Personality evolution

“The author argues that each of the Big Five dimensions of human personality can be seen as the result of a trade-off between different fitness costs and benefits. As there is no unconditionally optimal value of these trade-offs, it is to be expected that genetic diversity will be retained in the population.” in Nettle, D. ‘The Evolution of Personality Variation in Humans and Other Animals.’ American Psychologist. 61(6), Sep 2006, 622-631.