Mate choice copying in humans: a systematic review and meta-analysis

Objective: Mate choice copying (MCC) is a type of non-independent mate choice where the ‘probability of acceptance’ of a potential mate increases if they are observed to be chosen by others first. The phenomenon was first demonstrated in several non-human taxa, with studies on humans conducted shortly after. The effect has been consistently documented among women choosing men (female choice), with mixed results among men choosing women (male choice). To understand and test the overall level of support for MCC in humans, we conducted a systematic review and meta-analysis, including a sensitivity analysis for publication bias. Methods: We found that the two most commonly used methods of studying MCC in humans involved either the ‘addition’ of a cue (opposite sex other) or the ‘augmentation’ of cues (manipulating ‘mate quality’ of opposite sex other). We performed separate meta-analyses for these two approaches, splitting each into male choice and female choice. Results: Women were more likely to rate male targets as more desirable when presented alongside a female while no obvious effects were detected with male choice. These sex differences disappeared in studies that ‘augment’ cues, as both sexes rated targets as more attractive when in the presence of more desirable others. We also detected high levels of heterogeneity in effect sizes and a moderate publication bias in favor of positive reports of MCC. Conclusions: Our results provide clarification for documented sex differences (or lack thereof) in human MCC. We also discuss the importance of method consistency in studies that transfer ideas from non-human to human behavioral studies, highlighting replication issues in the light of the publication crisis in psychological science