Contact:
Jeremy Craig, 404-413-1357
Georgia State University
Mary Platt, 714-628-7271
Chapman University
ATLANTA — Researchers at Georgia State University and Chapman University have found that other primates besides humans perform just as well when coordinating to make decisions.
Sarah Brosnan, assistant professor in GSU’s Department of Psychology and Neuroscience Institute, and Michael Beran, senior research scientist at GSU’s Language Research Center; and Bart Wilson, the Donald P. Kennedy Endowed Chair of Economics and Law at Chapman University tested humans, rhesus monkeys and capuchin monkeys using a computerized game.
The “Assurance game” used in the experiment has each player selecting either “stag” or “hare,” and different levels of rewards were given for the partners’ responses. Mutual “stag” plays received the most payoff (food in the monkeys’ case and money in the humans’), followed by mutual “hare.”
When there was an uncoordinated play, the partner who played “stag” received nothing while the individual who played “hare” received a small payoff. All performed well in the game when they had clues to their partners’ choices, but rhesus monkeys did just as well as humans when there were no cues at all. The research is published in the Proceedings of the Royal Society, Series B.
“It was remarkable how well the rhesus monkeys did at this task,” Brosnan said. “We did not anticipate them finding the coordinated outcome as easily as did the humans, so one of the questions we are currently most interested in is whether they are using the same mechanisms as the humans as well.”
While humans had the advantage of language, they could also solve the problem without it, as the rhesus monkeys did.
“Moreover, we now know that humans, at least, can solve coordination problems in multiple ways,” she added. “Some of these, such as language, are unique to humans but some may be shared with other species.”
While outcomes might be the same between species, it doesn’t always necessarily mean that there are similar behavioral mechanisms involved, Brosnan explained.
“Natural selection works with whatever is already present in the species, so an outcome that is beneficial might be reached using different mechanisms,” she said. “One of our ongoing projects is investigating whether or not humans and rhesus monkeys are using the same mechanisms to reach this coordinated outcome.”
The nonhuman primate research was performed at Georgia State’s Language Research Center, and was supported by grants from the National Science Foundation and the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) of the National Institutes of Health. The human subjects research was performed at Chapman University’s Economic Science Institute, and was supported by the National Science Foundation.
To access the study in the Proceedings of the Royal Society B, visit http://rspb.royalsocietypublishing.org/lookup/doi/10.1098/rspb.2011.1781.
Nov. 9, 2001