The Gender-Equality Paradox: A Longitudinal Test of the Free Expression or Resource Hypothesis Among Adolescents

The gender-equality paradox posits that gender differences tend to widen in societies characterized by greater gender equality and economic prosperity. Evolutionary psychology–based accounts, including the free expression or resource hypothesis, argue that such patterns emerge because innate differences between men and women are more fully expressed under favorable societal conditions. The present study evaluated predictions derived from the free expression/resource hypothesis using longitudinal data from U.S. adolescents. Data were drawn from five waves (1994–2018) of the National Longitudinal Study of Adolescent to Adult Health ( N = 6,504), a period during which both gender equality and GDP increased in the United States. The findings largely contradicted the core predictions of the free expression or resource hypothesis. Gender differences in mathematics and science GPA, cognitive abilities, and risk-taking showed no evidence of change over time. Furthermore, gender differences in self-esteem and depression decreased rather than increased across the study period, contrary to the hypothesis. Overall, these findings challenge the validity of the free expression or resource hypothesis as an explanation for the gender-equality paradox.