Evaluating these possibilities has proved difficult. In humans, quantifying total fitness and relating it to personality traits is challenging even in contemporary societies, and it is harder still to infer relationships between total fitness and personality traits in the varied environments of our evolutionary history. However, using recently-developed methodologies in statistical genetics, it is possible to test competing predictions from the three evolutionary models. In the present investigation, we attempt to gain insight into several properties of alleles underlying human personality—their number, their effect sizes, their commonness in the population (i.e. minor allele frequency; MAF), and their degree and direction of recessiveness –to gain traction on the mechanisms most likely influencing their genetic variation (Keller et al. 2011a).
