【2019-06-12】 有研究显示，大五人格中的外向性（extraversion）和祖先的迁移经历有关，越是在晚近历史中经历过迁移的，越可能偏于外向，游牧民族比定居民族更外向，这一点好像和一般大众印象吻合，美国人就比较外向，而中西部比东北更外向，新英格兰最内向，中国各省中，据说四川人和东北人都比较外向，这一流行刻板印象或许是对的。 有关研究见David M. Buss & Patricia H. Hawley (2011) ch.1----

Interestingly, Chen, Burton, Greenberger, & Dmitrieva (1999) showed that ‘long’ alleles of the D4DR gene in humans are more common in populations that are nomadic or have historically completed long migrations than in populations that have been sedentary for a long time. The D4DR long alleles are also associated with personality traits and behaviors related to extraversion (Ebstein, 2006). This suggests that nomadism and social fluidity select for increasing extraversion.