my genome, my self

Artigo do psicólogo de Harvard STEVEN PINKER, publicado em janeiro na NYT Magazine, trata do impacto do descobrimento do genoma humano sobre a identidade pessoal, e sobre as vantagens, os limites e os riscos das informações genéticas das predisposições tanto para os traços de personalidade quanto para as doenças hereditárias.

[...] With the genome no less than with the Internet, information wants to be free, and I doubt that paternalistic measures can stifle the industry for long (but then, I have a libertarian temperament). For better or for worse, people will want to know about their genomes. The human mind is prone to essentialism — the intuition that living things house some hidden substance that gives them their form and determines their powers. Over the past century, this essence has become increasingly concrete. Growing out of the early, vague idea that traits are “in the blood,” the essence became identified with the abstractions discovered by Gregor Mendel called genes, and then with the iconic double helix of DNA. But DNA has long been an invisible molecule accessible only to a white-coated priesthood. Today, for the price of a flat-screen TV, people can read their essence as a printout detailing their very own A’s, C’s, T’s and G’s.

A firsthand familiarity with the code of life is bound to confront us with the emotional, moral and political baggage associated with the idea of our essential nature. People have long been familiar with tests for heritable diseases, and the use of genetics to trace ancestry — the new “Roots” — is becoming familiar as well. But we are only beginning to recognize that our genome also contains information about our temperaments and abilities. Affordable genotyping may offer new kinds of answers to the question “Who am I?” — to ruminations about our ancestry, our vulnerabilities, our character and our choices in life. [...]

[...] None of us know what made us what we are, and when we have to say something, we make up a good story. An obvious candidate for the real answer is that we are shaped by our genes in ways that none of us can directly know. Of course genes can’t pull the levers of our behavior directly. But they affect the wiring and workings of the brain, and the brain is the seat of our drives, temperaments and patterns of thought. Each of us is dealt a unique hand of tastes and aptitudes, like curiosity, ambition, empathy, a thirst for novelty or for security, a comfort level with the social or the mechanical or the abstract. Some opportunities we come across click with our constitutions and set us along a path in life.

This hardly seems radical — any parent of more than one child will tell you that babies come into the world with distinct personalities. But what can anyone say about how the baby got to be that way? Until recently, the only portents on offer were traits that ran in the family, and even they conflated genetic tendencies with family traditions. Now, at least in theory, personal genomics can offer a more precise explanation. We might be able to identify the actual genes that incline a person to being nasty or nice, an egghead or a doer, a sad sack or a blithe spirit.

Há, sim, um viés no artigo de Pinker, no sentido de menosprezar as influências do contexto social, como se, pelo fato de pessoas crescerem no mesmo ambiente familiar e cultural, devessem igualmente compartilhar o mesmo perfil psicológico e comportamental, salvo pelas diferenças genéticas. Falta a ele considerar variações mais sutis, mesmo quando tomadas as diferenças entre irmãos gêmeos, no que diz respeito a aspectos inconscientes vinculados à história pessoal e aos papéis familiares reservados a cada um. Note-se no segmento a seguir:

The discoveries of behavioral genetics call for another adjustment to our traditional conception of a nature-nurture cocktail. A common finding is that the effects of being brought up in a given family are sometimes detectable in childhood, but that they tend to peter out by the time the child has grown up. That is, the reach of the genes appears to get stronger as we age, not weaker. Perhaps our genes affect our environments, which in turn affect ourselves. Young children are at the mercy of parents and have to adapt to a world that is not of their choosing. As they get older, however, they can gravitate to the microenvironments that best suit their natures.

As influências mais importantes para a formação da personalidade - afora as genéticas - são aquelas que ocorrem nos primeiros estágios da infância, o que vem sendo comprovado inclusive pelos neurocientistas, que identificam nestes estágios a formação das conexões neuronais que serão mais perenes, e que determinarão fortemente as representações e os afetos no futuro. Não há dúvidas de que outros fatores se agregarão ao longo da vida, mas eles estarão sempre sobrepostos aos fundamentos estabelecidos. Assim, as predisposições biológicas não se resumem às genéticas, mas incorporam aquelas resultantes de experiências precoces estressantes ou gratificantes, tanto umas quanto as outras gravadas indelevelmente no tecido neuronal, ou no psiquismo, o que, em última instância, são a mesma coisa. (mais aqui)

Entrevista de Steven Pinker a Jorge Pontual, no programa Milênio (aqui) de 10/02/2009, sobre psicologia evolucionária.