Exploring the evolved concept of NEWCOMER: experimental tests of a cognitive model.

Enduring human coalitions face the adaptive problem of integrating new members. Although newcomers can provide benefits (e.g., additional labor), newcomers can also create costs (e.g., by free riding). Due to the unique adaptive problems they pose, we hypothesize that the mind contains an evolved concept of NEWCOMER. We test the design of this concept experimentally and show that the activation of the NEWCOMER concept elicits a variety of anti-free rider responses (e.g., a decrease in trust) with adaptively-targeted exceptions (e.g., a minimal increase in exclusion sentiment). These results support the hypothesis that the mind contains specialized concepts for understanding, creating, and sustaining intergenerational coalitions.