Triki Zegni, Zhou Tunhe, Argyriou Elli, Sousa de Novais Edson, Servant Oriane, Kolm Niclas
Behavioral Ecology Division, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland.
Department of Zoology, Stockholm University, Svante Arrheniusväg 18 B, 10691, Stockholm, Sweden.
Behav Ecol. 2024 Apr 2;35(3):arae026. doi: 10.1093/beheco/arae026. eCollection 2024 May-Jun.
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 (). 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 ()-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.
一些认知能力被认为是复杂社会生活的结果，这使个体能够通过先进策略实现更高的适应性。然而，大多数证据都是相关性的。在这里，我们对群体大小和组成如何影响孔雀鱼的大脑和认知发展进行了实验研究。在6个月的时间里，我们将性成熟的雌性孔雀鱼饲养在三种社会处理方式之一中：一个由3条孔雀鱼组成的小同物种群体、一个由3条孔雀鱼和3条溅水鱼（一种在野外与孔雀鱼共生的物种）组成的大异物种群体，以及一个由6条孔雀鱼组成的大同物种群体。然后，我们测试了孔雀鱼在自我控制（抑制控制）、操作性条件反射（联想学习）和认知灵活性（逆向学习）任务中的表现。通过X射线成像，我们测量了它们的大脑大小和主要脑区。由6个个体组成的较大群体，无论是同物种群体还是异物种群体，在认知灵活性方面都比小群体表现更好，但在自我控制和操作性条件反射测试中没有差异。有趣的是，虽然社会操纵对大脑形态没有显著影响，但相对较大的端脑与更好的认知灵活性相关。这表明，除了脑区大小之外，还有其他机制使来自较大群体的个体具有更高的认知灵活性。虽然没有明确证据表明对大脑形态有影响，但我们的研究表明，生活在较大的社会群体中可以提高认知灵活性。这表明社会环境在孔雀鱼的认知发展中发挥了作用。
