An area of controversy in the life sciences relates to the relative roles of genetics and the environment. Confusion commonly afflicts politics. For example, early Communists glommed on to the discredited genetic theory of “inheritance of acquired characteristics.” This theory holds that changing a person’s attitude and behavior would somehow result in changes to his or her genes, which would allow for genetic transmission of the changed attitudes and behavior to his or her children. For this idea to be true, outside influences on the brain would have to change the genes not only in brains but also in the sex cells (sperm and egg cells). The idea was held in ancient times by Hippocrates and Aristotle, but it gained scholarly imprimatur with formal publication in 1809 by Jean-Baptiste Lamarck. In the 1930s, the Russian president of the Soviet Academy of Agricultural Sciences, Trofim Lysenko, applied the doctrine to Soviet agriculture with disastrous results. At the same time, Soviet political leaders extended the mistaken doctrine to inheritance of educational and social experiences; that is, changing human nature by government policy. They expected that indoctrinating the current generation in collectivism would genetically transfer collectivist attitudes and behavior to all future generations. Cuba, North Korea, and China showed that collectivism can be transferred culturally but not biologically.
In the United States, much political angst arises from disputes over whether more effective educational and social policies will succeed in lifting people out of poverty and dysfunctional behaviors. When I was a child, I often heard the axiom, “You can take the boy out of the country, but you can’t take the country out of the boy.” Today, the corresponding axiom would seem to be, “You can take the boy out of the ghetto, but you can’t take the ghetto out of the boy.” The reality is that you can take the country or ghetto out of the boy, but this won’t transfer to his children by his genes.
What we are now discovering is that environment and experience affect the expression of genes. Whether or not genes are accessible for readout often depends on the environment. People have underestimated their capacity to sculpt their own brains, attitudes, and behavior by controlling experiences that affect gene expression. Though people may control to some extent how their own genes are expressed, there won’t be any biological transfer to their heirs. Environmental and cultural influences do of course transfer, so one’s heirs can be taught how to likewise exert control over how their genes are expressed.
Having the right chemicals in the right environment at the right time is believed by most scientists to be all that is needed for creating life and shaping the mental life of the individual. To them, life seems like a highly improbable occurrence. But it did happen, and even more improbable, there may be a life force that sustains it.
Many scientists also think of the brain’s conscious mind as an emergent property of brain function. Emergent properties follow the rule that the whole is greater than the sum of its parts. Another way of saying this is that the properties of the whole cannot be predicted from what you know about the properties of the contributing parts. Yet, paradoxically, most scientists believe that as they learn more and more about less and less, they will somehow explain the whole.
Emergent properties apply both to molecules in a primordial soup that generate simple living organisms and to the 87 billion or so neurons of a human brain that generate a conscious mind. A physical world that can generate emergent properties is a mysterious and magical world indeed.
What gets left out in such consideration is the capacity for personal control over one’s biology, which is an important theme. I contend that at the level of the individual person, mind itself—especially conscious mind—is a major force of natural selection that drives creation of mental capacity and character. The implications for daily living could not be more profound. Accepting one’s biology and circumstance breeds helplessness and fatalism. So, it boils down to one’s belief system. Either you are “captain of your own ship, master of your own fate,” or you are shackled by the belief that change is not possible. What you think and do shapes your brain's function.
Excerpted from Mental Biology. The New Science of How the Brain and Mind Relate, by W. R. Klemm. New York: Prometheus. See rave reviews at WRKlemm.com, click on "author."
No comments:
Post a Comment