Causation in the Nature-Nurture Debate: The Case of Genotype-Environment Interaction
I attempt to resolve an aspect of the nature-nurture debate. Consider a typical nature-nurture question: Why do some individuals develop a complex trait such as depression, while others do not? This question incorporates an etiological query about the causal mechanisms responsible for the individual development of depression; it also incorporates an etiological query about the causes of variation responsible for individual differences in the occurrence of depression. Scientists in the developmental research tradition of biology investigate the former; scientists in the biometric research tradition of biology investigate the latter. So what is the relationship?
The developmental and biometric research traditions, I argue, are united in their joint effort to elucidate what I call difference mechanisms. Difference mechanisms are regular causal mechanisms made up of difference-making variables that take different values in the natural world. On this model, individual differences are the effect of difference-makers in development that take different values in the natural world.
I apply this model to the case of genotype-environment interaction (or G×E), showing that there have actually been two separate concepts of G×E: a biometric concept (or G×EB) and a developmental concept (or G×ED). These concepts also may be integrated via the difference mechanisms model: G×E results from the interdependence of difference-makers in development that take different values in the natural world.
Advisor:Paul E. Griffiths; Sandra Mitchell; Kenneth Schaffner; Michael Pogue-Geile; Robert Olby
School:University of Pittsburgh
School Location:USA - Pennsylvania
Source Type:Master's Thesis
Keywords:history and philosophy of science
Date of Publication:09/20/2007