Razib Khan One-stop-shopping for all of my content

November 11, 2011

Personality and genes

Filed under: Behavior Genetics,Genes,Personality — Razib Khan @ 6:10 am

There’s a variable in the GSS, GENEEXPS, which asks if genes play a role in personality. The options are:

- It’s genes which play a major role

- It’s experience which determines personality

First, let’s admit that the premise is stupid. Personality is heritable, but environmental variation also seems to matter. In other words it is noncontroversial to assert that both genes and environment can explain variation in personality (or perhaps more precisely genetic variation can only explain around half the variation for any given trait).

I was curious how this broke down by education and intelligence. To remove demographic confounds I limited the sample to non-Hispanic whites. For intelligence I used WORDSUM, with scores 0-4 being dumb, 5-7 being average, and 8-10 being smart.

Genes play major role Experience plays major role
Less than HS 33 67
High School 26 74
Junior College 26 75
Bachelor 21 79
Graduate 24 77
Dumb 25 75
Average 25 75
Smart 24 76

May 6, 2011

How the “fierce people” came to be

The pith: there are differences between populations on genes which result in “novelty seeking.” These differences can be traced to migration out of Africa, and can’t be explained as an artifact of random genetic drift.

I’m not going to lie, when I first saw the headline “Out of Africa migration selected novelty-seeking genes”, I was a little worried. My immediate assumption was that a new paper on correlations between dopamine receptor genes, behavior genetics, and geographical variation had some out. I was right! But my worry was motivated by the fact that this would just be another in a long line of research which pushed the same result without adding anything new to the body of evidence. Let me be clear: there are decades of very robust evidence that much of the variation in human behavior we see around us is heritable. That the variation in our psychological dispositions, from intelligence to schizophrenia, is substantially explained by who our biological parents are. This is clear when you look at adoption studies which show a strong concordance between biological parents and biological children on many metrics as adults, as opposed ...

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