Inside the Fish Brain: Cognition, Learning and Consciousness

Abstract

Detecting and interpreting information about resources and dangers and behaving flexibly and effectively are essential for survival and welfare. Fish, as well as other organisms, access their surroundings through their sensory systems. They must also have a cognitive system capable of integrating and interpreting the sensory input in relation to earlier experiences, and eventually act according to this input. Learning ability and memory enable fish to detect regularities and associations and construct mental images, categories and concepts. In this way, they can adapt their behaviour to the dynamic environment and predict the near future and the consequences of their behaviour. Numerous studies have shown that many fish species have evolved good cognitive abilities, and can construct internal maps, cope with complex social relationships and retain memories for long periods. Some fish can even innovate and use tools. However, the enormous diversity within the piscine world demands that we view learning, cognition and welfare from an ecological perspective. The cognitive capacity of individual species depends on the environmental and social complexity they encounter, and also differs between populations, coping styles and sexes. It is reasonable to believe that fish are conscious and have emotions and feelings, although their subjective experiences must be very different from ours and also vary between species. Their cognitive capacity and the behavioural flexibility that enables them to cope with aquaculture environments and procedures are essential for the welfare of farmed fish.