Genes, Environment, Depression, and the Free Will Squabble


This week's post at Mind Matters, the Scientific American blog I edit, looks at an intriguing study of gene-environment interactions in abused children. Charles Glatt, who wrote the review, outlines the rather encouraging results of this study, which suggest -- with all the usual caveats about wider applicability and replication of results -- that some reliable nurturing can often override even a triple-whammy of two "bad" genes and an abusive home.

Some readers objected, however, to Glatt's assertion that the study argues well for the idea of free will. One reader wrote:

I see no impact on any discussion of free will in these findings. Are you saying that people who are abused can choose not to be depressed? I don't think that's what you mean.

I see the point of the complaint -- and I don't think that's what Glatt meant. I believe Glatt's broader point is that to the extent that the idea of free will is incompatible with the idea that genes trump experience, the strong and encouraging role that nurturing played in the study he reviewed argues in favor of free will. That argument is strengthened, if in roundabout fashion, if you recognize that gene-environment effects don't merely flick genes on and off but also create a dynamic in which the changing person (changed, i.e., by genetic response to environment) may change in a way that better enables him or her to behave differently, thus changing the environment. A nurturing presence gives me some resilience, increasing my ability to behave constructively.

It gets a bit slippery. Ideed, it starts to erase the fate v. free-will distinction, just as the looping quality of gene-environment interactions (in which environment affects gene expression, which changes behavior, including the ability to change the environment, which in turn affects gene expression) makes moot the either-or choice between nature and nurture. In the end, each is eternally modified by the other, and thus parent and offspring of the other, not terribly unlike an Escher drawing.

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