Comparative cognition between social and non-social cichlids

Abstract

Cooperation often draws on cognition (i.e. learning and memory) in order to track cooperative partners and their contributions, resolve conflict between partners, improve coordination between partners, and enhance strategic-decision making. Learning and memory are also vital to resolve what is frequently a spatial and temporal mismatch between performing a cooperative act and receiving any kind of benefit in return. In this thesis, I compared cognitive abilities between three cooperative and group-living cichlid fishes from the Lamprologini tribe of Lake Tanganyika Neolamprologus pulcher, Neolamprologus multifasciatus, and Julidochromis ornatus with three of their close relatives that are not cooperative and never form groups Telmatochromis temporalis, Altolamprologus compressiceps, and Neolamprologus tretocephalus. This thesis aims to address whether the evolution of cooperation coincided with the evolution of sophisticated cognition in these fishes. In Chapter 2, I present evidence that both cooperative and non-cooperative cichlids are able to recognize familiar individuals and have similar numerical abilities. In Chapter 3, I show that performance when learning to navigate a maze, arguably a more general cognitive ability, was equivalent across cooperative and non-cooperative species, with comparable scores in terms of time to maze completion, number of mistakes and inhibitory control. In Chapter 4, I report on the results of a literature review where I quantified the growing interest in the field of fish cognition research, outline the current practices and pitfalls (heavy use of captive bred individuals and a reliance on lab-based research) and suggest how to bring more ecological relevance to the field. Taken together, the results of my thesis improve our understanding of how social factors like group-living and cooperation modulate cognitive abilities, and detail the current trajectory of the field of fish cognition.