Are Sex Differences in Human Brain Structure Associated With Sex Differences in Behavior?

• Published in: Psychological science Vol. 32; no. 8; pp. 1183 - 1197
• Main Authors: van Eijk, Liza, Zhu, Dajiang, Couvy-Duchesne, Baptiste, Strike, Lachlan T., Lee, Anthony J., Hansell, Narelle K., Thompson, Paul M., de Zubicaray, Greig I., McMahon, Katie L., Wright, Margaret J., Zietsch, Brendan P.
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.08.2021; SAGE PUBLICATIONS, INC; Association for Psychological Science
• Subjects: Behavior; Brain; Brain - diagnostic imaging; Brain size; Brain structure; Causality; Connectome; Cultural differences; Female; Gender differences; Humans; Individual differences; Life Sciences; Magnetic Resonance Imaging; Male; Psychological Science in the Public Eye; Sex Characteristics; Sex differences; Twins; Women; open data; MRI; brain structure; masculinization; twin modeling; neuroimaging
• ISSN: 0956-7976; 1467-9280; 1467-9280
• DOI: 10.1177/0956797621996664

On average, men and women differ in brain structure and behavior, raising the possibility of a link between sex differences in brain and behavior. But women and men are also subject to different societal and cultural norms. We navigated this challenge by investigating variability of sex-differentiated brain structure within each sex. Using data from the Queensland Twin IMaging study (n = 1,040) and Human Connectome Project (n = 1,113), we obtained data-driven measures of individual differences along a male–female dimension for brain and behavior based on average sex differences in brain structure and behavior, respectively. We found a weak association between these brain and behavioral differences, driven by brain size. These brain and behavioral differences were moderately heritable. Our findings suggest that behavioral sex differences are, to some extent, related to sex differences in brain structure but that this is mainly driven by differences in brain size, and causality should be interpreted cautiously.