No Evidence for a Relationship between Intelligence and Ejaculate Quality

The sexual selection of creativity: A nomological approach

Cultural innovations, such as tools and other technical articles useful for survival, imply that creativity is an outcome of evolution. However, the existence of purely ornamental items obfuscates the functional value of creativity. What is the functional or adaptive value of aesthetic and intellectual ornaments? Recent evidence shows a connection between ornamental creativity, an individual's attractiveness, and their reproductive success. However, this association is not sufficient for establishing that creativity in humans evolved by sexual selection. In this critical review, we synthesize findings from many disciplines about the mechanisms, ontogeny, phylogeny, and the function of creativity in sexual selection. Existing research indicates that creativity has the characteristics expected of a trait evolved by sexual selection: genetic basis, sexual dimorphism, wider variety in males, influence of sex hormones, dysfunctional expressions, an advantage in mating in humans and other animals, and psychological modules adapted to mating contexts. Future studies should investigate mixed findings in the existing literature, such as creativity not being found particularly attractive in a non-WEIRD society. Moreover, we identified remaining knowledge gaps and recommend that further research should be undertaken in the following areas: sexual and reproductive correlates of creativity in non-WEIRD societies, relationship between androgens, development, and creative expression, as well as the impact of ornamental, technical and everyday creativity on attractiveness. Evolutionary research should analyze whether being an evolved signal of genetic quality is the only way in which creativity becomes sexually selected and therefore passed on from generation to generation. This review has gone a long way toward integrating and enhancing our understanding of ornamental creativity as a possible sexual selected psychological trait.

Mate Retention Behavior and Ejaculate Quality in Humans

Males of some species use mate retention behavior and investment in ejaculate quality as anti-cuckoldry tactics concurrently while others do so in a compensatory fashion. Leivers, Rhodes, and Simmons (2014) reported that men who performed mate retention less frequently produced higher-quality ejaculates, suggesting that humans use these tactics compensatorily. We conducted a conceptual replication of this research in a sample of 41 men (18-33 years; M = 23.33; SD = 3.60). By self-report, participants had not had a vasectomy and had never sought infertility treatment. We controlled for several covariates known to affect ejaculate quality (e.g., abstinence duration before providing an ejaculate) and found no statistically significant relationships between mate retention behavior and four components of ejaculate quality: sperm velocity, sperm concentration, slow motility, and ejaculate volume. The present results provide little support for the hypothesis that human males deploy mate retention behavior and ejaculate quality investment compensatorily. We discuss the limitations of this study and highlight the need for research to address questions about the nature of anti-cuckoldry tactic deployment in humans, especially concerning investment in ejaculate quality.