Robust Evidence for Moderation of Ovulatory Shifts by Partner Attractiveness in Arslan et al.'s (2020) Data

Arslan et al. (2020) conducted a large-scale, preregistered daily diary study on over 400 normally ovulating women. Of core interest were hypotheses that women's ratings of their partner's sexual attractiveness moderate associations of fertility status with women's own extrapair sexual desires, their own interest in in-pair sex, and their partners' mate retention tactics. The authors claim that "no evidence for moderator effects" (p. 426) was found. In fact, their own analyses reported in their supplementary material show robust evidence for moderation effects. Moreover, a new reanalysis using a more comprehensive composite measure of male partner sexual attractiveness yielded even stronger results. Effect size estimates are consistent with the existence of large, meaningful moderation effects, revealing that this study actually does show evidence of moderation effects. Additional analyses show similarly strong moderator effects on male proprietariness. We discuss the findings in the context of reliance on binary (significant vs. nonsignificant) labels and the pitfalls of underreporting effects.