Social complexity affects cognitive abilities but not brain structure in a Poecilid fish

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 six months, we reared sexually mature females in one of three social treatments: a small conspecific group of three guppies, a large heterospecific group of three guppies and three splash tetras (Copella arnoldi) – a species that co-occurs with the guppy in the wild, and a large conspecific group of six 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 six individuals, both conspecific and heterospecific groups, s..., , , # Social complexity affects cognitive abilities but not brain structure in a Poecilid fish

Please refer to the manuscript for context, data collection methods and statistical analyses.

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# baseline\_brain.csv

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summary data table

column headings:

fish_ID -------- fish identity

treatment----------- the social treatment: group of three guppies as small conspecific group, group of three guppies with three splash tetras as large heterospecific group, and a group of six guppies as large conspecific group

category------------ the category of these samples, which is baseline dataset

tank_ID------------- the tank identity from which the fish was sampled

batch---------------- the number of batch from which the fish was sampled (batch 01 or batch 02)

length_mm---------- fish st...