A considerable amount of recent psychological research has attributed a variety of menstrual-cycle-related changes in social behavior to evolutionarily adaptive functions. Although these studies often draw interesting and unusual conclusions about female emotion and behavior within evolutionary theory, their significant limitations have not yet been addressed. In this article, we outline several methodological and conceptual issues related to the menstrual cycle that constitute threats to the internal validity and theoretical integrity of these studies. We recommend specific guidelines to address these issues and emphasize the need to apply more comprehensive and sophisticated theoretical structures when considering menstrual-cycle-related changes in emotion and behavior.
Keywords: affect; emotion; evolutionary psychology; gender; individual differences; sex.