How lemurs and monkeys exploit the social wisdom of crowds
If you want to keep up with the humans, it’s better if you’re a social animal: That’s the lesson learned from two studies focusing on the group dynamics and problem-solving skills of lemurs and squirrel monkeys.
In one study, six different species of lemurs were tested to see how savvy they were about stealing food when their human monitors weren’t watching. In the other study, researchers studied two groups of squirrel monkeys to measure how quickly they learned how to open a puzzle box and get at the food inside.
"Both papers highlight the cognitive benefits of being in a social environment," said Duke University’s Evan MacLean, the lead researcher for the lemur study appearing in the journal PLOS ONE.
In the species-to-species comparison, the lemurs who lived in bigger groups were more likely to try stealing a piece of food if the human wasn’t watching them. The finding suggests that living in larger groups carries over to solving problems that call for figuring out what others might do. That may have given early humans an advantage hundreds of thousands of years ago.
Read more at [nbcnews.com]
Group Size Predicts Social But Not Nonsocial Cognition in Lemurs [PLoSONE]
Abstract: The social intelligence hypothesis suggests that living in large social networks was the primary selective pressure for the evolution of complex cognition in primates. This hypothesis is supported by comparative studies demonstrating a positive relationship between social group size and relative brain size across primates. However, the relationship between brain size and cognition remains equivocal. Moreover, there have been no experimental studies directly testing the association between group size and cognition across primates. We tested the social intelligence hypothesis by comparing 6 primate species (total N = 96) characterized by different group sizes on two cognitive tasks. Here, we show that a species’ typical social group size predicts performance on cognitive measures of social cognition, but not a nonsocial measure of inhibitory control. We also show that a species’ mean brain size (in absolute or relative terms) does not predict performance on either task in these species. These data provide evidence for a relationship between group size and social cognition in primates, and reveal the potential for cognitive evolution without concomitant changes in brain size. Furthermore our results underscore the need for more empirical studies of animal cognition, which have the power to reveal species differences in cognition not detectable by proxy variables, such as brain size.
Diffusion Dynamics of Socially Learned Foraging Techniques in Squirrel Monkeys [CurrentBiology]
Abstract: Social network analyses and experimental studies of social learning have each become important domains of animal behavior research in recent years yet have remained largely separate. Here we bring them together, providing the first demonstration of how social networks may shape the diffusion of socially learned foraging techniques. One technique for opening an artificial fruit was seeded in the dominant male of a group of squirrel monkeys and an alternative technique in the dominant male of a second group. We show that the two techniques spread preferentially in the groups in which they were initially seeded and that this process was influenced by monkeys’ association patterns. Eigenvector centrality predicted both the speed with which an individual would first succeed in opening the artificial fruit and the probability that they would acquire the cultural variant seeded in their group. These findings demonstrate a positive role of social networks in determining how a new foraging technique diffuses through a population.