People who have fast eye movements tend to be less patient and are more prone to making quick decisions, according to a recent study.
That’s what researchers from Johns Hopkins University found while studying 23 people and their saccades, or the quick eye movements that occur when we focus on different objects in succession. The researchers used these saccades as a stand-in for body movements.
The study was inspired in part by the team’s curiosity about what makes some people wait in line, while others give up, too impatient to wait their turn. Participants studied a screen in which dots appeared first on one side, and then on the other side, while the researchers recorded the participants’ eye movements using a camera. It turned out there was a lot of variability in the speed of people’s eye movements, although individuals’ own saccades patterns remained pretty consistent.
To determine if the speed of people’s saccades was related to their decision-making and impulsivity, the scientists asked the volunteers to watch the screen again, except this time they were given visual commands to look to the right or to the left. If the command was an X they were supposed to look to the right, and if it was an O they were supposed to look to the left. When they got it right, a buzzer sounded. Then came the waiting challenge. The screen provided commands on where to look, but the volunteers were told that the command would be wrong 25% of the time. A second command, which might be more accurate, followed, but the participants would have to wait some undetermined amount of time for that instruction. By making the most patient individuals wait longer and longer periods of time for the second command, the team figured out the maximum time that participants were willing to wait, and by shortening the time between commands, they also determined the minimum time that the most impatient needed before acting.
“It seems that people who make quick movements, at least eye movements, tend to be less willing to wait,” said Reza Shadmehr, a professor of biomedical engineering and neuroscience at The Johns Hopkins University in a statement. Those with the longest wait times had the slowest eye movements, while those with the shortest wait times had the fastest saccades. That suggests that the way people value time and rewards, and the way they make decisions, may have some physical outlets, such as the speed of eye movements, that can serve as clues as to what’s going on in the brain.
The results may also provide insight into why people with brain injury or mental illnesses such as schizophrenia have problems making decisions; the nervous system evaluates time and reward, and malfunctions in this process may contribute to some of the symptoms of neurological disorders. Quick movements aren’t a harbinger of abnormal mental function, but may be a clue to understanding how and why the brain’s decision-making systems can go awry.