Like us, jays with higher intelligence have better self-control

A study found that Eurasian jays can pass a marshmallow test, and those with the most self-control also did well on tests of intelligence.

The relationship between self-control and intellect in birds has never been demonstrated before.

Self-control, or the ability to resist temptation in favor of a bigger but later reward, is a key trait that helps people make good decisions and plan for the future.

Jays belong to the corvid family, which is often known as the “feathered apes” because of how cognitively competitive they are with non-human primates. To store food for later, corvids hide it, or “cache” it. In order to prepare for future meals, they must postpone their urge for instant fulfillment. The researchers hypothesize that this may have influenced how self-control evolved in these birds.

According to a prior study by these researchers, self-control has previously been linked to intelligence in chimpanzees, cuttlefish, and humans. The ability to regulate oneself increases with intelligence.

The most recent findings reveal a connection between intelligence and self-control in a variety of distantly related animal groups, indicating that this relationship has independently developed a number of times.

Jays are most susceptible to having their caches stolen by other birds among all the corvids. They can wait for the ideal opportunity to stow their food away without being seen or heard, thanks to their self-control.

The findings were published today in the Royal Society of London’s Philosophical Transactions B journal.

Researchers made an experiment based on the Stanford Marshmallow test from 1972, in which kids could choose one marshmallow right away or two if they waited a certain amount of time. The goal was to see how patient 10 Eurasian jays, Garrulus glandarius, were.

The jays received mealworms, bread, and cheese instead of marshmallows. Mealworms are a popular favorite; bread and cheese are close behind; some people prefer one over the other.

The birds had to pick between mealworms, which they could see but couldn’t reach until a Perspex screen was erected, and either bread or cheese, both of which were immediately available. Could they wait for their favorite cuisine instead of seeking immediate gratification?

The time it took for the bird to get to the mealworm after resisting the urge to eat the bread or cheese was measured. This time ranged from five seconds to five and a half minutes.

All the birds in the experiment were able to wait for the worm, but some birds were able to wait a lot longer than others. At the top of the class was “JayLo,” who turned down a piece of cheese and waited for a mealworm for five and a half minutes. Dolci and Homer, the lowest performers, were only able to wait for a total of 20 seconds.

It’s just incredible how long some jays can wait for their favorite food. I saw JayLo neglect a piece of cheese for more than five minutes during several trials; I was growing impatient, but she was simply waiting for the worm,” said the report’s primary author, Dr. Alex Schnell of the Department of Psychology at the University of Cambridge.

When offered bread or cheese, the jays appeared to be trying to avoid temptation by turning their heads away. Children and chimpanzees both exhibit behaviors that are similar.

Additionally, the researchers gave the jays five cognitive exercises that are frequently used to gauge overall intelligence. The birds who did better on these activities were able to hold off on the mealworm incentive for a little longer. This shows that in jays, self-control and intelligence are related.

Individual birds performed differently; while some performed admirably throughout the board, others performed only mediocrely. “What was most surprising was that if a bird was successful at one of the tasks, it was good at all of them — which shows that a general intelligence element underpins their performance,” said Schnell.

The jays also changed their self-control behavior depending on the situation: in a different trial, when the worm was constantly visible but out of reach, the jays always consumed the bread or cheese that was instantly available. When compared to their third-most-liked food as the immediate reward, the amount of time they were willing to wait for the worm decreased. This adaptability demonstrates that jays only postpone pleasure when it is necessary.

Researchers have discovered that kids who do the Stanford Marshmallow test have a wide range of self-control and that this trait is related to general intelligence. Children who can resist temptation for longer also do better on a wide range of schoolwork.

This study was done in accordance with both the ASAB Guidelines for the Treatment of Animals in Behavioural Research and Teaching and the Home Office Regulations. The University of Cambridge Animal Ethics Review Committee gave permission for this study to be done.