The study examined how the interplay between children's cortisol response and family income is related to executive function (EF) skills. The sample included one hundred and two 5- to 6-year-olds (64% minority). EF skills were measured using laboratory tasks and observer ratings. Physiological reactivity was assessed via cortisol response during a laboratory visit. A consistent, positive association between family income and EF skills emerged only for children who showed high cortisol response, a marker of biological sensitivity to context. In contrast, family income was not related to EF skills in children who displayed low cortisol response. Follow-up analyses revealed a disordinal interaction, suggesting that differential susceptibility can be detected at the level of basic cognitive and self-regulatory skills that support adaptive functioning.
© 2015 The Authors. Child Development © 2015 Society for Research in Child Development, Inc.