Wives became more jealous than husbands when their partner got a new platonic friend

Sucrese, A. M., Burley, E. E., Perilloux, C., Woods, S. J., & Bencal, Z. (2022). Just friends? Jealousy of extramarital friendships. Evolutionary Behavioral Sciences. Advance online publication. https://doi.org/10.1037/ebs0000296

Abstract: Past research in evolutionary psychology has proposed, and found evidence of, sex differences in the adaptive functions of jealousy. However, no research has focused specifically on the output of jealousy adaptations in the context of a spouse’s apparently platonic extramarital friendship. In the current preregistered study, we asked married individuals (N = 394 Amazon Mechanical Turk users) to read a scenario in which their spouse recently formed a new platonic friendship. We randomly assigned participants to one of four scenarios that varied the sex and attractiveness level of the friend and assessed how jealous the scenario would make participants and whether they attributed any felt jealousy to emotional or sexual concerns. In contrast to our predictions, women indicated more overall jealousy than men. Furthermore, both men and women were more likely to attribute their jealousy to sexual reasons when their spouse’s friend was the same sex as they are, representing a potential rival. We documented several other interactions related to emotional attributions of jealousy, further supporting the perspective that jealousy is nuanced and context dependent. Perhaps emotional jealousy functions as an adaptive solution to any situation that threatens diversion of a mate's resources and investment, not just diversion to a potential mate.