Thursday, October 9, 2008

Healthful Incentive

As a fan of Steven Pinker I have come to appreciate his supposition that personality is mostly determined by genetics. He argues convincingly against the idea of the "Tabula Rasa" or the blank slate when it comes to perceiving newborns. He argues that a person's genetic makeup automatically provides them with a pre-programed set of potentials (in the form of wired neural networks), that the environment then acts on to form overall personality. The point is best illustrated in studies of twins separated at birth who share uncanny personality traits even when they have never met. This is illustrated in the above cartoon by Charles Addams. After reading Pinker's book "The Blank Slate: The Modern Denial of Human Nature" I was convinced of this assertion. As I am still. However, it is dangerous to extend this way of thinking to all facets of human life. It perpetuates the chilling echoes of eugenics and gives people the hopeless feeling of being stuck in a world of genetic determinism.

This is not the case with many ways in which our phenotypes brush up against the outside world. I had this realization in two waves over the past 24 hours. First as I watched a man who had spent the last 8 years weighing over 300 pounds loose 180 pounds in a matter of a few months on the show the biggest loser, and second when I read this article about how the cancer epidemic in the west might be curbed by lifestyle changes. The most powerful message in this article is that genes people are born with only affect 15% or fewer instances of cancer. By changing our lifestyles we can dramatically lower our risk of cancer.

Dr. David Servan-Schreiber: "The most recent studies show that: 15 percent at most of all cancers are due to genetic factors - and only partially. Eighty-five percent are not. Nonetheless, cancer strikes families: a notable study published in the New England Journal of Medicine showed that children adopted at birth who were born of parents who died of cancer before age 50 presented the same level of cancer risks as their adoptive - not their biological - parents. What is transmitted from generation to generation are habits and environmental conditions. Not the genes responsible for cancer."
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