The six chimpanzees participating in the game consisted of three pairs of mothers and their offspring. The sixteen human participants were all Japanese university students. Humans and chimps did not directly compete. Humans played with humans, and chimps with chimps.
In the game, two players sit back-to-back to each other facing a computer screen. They choose either a box on the left or a box on the right on the touch screen. One player's goal is to choose the same box as the other player, and the other player's goal is to choose a different box from the opponent's. The game was repeated 200 times. Winning chimps received apple chunks and humans won 1 Yen. Prizes were distributed immediately after each round.
Researchers found that the chimps were much better than humans in recognizing patterns to predict their opponent's selections. "Chimps are really good at adjusting and gaining a competitive edge if there is a little bit of a slip by their opponent, until generally they are both balanced," said Colin Camerer, a professor of behavioral economics at the California Institute of Technology and the study's lead researcher in an interview with USA Today network.
The experiment was also conducted with 12 adult men in Bossou, Guinea. Instead of computer images, bottle caps were used. The participants faced each other and placed the caps either right side up or upside down. The same matching or mismatching goals were used, but the reward for the winners was very high - a full day's earnings. The men did not outperform the chimps either, rather they performed about as well as the Japanese students.
In game theory, there is a concept called the Nash equilibrium which states that there is a limit to how many times a strategic game can be won based on how well a player can predict his opponent's move. The chimps were so good at the game that they came very close to hitting the theoretical limit for how many times the game can be won. The humans did not even come close.
It trying to explain the differences between the performance of the chimps and the humans, the researchers discussed several factors. One thought was that the chimps were related to one another and therefore may have insight into how their opponents would perform, but this does not appear to be a valid explanation. For one thing, the kinship could make the chimps less competitive with one another. Also, although the students were strangers, the men in Guinea knew each other.
Another possible issue was the effect of the awards. The chimps were highly motivated by the food reward, which could improve their performance. However, this seems not to be the case either, as the students were relatively unmotivated by their low payout (the equivalent of about $.0098), while the men in Guinea were highly motivated by a very large financial reward, but the two human groups performed about the same.
The researchers believe that the chimps performed so well because they have extremely good short-term memory which allowed them to memorize their opponents' strategies. It is also thought the chimps prevailed because they live in a much more competitive environment than humans where more nonverbal communication is used.
Rahul Bhui, a California Institute of Technology graduate student and study co-author says, "Fights with other chimps and dominance hierarchies are central to their lives. We have language and widespread cooperation which (chimps) don't need to worry about, and maybe that impairs our performance in these simple competitions. Maybe these were costs we paid for other abilities."