Individual Differences in Executive Functions Are Almost Entirely Genetic in
Naomi Friedman, Akira Miyake, Susan Young, John DeFries, Robin Corley & John
Journal of Experimental Psychology: General, May 2008, Pages 201-225
Recent psychological and neuropsychological research suggests that executive functions-the cognitive control processes that regulate thought and action-are multifaceted and that different types of executive functions are correlated but separable. The present multivariate twin study of 3 executive functions (inhibiting dominant responses, updating working memory representations, and shifting between task sets), measured as latent variables, examined why people vary in these executive control abilities and why these abilities are correlated but separable from a behavioral genetic perspective. Results indicated that executive functions are correlated because they are influenced by a highly heritable (99%) common factor that goes beyond general intelligence or perceptual speed, and they are separable because of additional genetic influences unique to particular executive functions. This combination of general and specific genetic influences places executive functions among the most heritable psychological traits. These results highlight the potential of genetic approaches for uncovering the biological underpinnings of executive functions and suggest a need for examining multiple types of executive functions to distinguish different levels of genetic influences.
Two Genes Predict Voter Turnout
James Fowler & Christopher Dawes
Journal of Politics, July 2008, Pages 579-594
Fowler, Baker, and Dawes (2008) recently showed in two independent studies of twins that voter turnout has very high heritability. Here we investigate two specific genes that may contribute to variation in voting behavior. Using data from the National Longitudinal Study of Adolescent Health, we show that individuals with a polymorphism of the MAOA gene are significantly more likely to have voted in the 2004 presidential election. We also find evidence that an association between a polymorphism of the 5HTT gene and voter turnout is moderated by religious attendance. These are the first
results ever to link specific genes to political behavior.
(Nod to KL)