meta-analysis of twin and family studies produced a pooled heritability estimate of approximately .60 (van Beijsterveldt & van Baal, 2002), and heritability appears to change little through middle adulthood (Smit, Posthuma, Boomsma, & de Geus, 2007). At least two studies have reported that P300 amplitude is less heritable among female adolescents than among males (van Beijsterveldt, et al., 2001; Yoon, et al., 2006), suggesting that P300 amplitude's role as an endophenotype may be sex-specific.
