One consequence of the recent expansion of human genetic variability is that a number of culturally relevant SNPs are also local and cross-culturally variable in frequencies. For example, long (e.g., 7-repeat) allelic versions of dopamine receptor gene 4 (DRD4) have been linked to attention deficit hyperactivity disorder and novelty seeking. Importantly, these versions of the gene are quite common among Caucasian Americans, but they are virtually absent among Asians. Chen et al. (1999) hypothesize that long allelic versions of DRD4 provide a selective advantage in new, challenging environments because they are increasingly predominant as a function of the distance by which different ethnic groups immigrated in historic and evolutionary times (for alternative possibilities, see Cochran & Harpending 2009). Findings such as these strongly suggest that to fully understand the origins of cultural differences in psychological processes, genetic processes must be taken into account.Years ago, John Ratey and I argued in Shadow Syndromes that Americans had a higher genetic propensity to have attention deficit hyperactivity disorder, and we were right.
Shinobu Kitayama1 and Ayse K. Uskul. Culture, Mind, and the Brain: Current Evidence and Future Directions. Annu. Rev. Psychol. 2011. 62:419–49.Chen C, Burton M, Greenberger E, Dmitrieva J. 1999. Population migration and the variation of dopamine D4 receptor (DRD4) allele frequencies around the globe. Evol. Hum. Behav. 20:309–24.
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