Displaying Altruism as a Sexual Signal in Human Mate Choice is an Adaptation – An Interdisciplinary Overview of the Evidence

Numerous studies in humans have shown that altruism may influence mate choice decisions, highlighting its potential role as a sexual signal. Whether using altruism as a signal is an adaptation, however, remains largely unresolved. In this review, we aim to investigate the adaptive nature of altruism as a sexual signal by constructing a comprehensive nomological network of evidence. Drawing upon interdisciplinary scientific modes of evidence (psychology, medicine, physiology, genetics, phylogenetics, hunter-gatherer studies, cross-cultural studies, and theoretical studies), our analysis reveals an extensive breadth of evidence across the various disciplines supporting the hypothesis that altruism is an adaptive sexual signal. However, only the psychological evidence demonstrates substantial depth. Other fields exhibit a lack of variation in research methods or a minimal amount of studies, limiting the strength of their respective contributions. Despite these limitations, there is still sufficient support for the nomological network. Based on the evidence of the various disciplines, we conclude that there is sufficient support that altruism as a sexual signal is an adaptation. We provide considerations for future research that would expand the scope of the evidentiary depth across the various disciplines, which would strengthen our understanding of the role of sexual selection in human altruism.