Chimpanzee taking a number test on a touch screen
Akiho Muramatsu
Audience pressure can affect human performance both positively and negatively, and it turns out the same is true for our closest relatives.
Kristen Lin He and his colleagues at Kyoto University in Japan tested groups of six chimpanzees kept at the university’s Primate Research Institute on three numerical tasks of varying difficulty.
In the first task, numbers from 1 to 5 appeared in random positions on the screen, and the chimpanzees simply had to touch the numbers in the correct order to receive a reward.
In the second task, the numbers were not adjacent. For example, 1, 3, 5, 7, 11, 15 might appear on the screen. Again, the chimpanzees had to press a number from the minimum value to the maximum value to receive a reward.
Finally, in the most difficult test, when the first digit in the sequence was pressed, the remaining digits were hidden behind a checkered square on the screen. This meant that the chimps had to memorize the positions of the numbers in order to press them in the correct order.
The chimpanzees were tested on this task thousands of times over six years with a variety of audiences, including one to eight human observers, people familiar with chimpanzees, and people new to chimpanzees.
When the task was easy, the chimpanzees performed worse as more people watched. However, on the most difficult task, all six chimpanzees performed better as the audience size increased.
“It was very surprising that performance improved so much as the number of human experimenters increased, because having more humans present can be distracting,” Lin says. “However, the results suggest that this may actually motivate them to perform even better.
“For the easiest tasks, humans may distract them, but for the most difficult tasks, humans can become a stressor and actually motivate them to perform better.”
team members Shinya YamamotoResearchers from Kyoto University also said they were surprised to find this effect in chimpanzees.
“Such audience effects are thought to be unique to humans who live in reputation-based and normative societies, where it is possible to perform well in front of an audience, and others to perform well in front of an audience. Sometimes they perform worse than they do,” he says. “However, our study shows that this audience effect may have evolved in the ape lineage before this type of normative society developed.”
Yamamoto says it’s difficult and sometimes dangerous to derive direct human implications from non-human research. “But chimpanzees are the same way!” If you casually say, “Chimpanzees are the same way!”, you might be able to calm down someone who is extremely nervous in front of others.”
Miguel Llorente Researchers from the University of Girona in Spain suggest that further research could be done into how audience effects relate to individual chimpanzee personalities.
“To generalize these results to natural behavior in chimpanzees, we will investigate these effects with chimpanzee audiences to more fully understand how these dynamics play out in natural social contexts.” “It would also be interesting to understand that,” he says.
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