Wednesday, September 14, 2005

Human Brain Still Evolving

Studies in a recent edition of Science by Bruce Lahn of the University of Chicago and colleagues claim that the human brain is still evolving. Specifically, two genes involved in determining the size of the human brain have undergone substantial development in the last 60,000 years, though it had generally been accepted that human evolution stopped around 50,000 years ago. It is not clear how these genes enhance brain function, but they are spreading through the human species as though they confer a competitive advantage.

Given that we don’t know what the genes do and that their evolution is ongoing, this may not have much of a practical impact on most of us. What it does do, however, is suggest that we need to think about this finding – that evolution may still be ongoing in humans – in light of some current topics of public discourse. One such topic is the long standing debate about what is and is not within “normal” psychological parameters. If our brain is still developing it lends credence to the argument that it is better to view differences in human makeup merely as differences as opposed to attaching normative value to them. Another topic related to genetic evolution is the still futuristic notion of genetic engineering in humans. While genetic engineering is most widely applied in agriculture, there is much speculation about how this field may benefit or enhance humans. What these studies remind us is that we still need to factor in the influence of evolution.

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