There is some evidence to suggest that certain species of birds, including jays, may exhibit variations in self-control abilities that are related to their cognitive abilities. For example, a study published in the journal Science in 2014 found that Eurasian jays with higher cognitive abilities were better at exercising self-control than those with lower cognitive abilities.
According to one study, Eurasian jays can pass a version of the “marshmallow test,” and those with the most self-control also perform well on intelligence tests. This is the first proof of an association between self-control and intelligence in birds.
Self-control is a crucial skill that underpins effective decision-making and future planning. It is the ability to resist temptation in favor of a better but delayed reward. Jays are corvids, also known as “feathered apes” because their cognitive abilities rival those of non-human primates. Corvids hide their food, or ‘cache’ it, to save it for later. In other words, they must postpone immediate gratification in order to plan for future meals. The researchers think this may have driven the evolution of self-control in these birds.
Self-control has been previously shown to be linked to intelligence in humans, chimpanzees and – in an earlier study by these researchers – in cuttlefish. The greater the intelligence, the greater the self-control.
The birds’ performance varied across individuals – some did really well in all the tasks and others were mediocre. What was most interesting was that if a bird was good at one of the tasks, it was good at all of them – which suggests that a general intelligence factor underlies their performance.
Dr Alex Schnell
The new findings show that the relationship between intelligence and self-control exists in distantly related animal groups, implying that it has evolved independently several times. Jays, more than any other corvid, are vulnerable to having their caches stolen by other birds. They can also hide their food without being seen or heard because they have self-control.
The findings were published in the journal Philosophical Transactions of the Royal Society B.
To assess the self-control of ten Eurasian jays, Garrulus glandarius, researchers devised an experiment based on the 1972 Stanford Marshmallow test, in which children were given the option of one marshmallow right away or two if they waited a certain amount of time.
Instead of marshmallows, the jays were presented with mealworms, bread and cheese. Mealworms are a common favourite; bread and cheese come second but individuals vary in their preference for one over the other.
The birds had to choose between bread or cheese, which were immediately available, and mealworm, which they could see but couldn’t get to until a Perspex screen was raised. Could they put off immediate gratification in order to eat their favorite food?
There was a five-second to five-and-a-half-minute delay before the mealworm was made available if the bird had resisted the temptation to eat the bread or cheese. All of the birds in the experiment were able to wait for the worm, but some were able to do so for much longer than others. ‘JayLo,’ who ignored a piece of cheese and waited five and a half minutes for a mealworm, was the class winner. The worst performers, ‘Dolci’ and ‘Homer’, could only wait a maximum of 20 seconds.
“It’s just mind-boggling that some jays can wait so long for their favorite food. In multiple trials, I sat there watching JayLo ignore a piece of cheese for over five minutes – I was getting bored, but she was just patiently waiting for the worm,” said Dr. Alex Schnell at the University of Cambridge’s Department of Psychology, first author of the report.
When presented with bread or cheese, the jays looked away, as if to distract themselves from temptation. Chimpanzees and children have shown similar behavior. In addition, the researchers gave the jays five cognitive tasks that are commonly used to assess general intelligence. The birds who performed better in these tasks were also able to wait for the mealworm reward for a longer period of time. This suggests that in jays, self-control is linked to intelligence.
“The birds’ performance varied across individuals – some did really well in all the tasks and others were mediocre. What was most interesting was that if a bird was good at one of the tasks, it was good at all of them – which suggests that a general intelligence factor underlies their performance,” said Schnell.
The jays also adapted their self-control behavior to the circumstances: in another experiment, where the worm was visible but always out of reach, the jays always ate the closest bread or cheese. And the length of time they were willing to wait for the worm decreased when it was compared to their second most preferred food as an immediate treat, rather than their third. This adaptability demonstrates that jays only postpone gratification when necessary.
Other researchers have discovered that children taking the Stanford marshmallow test vary greatly in their self-control, and that this ability is related to their general intelligence. Children who can resist the temptation for a longer period of time perform better in a variety of academic tasks.
