Brainy Monkeys Outsmart Humans In Cognitive Flexibility Experiment


Rachel Baxter

Copy Editor & Staff Writer


You're a fool, human. Or maybe we just got a better reward. Yoyochow23/Shutterstock 

We humans like to think of ourselves as superior to all other beings on Earth, but every now and then we get outsmarted. The latest example comes from two wily species of monkey, the tufted capuchin and the rhesus macaque. It turns out, when it comes to problem-solving, these primates are quick to switch to a novel yet more efficient solution, while humans stick with what they know.

A new study, published in Scientific Reports, pitted monkeys and humans against each other using a simple computer game. The participants had to follow a specific pattern, touching a striped square on the screen followed by a dotted square and then, once it appeared in front of them, a triangle. They learned the sequence via trial and error, receiving a reward when they got the sequence right. Human volunteers heard an encouraging “whoop” when they succeeded, while the monkeys got a tasty banana-flavored food pellet. If they failed, they experienced a quick timeout and got no reward, with the humans hearing a disheartening buzz.


Next, to test how easily the two groups would switch to a more efficient method of getting the reward, they were given the option of pressing a triangle straightaway. Not easily fooled, the monkeys quickly realized that touching the triangle immediately got them a treat. A total of 70 percent of them used the shortcut the first time it was presented to them, while a pathetic 1.7 percent of the humans (one out of 56) did the same. The study involved 29 monkeys, seven rhesus macaques and 22 capuchins.

All of the monkeys had used the shortcut by their eighth go, whereas the humans, if they switched strategy at all, had done so by attempt 43 on average. Over time, the humans did increasingly use the shortcut, but the monkeys were certainly much quicker off the mark when it came to adapting their behavior to access the reward.

The options presented to the participants. Arrows indicate the correct shape to be selected, with the direct strategy being the ideal shortcut, and the switch strategy being a slightly less effective shortcut. Watzek et al./Scientific Reports 2019; CC BY 4.0

"We are a unique species and have various ways in which we are exceptionally different from every other creature on the planet," said Julia Watzek, a graduate student in psychology at Georgia State University, in a statement. "But we're also sometimes really dumb."

It seems when it comes to cognitive flexibility – the ability to adapt one’s behavior based on new information from the environment – monkeys rise above us. Meanwhile, humans exhibit cognitive set bias, which means they prefer to use a method that they know works and are accustomed to, rather than branching out and using a new technique, even if that new technique is more effective.


“We found that capuchin and rhesus monkeys successfully used the shortcut at high rates, soon after it first became available,” the researchers wrote. “In doing so, they join the ranks of baboons and chimpanzees in outperforming humans, who tend to stick with the less efficient but familiar learned strategy.”

If you’re disheartened to learn that your species has been outwitted by a team of monkeys, the researchers note that the humans were quicker to learn the sequence of shapes in the first place. This might have contributed to their greater cognitive set bias, as the pattern might have been more strongly ingrained in their brains, but more research is needed to find out.

A similar study that compared cognitive flexibility in humans and baboons by looking at adults and children visiting Atlanta Zoo found that children between the ages of 7 and 10 were four times more likely to use the shortcut than adults, although half still stuck with the method they knew.

Perhaps us grown-ups aren’t quite as wise as we like to think.