Understanding the factors that have shaped the evolution of intelligence is a fundamental issue in animal cognition. The social intelligence hypothesis suggests that the physical environment does not present the kind of challenges that lead to the evolution of a flexible, intelligent mind, whereas the social environment does. The hypothesis suggests that social animals will be either generally more intelligent or better at social tasks. Those tasks can encompass many different social questions varying from social learning to the understanding of social relationships.
New research, published in the Psychonomic Society’s journal Learning and Behavior, has started to examine this key question surrounding the relationship between social behavior and intelligence. To do so the researchers compared the abilities of the gregarious chimpanzee and the more solitary black bear to categorize social and non-social stimuli.
Lead researcher Jennifer Vonk from Oakland University explains: “I really wanted to test for evidence of a social concept in a relatively non-social species because I feel like there is a huge paucity of research addressing that question, and we can hardly confirm the Social Intelligence Hypothesis without showing that animals living in social groups actually outperform animals not living in social groups on tests of social cognition.”
It is difficult to test cognition in different species in a truly comparable way. Observed differences could be due to differences in dexterity, testing conditions, general husbandry, and methodology rather than genuine differences in cognitive abilities. Using identical tasks at the same institution with the same researcher allows us to start to explore species differences more accurately.
So, how do we ask these sorts of questions? The touchscreen is a particularly effective tool with which to do this as several species are able to manipulate it in a comparable way. The two species in this study—the chimpanzee and the bear—have color vision and have been shown to behave in a similar way on touchscreen tasks previously. The picture below shows a bear in action in the laboratory.
Animals can be trained to peck or touch a screen in order to receive a food reward. They are then differentially reinforced, receiving food for choosing the “correct” stimulus and a time-out for choosing the “incorrect” one, where the experimenter defines whether or not a stimulus is correct. Thus, the animals are able to learn about the consequences of selecting different stimuli.
The animals in this study were trained on two stimulus sets, one of which required the understanding of a social relationship (in this case it was the mother/offspring relationship). This relationship cannot be acquired through observing similarities in physical characteristics alone, but rather requires an understanding of the relationship between the stimuli. The other stimulus set acted as a control and could be solved based on perceptual cues (simple perceived rules; in this case large and small items of the same type).
Interestingly the bears managed to solve the initial discrimination tasks but were unable to transfer to novel versions of the stimuli, suggesting that they had learned the stimuli by rote and memorized each individual stimulus rather than applying a categorical rule to either stimulus set. There was some evidence of transfer in the chimpanzee.
Vonk summarized “Unfortunately the findings were a bit ambiguous. We had some evidence that the chimp may have eventually acquired the concept of mother/offspring but none did so spontaneously and it didn't seem to be a robust concept for any of the subjects as they did not maintain transfer.”
Though the data are somewhat equivocal, it is possible that the chimpanzee may have learned something about the social concept. If this is found to be the case, then it suggests that more social animals may be better at learning about social stimuli. This study is pioneering in its attempt to pull apart the role that sociality plays in both social and non-social tasks and sets the scene for exciting new experiments investigating key questions in a species appropriate manner. Perhaps one of the greatest challenges in asking cross-species questions is ensuring that these very different animals have an equal chance of solving the task.