The Tell-Tale Hand

Abstract

Abstract. The second-to-fourth digit ratio (2D:4D), an inconspicuous, but sexually differentiated anatomical trait (men present lower 2D:4D than women), has received intense research interest recently. Fairly strong evidence points to 2D:4D as a biomarker for the organizational (permanent) effects of prenatal testosterone on the brain and behavior. 2D:4D has been shown to be a correlate of a wealth of sex-dependent, hormonally influenced traits and phenotypes, which reach into the domains of behavior, fertility, health, physique, sexuality, and sports and also deeply into differential psychology (ability, cognition, and personality). This study investigated whether individual differences in 2D:4D are related to individual differences in attractiveness, sex typicality, and other attributes ascribed to palm images by raters. For both sexes, more sex-atypical trait expressions (i.e., higher 2D:4D in male, but lower 2D:4D in female palm specimens) were related to higher aggregate ratings of attractiveness, healthiness, sexiness, imagined handshake pleasantness, and imagined person dominance, albeit only the last association achieved formal statistical significance with two-tailed testing. These findings suggest that 2D:4D might be a correlate of perceived dominance and possibly also of other attributes. Digit ratio associations with sex-typicality ratings (sex-of-hand judgments and perceived palm masculinity and femininity) were inconsistent and mostly of smaller size. Finger lengths (2D and 4D) were generally more strongly and consistently related to palm attributes than 2D:4D was. Implications of the findings, study limitations, and directions for future research are considered.