With extensive systems of governance and global cooperative networks in place, we probably think we are expert co-operators when compared with other animals or even relative primates, such as chimpanzees and capuchin monkeys.
But how much of this cooperation depends on our ability to speak? Apparently more than we would believe, reports ABC News. Psychologists at the Language Research Centre at Georgia State University conducted a cooperative-rewards game in which participants - be they man, monkey or chimp - had to work in pairs. The game required participants to cooperate to get the biggest payout - quarters and dollars for the humans, and tasty fruits for the primates. When humans were not told the rules of the game and had to figure things out non-verbally, the way their chimp and capuchin monkey primate counterparts had to, human cooperation did not far outperform that of the other primates.
"Normally, we expect to see 100 per cent cooperation with humans when they know the rules of the game. When we had them go in blind, only five pairs out of 26 developed the best scenarios of cooperation. That’s only 20 per cent,” said lead author Sarah Brosnan.
Humans still outperformed the other primates, who were chosen because they were notoriously cooperative species, but the extent to which the lack of language handicapped the human pairs was surprising, she said.
"We can explain that because it means that humans are very reliant on language,” she added.
The study also found that a third of the human pairs happened upon the low reward scenario, just a quarter per round, and then stuck with it throughout the rest of the game. This means that the humans were risk-resistant, or they assumed they had ‘beat’ the game already.
Often in studies that compare human and primate behaviours, humans are given an inherent advantage because they get to know the rules of the game or task while the primates have to just ‘figure it out’.
"In normal experimental economic games, people are brought into the lab and given a full explanation of what the payoffs are ahead of time. In more complicated games, they even do a pre-test to be sure that everyone understands the task at hand. But you can’t do that with primates. So in this case, we wanted to see what would happen if we did everything the same,” said Brosnan.
So the humans were told they were part of an experiment involving decision making using red and blue chips, but they were not told anything else. Surprisingly, despite the simplicity of the game, several of the pairs never quite figured it out, and only 58 per cent developed a specific game strategy. When all was said and done, 31 per cent of human pairs failed to perform better than chance.
"This tells us that when doing human-primate comparisons, it’s essential to make the situation as comparable as possible,” said Brosnan.
But this experiment tells us more than that, said Daniel Houser, a professor of economics at George Mason University.
"This study speaks to the way human society looks in the absence of an understanding of the rules,” he said.
When the rules of a simple economic cooperation game are communicated, humans cooperate almost 100 per cent of the time. "But when the rules are not clear and there’s no verbal communication, it becomes very difficult to choose outcomes that are mutually beneficial,” Houser pointed out.
The study is published in the Proceedings of the National Academy of Sciences.