Evidence for a robust, estradiol-associated sex difference in narrative-writing fluency.

Objective: Despite evidence for an estradiol-linked sex difference in verbal fluency favoring women, recent reviews question this difference. We therefore examined the issue based on a narrative task that we have administered to different populations for over 20 years. Method: We meta-analyzed 98 studies (N = 11,528) conducted by our laboratories and that featured measures of biological sex and storytelling. We ran primary-data analyses (N = 797) on an overlapping subset of these studies that also included salivary hormone and digit ratio measures. Results: Women told longer stories than men, d = 0.31, 95% CI [0.24, 0.38], an effect that did not vary by geographic region but was moderated by cue type (verbal: d = 0.57, [0.44, 0.71]; pictures: d = 0.29, [0.22, 0.36]), response modality (oral: d = -0.04, [-0.18, 0.09]; handwriting: d = 0.39, [0.31, 0.47]; typing: d = 0.31, [0.21, 0.42]), and age (prepubertal children: d = 0.13, [-0.04, 0.30]; pubescents: d = 0.48, [0.23, 0.74]; premenopausal adults: d = 0.36, [0.29, 0.42]; postmenopausal adults: d = -0.09, [-0.35, 0.16]). Consistent with the age effect, estradiol, a sex-dimorphic hormone during the reproductive life stage, was a specific mediator of the sex difference in narrative-writing fluency. This mediation effect was moderated by prenatal hormone exposure, estimated via digit ratio. Conclusions: When verbal fluency is assessed through narrative writing, a robust female advantage becomes evident. It is associated with the reproductive life stage and variations in current estradiol concentrations, particularly in individuals prenatally exposed to relatively more estradiol than testosterone. (PsycInfo Database Record (c) 2020 APA, all rights reserved).