Sex differences in cognitive performance, style and domain relationships in mosquitofish (Gambusia affinis)

Abstract

Given that the sexes often differ in their ecological and sexual selection pressures, sex differences in cognitive properties are likely. While research on sexually dimorphic cognitionoften focuses on performance, it commonly overlooks how sexes diverge across multiple cognitive tasks (cognitive domains) and in behaviors associated with cognitive performance (cognitive style). We tested male and female western mosquitofish (Gambusia affinis) in three cognitive tasks: associative learning (numerical discrimination), cognitive flexibility (detour task), and spatio-temporal learning (shuttlebox). We characterized statistical relationships between cognitive performances and cognitive style during the associative learning task with measures of anxiety, boldness, exploration, reaction time, and activity. We found sex differences in performance, cognitive style, and the relationships between cognitive domains. Females outperformed males in spatio-temporal learning task, while the sexes performed equally in associate learning and cognitive flexibility assays. Females (but not males) exhibited a fast-exploratory cognitive style during associative learning trials. Meanwhile, only males showed a significant positive relationship between domains (associative learning and cognitive flexibility). We propose that these sexually dimorphic cognitive traits result from strong sexual conflict in this taxon; and emphasize the need to explore suites of sex-specific cognitive traits and broader comparative work examining sexual selection and cognition. HighlightsO_LIMales and females perform at similar levels in associative learning and cognitive flexibility assays, but females tend to outperform males on a spatio-temporal learning task. C_LIO_LIFemale performance in associative learning trials (numerical discrimination task) can be predicted by cognitive style behaviors (exploration, reaction time, and activity); whereas male performance cannot. C_LIO_LIMales, but not females, show a predictive relationship between associative learning and cognitive flexibility performance. C_LIO_LIOur results demonstrate that sex differences in cognition extend beyond performance into cognitive style and domain relationships, suggesting that investigations into animal personality and cognition require more comprehensive characterization. C_LI