Concept learning and memory in California sea lions (Zalophus californianus)

Investigations of animal cognition explore how individuals process and store information about the world. Of special interest is how nonhuman animals solve problems and remember relationships without linguistic codes. While many studies have evaluated the cognitive abilities of animals with respect to specific problems and events, fewer studies have evaluated their concept forming abilities, which involve learning about entire groups of problems rather than the specifics of individual problems. In a series of three papers exploring concept learning in animals, the cognitive performance of California sea lions (Zalophus californianus, Lesson 1828) was investigated under controlled, arbitrary conditions established in the laboratory. These studies, using trained, highly experienced subjects, provide insight into the extents and limits of conceptual behavior in this species.; The first study showed that sea lions are capable of organizing environmental stimuli into useful categories, or equivalence classes. These classes were demonstrated in the contexts of simple and conditional discrimination procedures by the emergence of untrained relations between stimuli sharing common associations with other stimuli or specific types of reinforcers. The results support the notion that some nonhuman animals, like humans, can synthesize previously learned information to solve novel problems. These significant findings were expanded in the second study, which showed that the equivalence classes could also be expanded to include new stimuli through exclusion or "process of elimination" procedures. This study revealed that sea lions can learn new associations in much the same way that children acquire new words during periods of rapid language development. A final study assessed the durability of concepts over long periods of time. The results showed that sea lions are capable of remembering problem solving strategies for at least one and up to ten years.; Collectively, this research shows that sea lions are capable of solving complex problems, developing generalized problem solving strategies, and remembering conceptual information over very long time scales. These cognitive abilities likely facilitate appropriate responding by free-ranging sea lions in a variety of social and ecological settings.