FINISHED PROJECTS USING AN EVOLUTIONARY PERSPECTIVE:
Van den Akker, O. R., Van Assen, M. A. L. M., Van Vugt, M., & Wicherts, J. M. (under review). Sex differences in trust and trustworthiness: A meta-analysis of the trust game and gift-exchange game
The meta-analyses for the trust game included 174 effect sizes from 77 papers and 17,082 participants from 23 countries, while the meta-analyses for the gift-exchange game included 35 effect sizes from 15 papers and 1,362 participants from 19 countries. We found that men send more in the trust game and in the gift-exchange game only if their transfers in those games cause an efficiency gain. We label this finding the “male multiplier effect”.
Cronk, L., Steklis, H. D, Steklis, N., Van den Akker, O. R., & Aktipis, A. (2019). Kinship and fitness interdependence.
In this theoretical paper, we try to explain why people use kinship terms, even in situation where they are not genetically related. We believe that kinship terms not only come about through situations of genetic interdependence, but through situations of fitness interdependence in general - situations where someone’s fitness depends on the behavior of another.