Testing the greater male variability hypothesis: male mountain chickadees exhibit larger variation in reversal learning compared to females

The ‘greater male variability hypothesis’ predicts that males exhibit larger ranges of variation in cognitive performance compared to females, however, support for this hypothesis has come exclusively from studies of humans. This scenario aligns with the fact that the vast majority of the literature assessing sex differences in cognition is based on studies of humans and a few other mammals. In order to elucidate the underpinnings of cognitive variation and the potential for fitness consequences, we must investigate sex differences in cognition in non-mammalian systems as well. Here we assess the performance of male and female food-caching birds on a spatial learning and memory task and a reversal spatial task to address whether there are sex differences in mean cognitive performance or in the range of variation in performance. For both tasks, male and female mean performance was similar across four years of testing; however, males did exhibit a wider range of variation in performance on the reversal spatial task compared to females. The implications for mate choice and sexual selection of cognitive abilities are discussed, with a call for further investigation into sex-related cognitive variation.

“男性更大变异性假说”（greater male variability hypothesis）提出，男性在认知表现上的变异范围较女性更广，但目前该假说的支持证据仅来自人类研究。这一情况与当前学界现状相符：绝大多数探讨认知性别差异的文献均基于人类及少数其他哺乳动物的研究。为阐明认知变异的基础机制及其潜在的适合度影响，我们同样需要对非哺乳类系统中的认知性别差异展开研究。本研究通过空间学习记忆任务与反转空间任务，对雌雄储食鸟类的表现进行评估，以探究认知表现的均值是否存在性别差异，抑或仅表现为变异范围的不同。在四年的测试周期内，两项任务中雌雄个体的认知表现均值均无显著差异；但在反转空间任务中，雄性个体的表现变异范围显著宽于雌性。本研究探讨了认知能力对配偶选择与性选择的潜在影响，并呼吁学界进一步开展与性别相关的认知变异研究。