Continuous contributions of the dorsolateral striatum to movement initiation and execution.

Gender differences in personality traits have long been a central topic in personality psychology. Although broad consensus exists that men and women differ on certain personality dimensions, the magnitude, structure, and interpretation of these differences remain debated [,]. Competing accounts attribute observed differences to sociocultural influences, biological factors, or their interaction [,]. Clarifying how gender differences are quantified and interpreted therefore remains of fundamental importance. Traditionally, gender differences in personality have been summarized using univariate effect sizes, most commonly Cohen’s [] – some meta-analytic reviews have emphasized that many observed differences are small in magnitude [,]. Within standardized personality frameworks such as the Five-Factor Model (Big5) [], consistent differences have been reported for traits such as Neuroticism and Agreeableness [,,]. In the Sixteen Personality Factor Model (16PF), somewhat larger differences have been observed for traits including Sensitivity, Anxiety, and Warmth []. However, univariate effect sizes quantify marginal mean differences and do not account for correlations among traits. To address this limitation, Del Giudice and colleagues proposed the Mahalanobis distance () as a multivariate measure of gender differentiation that incorporates covariance structure [,]. Under this framework, relatively modest univariate effects have been shown to correspond to substantially larger multivariate separation [,–]. Subsequent methodological work has emphasized that multivariate effect sizes capture not only mean differences but also covariance structure among traits, and that trait intercorrelations can substantially reshape interpretations of group differentiation [,]. These findings suggest that the interpretation of gender differences in some cases depends critically on multivariate trait structure rather than on marginal effects alone.