PDF(Pubmed)
Abstract：
Some cognitive abilities are suggested to be the result of a complex social life, allowing individuals to achieve higher fitness through advanced strategies. However, most evidence is correlative. Here, we provide an experimental investigation of how group size and composition affect brain and cognitive development in the guppy (Poecilia reticulata). For 6 months, we reared sexually mature females in one of 3 social treatments: a small conspecific group of 3 guppies, a large heterospecific group of 3 guppies and 3 splash tetras (Copella arnoldi)-a species that co-occurs with the guppy in the wild, and a large conspecific group of 6 guppies. We then tested the guppies\' performance in self-control (inhibitory control), operant conditioning (associative learning), and cognitive flexibility (reversal learning) tasks. Using X-ray imaging, we measured their brain size and major brain regions. Larger groups of 6 individuals, both conspecific and heterospecific groups, showed better cognitive flexibility than smaller groups but no difference in self-control and operant conditioning tests. Interestingly, while social manipulation had no significant effect on brain morphology, relatively larger telencephalons were associated with better cognitive flexibility. This suggests alternative mechanisms beyond brain region size enabled greater cognitive flexibility in individuals from larger groups. Although there is no clear evidence for the impact on brain morphology, our research shows that living in larger social groups can enhance cognitive flexibility. This indicates that the social environment plays a role in the cognitive development of guppies.
摘要：
一些认知能力被认为是复杂的社会生活的结果，允许个人通过先进的策略实现更高的健身。然而,大多数证据都是相关的。这里,我们提供了一项实验研究，以了解小组的大小和组成如何影响孔雀鱼（Poeciliareticulata）的大脑和认知发育。6个月,我们在3种社会治疗方法中的一种中饲养性成熟的雌性：一个由3只孔雀鱼组成的小物种组，一个由3只孔雀鱼和3只飞溅的四强（Copellaarnoldi）组成的大型异类组-与野外孔雀鱼共同出现的物种，和一大群6只孔雀鱼。然后我们测试了孔雀鱼在自我控制(抑制控制)中的表现，操作条件(联想学习)，和认知灵活性(反转学习)任务。用X射线成像,我们测量了他们的大脑大小和主要的大脑区域。6个人的较大群体，同种和异种群体，与较小组相比，显示出更好的认知灵活性，但在自我控制和操作条件测试中没有差异。有趣的是,虽然社会操纵对大脑形态没有显著影响，相对较大的端脑与较好的认知灵活性相关.这表明超出大脑区域大小的替代机制使来自更大群体的个体具有更大的认知灵活性。尽管没有明确的证据表明对大脑形态的影响，我们的研究表明，生活在更大的社会群体中可以增强认知灵活性。这表明社会环境在孔雀鱼的认知发展中起着作用。
