What do evolutionary models teach us about sensitive periods in psychological development?

Sensitive periods in development are widespread in nature. Many psychologists and biologists regard sensitive periods as byproducts of developmental processes. Although this view may be correct in some cases, it is unlikely to be the whole story. There is large variation in sensitive periods (a) between species in the same trait (Beecher & Brenowitz, 2005), (b) between individuals of the same species (Frankenhuis, Panchanathan, & Belsky, 2016), and (c) between different traits within a single individual (Zeanah, Gunnar, McCall, Kreppner, & Fox, 2011). In this article, we discuss recent insights provided by formal models of the evolution of sensitive periods. These models help to identify the conditions in which sensitive periods are likely to evolve, and make predictions about the factors that affect their development. We conclude by discussing future directions for empirical research.