfare, and the tens of thousands of other things we do as humans. However, stresses from the environment can overwhelm our tools. True pathologies, such as autism or schizophrenia, occur when circumstances damage tools that are indispensable for living in both past and present environments.

Pseudopathologies result when a tool that produced adaptive behaviour in ancestral environments creates behaviour that is noxious or socially sanctioned in a current environment. For example, prostitution may have its origin in ancestral propensities for trading resources and protection for sex. Obesity may have its origin in ancestral motivations for obtaining fat and sugar. Teen-age gangs may have their origin in ancestral adolescent affiliation behaviours. In the current environment they can be sources of trouble and stress. However, they will be very difficult to completely eliminate, since they are produced by tools that specifically evolved to generate them. Moreover, eliminating them may produce new pseudopathologies or attenuate important behaviours. For example, completely suppressing the trading of sex for resources and protection may increase shoplifting by women, the use of pornography by men, and possibly even destroy the family, as we know it. The vegetarian diet that eliminates obesity may cause anaemia in some people. I am not a proponent of zero tolerance.

Many current behaviours and practices likely did not exist among our ancestors. True altruism, presumed innocent until proven guilty, female infantry, freedom of speech, adoption of genetically unrelated children, democratic government, monogamy, and smoking are likely recent human inventions. Because they are fortuitous effects of tools that did not specifically evolve to produce them, they are volatile - only quasinormal. If we value them, or desire to eliminate any of them, we must work hard at the task. This requires understanding the mental tools that produce them. True altruism and adoption of genetically unrelated children may be the result of kin recognition mechanisms misfiring and delivering help to non-relatives. Monogamy may be the fortuitous effect of ancestral mechanisms for producing sexual jealousy and reciprocity. Smoking may reduce the depression caused by some novel environments.

Some early sociobiologists attempted to develop explanations couched primarily in terms of the history of our reproductive success. I am an unrepentant sociobiologist in that I believe evolutionary history and reproduction are of fundamental importance in understanding human behaviour. I am reformed in that I believe our focus must be on the stresses and problems that our ancestors encountered; the psychological mechanisms that evolved to help respond to them, and the way those mechanisms function now. We need quantitative models of ancestral selection pressures for determining the importance of ancestral reproduction, cross-cultural studies for exploring how evolved mental mechanisms work in different cultures, experimental studies to make causal statements about their functioning, and neurological studies of the structures in which the mechanisms are realized. These studies must be carried out in the context of literature, art, and history because the sciences, in themselves, are not adequate for understanding what it means to be a human being. Moreover, it is through the management of aspects of our social environment that we can manage our ancestral brains.

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