Chimpanzees perform better on difficult tasks when there is an audience

Pressure from a viewing audience can have positive or negative effects on human performance, and this has been shown to be the case even for our closest relatives.

Christine Lin Researchers at Kyoto University in Japan tested three numerical tasks of varying difficulty in a group of six chimpanzees housed in the university’s primate research center.

In the first task, numbers 1 to 5 were displayed at random locations on the screen, and chimpanzees simply had to touch the numbers in the correct order to receive a food reward.

In the second task, the numbers were not adjacent. For example, 1, 3, 5, 7, 11, and 15 might appear on the screen. Again, the chimpanzee had to press numbers from the smallest to the largest to receive the reward.

Finally, in the most difficult test, when the first number in a sequence was pressed, the remaining numbers were hidden behind checkered squares on the screen. This means that chimpanzees have to remember where the numbers are in order to press them in the correct order.

The chimpanzees tested the task thousands of times over six years with a variety of audiences, including one to eight human observers, some familiar with chimpanzees and others new to them.

When the task was easy, the more people there were watching, the worse the chimpanzees performed. However, on the most difficult task, all six chimpanzees performed better as the audience size increased.

“It is quite surprising that performance improves significantly as the number of human experimenters increases, since one would expect that the presence of more humans would lead to greater distraction,” says Lin. “But the results suggest that this may actually motivate people to perform better.

“For the easiest tasks, humans may be distracted, but for the most difficult tasks, it is likely that it is the stressors that actually motivate humans to perform better.”

team member Shinya YamamotoResearchers, also at Kyoto University, said they were surprised to discover this effect in chimpanzees.

“This audience effect is often thought to be unique to humans living in reputation-based norm societies. Sometimes we do better in front of an audience, and sometimes we do worse than expected,” he says. “But our research suggests that this audience effect may have evolved in the great ape lineage before this kind of normative society developed.”

Yamamoto says directly influencing humans from non-human research is difficult and sometimes dangerous. “But you can probably ease the nerves of people who are extremely nervous in public by casually telling them that chimpanzees are the same!”

Miguel Llorente Researchers from the University of Girona in Spain have proposed further research that could explore how audience effects relate to individual personalities in chimpanzees.

“In order to generalize these results to the natural behavior of chimpanzees, it would also be interesting to explore these effects with an audience of chimpanzees to more fully understand how these dynamics operate in natural social contexts,” he says.