Extragroup interactions are not related to cognitive performance in a group-living passerine

Abstract

Sociality, in particular group-living, can present many challenges to individuals and is widely thought to influence the development and evolution of cognition. However, support for the effect of sociality on cognition is mixed, and it has recently been suggested that an entire axis of sociality has been overlooked—extragroup interactions. Extragroup interactions (those that occur with a heterospecific or conspecific individual outside of the focal individual's group) present informational challenges that may favour certain cognitive phenotypes, such as discrimination, assessment and categorization. We quantified the rates of two types of extragroup interactions (intergroup and interspecific interactions) in adult Western Australian magpies (Gymnorhina tibicen dorsalis) and compared these to individual performance across a battery of four cognitive tasks. We also investigated whether response to playback of intruding conspecifics (an assessment of quantity discrimination abilities) was related to intergroup interaction rate. We hypothesized that greater involvement in extragroup interactions would be positively related to cognitive performance; however, we found no support for this. We did identify a relationship between intergroup interaction rate and response to playback, with individuals involved in more intergroup interactions exhibiting a greater difference in response to one and three calling extragroup conspecifics. Our findings suggest that extragroup interactions experienced in adult life do not influence performance in food-based cognitive tasks, but research on individuals during the developmental stage is needed to rule out an effect of extragroup interactions on cognitive development.