a1 Department of Psychology, Yale University, New Haven, CT 06520-8205 firstname.lastname@example.org
a2 Department of Psychology, Arizona State University, Tempe, AZ 85287-1104. email@example.com
Evolutionary models of behavior often encounter resistance due to an apparent focus on themes of sex, selfishness, and gender differences. The target article might seem ripe for such criticism. However, life history theory suggests that these themes, and their counterparts, including cooperation, generosity, and gender similarities, represent two sides of the same coin – all are consequences of reproductive trade-offs made throughout development.