Effects of the early social environment on behavioural flexibility in a cooperatively breeding cichlid fish

The ability to adapt behaviour flexibly to the current situation, also referred to as ‘behavioural flexibility’, is crucial for survival and reproductive success. The early social environment is an important driver of variation in cognitive abilities including behavioural flexibility. However, few studies have investigated this relationship across contexts. Likewise, few studies have investigated the development of modular versus general cognition (i.e. inconsistent versus consistent performance across social and nonsocial contexts) in social species. Here, (1) we investigated the influence of the early social environment (rearing group size) on behavioural flexibility in adult helpers of a cooperatively breeding cichlid fish (Neolamprologus pulcher) and (2) we assessed the presence of general or modular cognition irrespective of early experience by using three nonsocial flexibility tests (innovation test, reversal learning, set shifting) and two social flexibility tests (hierarchy test, integration test). Overall, early social experience only influenced social but not nonsocial flexibility. Helpers raised in large social groups were less flexible in the hierarchy test but tended to be accepted more often when integrated with an unfamiliar breeding pair, compared to fish raised in small groups. The early social environment did not affect nonsocial flexibility, although fish were able to adjust behaviour flexibly in both social and nonsocial contexts. For all fish, performances were not correlated across tests, implying the existence of domain-specific cognition. Nevertheless, results of a principal component analysis suggest an association between performances in social and nonsocial contexts, which may hint at domain-general cognition, albeit with the caveat that not all tests were associated with the same principal component. Future research should develop approaches that can clearly distinguish between general and modular cognition, and that compare species with different environmental predictability.