Perceptions of Sex Ratios

Sex Ratios

My research focuses on the cognitive processes underlying the tracking and perception of sex ratios. One topic of interest is the cognitive bounds around sex ratio tracking. This line of research examines the sex ratio tracking process to determine how accurate people are at tracking sex ratios and how automatically they track sex ratios.

My second line of research examines if people are tracking overall sex ratio, adult sex ratio (adult males to females; ASR), or operational sex ratio (males to females that are available and viable potential mates; OSR). These distinctions are important because the ratios can be different within the same population, yet many previous studies have used only OSR because their stimuli matched the age ranges of their subjects (i.e. typically young adults).

My third line of research is examining the effect of individual differences, such as sexual orientation or daily experienced sex ratio, on the tracking of sex ratios.

Brandner, Dillon, & Brase, 2020

Brandner, J. L., Dillon, H. M., & Brase, G. L. (In Press). Convergent evidence for a theory of rapid, automatic, and accurate sex ratio tracking. Acta Psychologica.

Abstract: It is presumed that people track the sex ratios in their environment (the number of males relative to number of females) in order to adaptively adjust their decisions and behaviors, but this actual tracking ability has not been established. The relevance of sex ratio information, drawn from evolutionary biology and studies of human relationship decision making, is integrated here with memory research (on frequency encoding), perception research (on ensemble coding), and neuroscience research. A series of four experiments provide empirical results to help fill research gaps and facilitate this theoretical integration. In particular, these studies connect details from memory research on relatively automatic frequency encoding of both items and categories, perception research on summary statistics from ensemble coding, and theoretical ideas about the function of these abilities (specifically applied to human sex ratios based on faces) from social and evolutionary approaches. Collectively this research demonstrates an evolved psychological mechanism for functional, fast, and relatively automatic human abilities to track experienced sex ratios in the social world. This sex ratio information is theorized to underpin documented facultative adjustments in relationship dynamics as well as perceptions of social group characteristics. This integrative approach highlights how the coding, memory, and judgments about population sex ratios can both account for a number of existing findings and point towards key further research.

Please email me for a copy of the full-text article.

HBES 2019 Talk

HBES 2019 Brandner Talk.mp4

HBES 2019 Slides

Brandner HBES 2019 Presentation for Web.pptx