A major component of Darwin's formulation of sexual selection theory is whether mate choice can contribute to the evolution of cognitive abilities. Although a correlation between cognition and attractive traits has commonly been reported, the processes that generate such associations remain elusive. Here, we investigated female preference, neophobia and spatial learning in the sailfin tetra, Crenuchus spilurus, a sexually dimorphic fish. Females chose the most ornamented males, which were also more neophobic. This is in line with the asset protection principle, which posits that attractive males should be more cautious because of their higher prospective fitness returns. After repeated exposure, more ornamented males learnt to navigate the complex maze faster, with chosen (and highest ornamented) males showing higher accuracy to solve the maze on the last day of trials. Because the asset protection principle stems from predation pressure, we propose that sexual selection through female mate choice creates a risk–reward trade-off, upon which natural selection acts by indirectly increasing learning abilities. As such, sexual selection forms the substrate, but natural selection drives enhanced cognitive abilities in attractive C. spilurus males.

达尔文提出的性选择理论的一个主要组成部分是伴侣的选择是否可以促进认知能力的发展。尽管通常已经报道了认知与吸引人的特征之间的相关性，但是产生这种关联的过程仍然难以捉摸。在这里，我们调查了Sailfintetra，Crenuchus spilurus中的女性偏好，新恐惧症和空间学习，是一种两性异形的鱼。女性选择了装饰最丰富的男性，它们也更具新恐惧感。这符合资产保护原则，该原则提出，有吸引力的男性应更加谨慎，因为他们的预期健康回报更高。在反复暴露之后，更多有装饰的雄性学会了更快地导航复杂的迷宫，在试验的最后一天，选择（装饰最高的）雄性显示出更高的精度来解决迷宫。因为资产保护原则源于掠夺压力，所以我们建议通过女性伴侣的选择来进行性选择会产生风险-回报的折衷，自然选择会通过间接提高学习能力来起作用。因此，性选择构成了基础，但自然选择却在吸引人方面增强了认知能力C. spilurus雄性。