DOI: 10.5061/dryad.hx3ffbgn5
title: Data from: Social complexity affects cognitive abilities but not brain structure in a Poecilid fish

description: 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, 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.
description: # 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. For questions or to notify
 the authors of any errors, please contact the corresponding author at:
 [zegni.triki@gmail.com](mailto:zegni.triki@gmail.com)
 \############################# # baseline\_brain.csv
 \############################# 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 standard length in mm telencephalon -------------
 telencephalon volume (mm3) mesencephalon ------------- mesencephalon
 volume (mm3) cerebellum ------------- cerebellum volume (mm3) diencephalon
 ------------- diencephalon volume (mm3) brain_stem ------------- brain
 stem volume (mm3) brain_total ------------- total brain volume (mm3)
 \############################# # data\_performance\_brain.csv
 \############################# 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)
 colour-------------- colour of the rewarding pipette in the associative
 and reversal learning tasks (red vs yellow) associative -----------
 associative score: number of test rounds for a fish to reach the learning
 criterion associative_outcome --------- outcome of the associative
 learning test: success or failure if the fish is being tested in the max
 test round without learning the association colour-reward associative_rank
 ----------- performance rank of the associative learning performance where
 higher ranks refer to higher performance associative_figure ------ used to
 generate the dot plot in Fig. 2, where failed individuals can be
 identified. reversal----------- reversal score: number of test rounds for
 a fish to reach the reversal criterion reversal_outcome -----------
 outcome of the reversal learning test: success or failure if the fish is
 being tested in the max test round without learning the reversed
 association colour-reward reversal_rank----------- performance rank of the
 reversal learning performance where higher ranks refer to higher
 performance reversal_figure ------ used to generate the dot plot in Fig.
 2, where failed individuals can be identified. prop_correct_detour -----
 the proportion of detouring correctly around the transparent cylinder
 without touching it detour_rank-------------performance rank of the detour
 test performance where higher ranks refer to higher performance
 count_correct_detour ----------- overall number of trials where the fish
 detoured correctly trial_count_detour ------------- number of trials a
 fish participated in the detour test length_mm---------- fish standard
 length in mm telencephalon ------------- telencephalon volume (mm3)
 mesencephalon ------------- mesencephalon volume (mm3) cerebellum
 ------------- cerebellum volume (mm3) diencephalon -------------
 diencephalon volume (mm3) brain_stem ------------- brain stem volume (mm3)
 brain_total ------------- total brain volume (mm3)
 \############################# # behaviour.csv
 \############################# summary data table column headings:
 tank_ID------------- the tank identity from which the fish was sampled
 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 feeding --------- data collected before and immediately
 after feeding video_duration_seconds --------- the duration in seconds of
 the video recordings aggression_guppy ------------ total number of
 aggressive bouts occurring towards a guppy aggresion_tetra --------------
 total number of aggressive bouts occurring towards splashing tetras
 aggr_guppy ------------------- aggression rate per 1sec of interaction
 calculated by dividing "aggression_guppy" by
 "video_duration_seconds" aggr_tetra -------------------
 aggression rate per 1sec of interaction calculated by dividing
 "aggresion_tetra" by "video_duration_seconds"
 nbr_images -------------------- number of snapshots collected by video
 recording guppy_guppy ------------------ distance (in cm) among guppies
 calculated from the images nbr_guppy --------------------- number of
 guppies visible on the snapshot and used to calculate
 "guppy_guppy" all -------------------------- distance (in cm)
 among all fishes (guppies and splashing tetras when present) calculated
 from the images nbr_all --------------------- number of fishes visible on
 the snapshot and used to calculate "all" missing data code: NA