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Eye movements may predict how people make certain decisions, according to a new study.

Scientists discovered that people who are less patient tend to move their eyes with greater speed.

The latest study examined very simple eye movements, known as saccades, which are movements eyes make as people focus on one thing and then another.  

"They are probably the fastest movements of the body," said Shadmehr. "They occur in just milliseconds."

Previous studies revealed that the speed at which people move could be a reflection of the way the brain calculates the passage of time to reduce the value of a reward. The latest study wanted to see if differences in how subjects moved were a reflection of differences in how they evaluated time and reward.

In the study, participants were asked to look at a screen upon which dots would appear one at a time. Researchers recorded the participants' saccades as they looked from one dot to the other.

While there was a lot of variability n saccade speed among individuals, researchers found very little variation within individuals.

Researchers concluded that saccade speed appears to be an attribute that varies from person to person.

To see if decision-making and impulsivity correlated with saccade speed, participants were asked to look at the screen again. Participants were then given visual commands to look to the right or to the left. If they looked to the wrong direction, a buzzer would be sounded. Participants were told that they would be wrong 25 percent of the time if they followed the command right away.

In some instances the first command would be replaced by a second command to look in the opposite direction. To see how long each volunteer was willing to wait to improve his or her accuracy on that phase of the test, researcher modified the length of time between the two commands based on a volunteer's previous decision.

The findings revealed that the speed of saccades strongly correlated with how long participants were willing to wait.

"It seems that people who make quick movements, at least eye movements, tend to be less willing to wait," said Shadmehr. "Our hypothesis is that there may be a fundamental link between the way the nervous system evaluates time and reward in controlling movements and in making decisions. After all, the decision to move is motivated by a desire to improve one's situation, which is a strong motivating factor in more complex decision-making, too."

The findings are published in The Journal of Neuroscience.