Multivariate Mate Choice Constrains Mate Preference Evolution

Mate preferences are ideals or standards believed to guide our mate choices, which are crucial to an individual’s inclusive fitness. In evolutionary psychology, many specific mate preferences are theorised to have evolved because choosing a partner with the preferred trait offers inclusive fitness benefits. This evolutionary logic assumes that individuals will mate with partners whose traits align with their preferences. However, speed-dating studies often fail to find an association between preferences and actual mate choices, and recent theoretical work suggests that the more preferences are used to evaluate potential partners, the weaker this association becomes. These findings raise questions about the conventional view that the large number of observed human mate preferences could have evolved independently and simultaneously. Here, we built a computational agent-based model that simulates the evolution of ten traits via natural selection and the resulting evolution of up to ten preferences via indirect sexual selection, varying the number of preferences from one to ten. Initially, in models with fewer preferences influencing mate choice, preferences evolved visibly alongside preferred traits. However, the more preferences influenced mate choice, the slower the rate of evolution of preferences. By the ten-preference model, we observed negligible evolution of the preferences compared to robust evolution of the preferred traits. Given the numerous mate preferences observed in humans, our findings highlight the need for new explanations of how these preferences evolved.