The influence of social rank on learning in a group-living fish

Dominance hierarchies are found in many group-living species, and an individual's social rank can influence their access to resources, behaviours and physiology. However, the effect of rank on learning capability has not been well studied. Here, we examined how rank influences learning in the group-living cichlid fish Neolamprologus pulcher. We tested learning in both dominant and subordinate fish and investigated whether rank is related to the capacity to learn independently as well as from others. Fish learned to move coloured discs to access a food reward, either by trial and error on their own, or by watching a trained demonstrator. We found no differences between ranks in the individual associative learning task, but subordinates were faster at changing their behaviour when we changed the reward rules (during the reversal learning phase). We also found no differences in the number of trials it took dominants and subordinates to socially learn the task (from watching demonstrators), but individuals learned the task faster when they could observe others. Our results indicate that some aspects of cognition can be influenced by social rank, but rank does not appear to affect general learning ability.