Eye movements as a predictor of behavior
In a research paper Johns Hopkins Biomedical Engineering professor Reza Shadmehr and his team shared their findings on the relationship between rapid eye movement and decision making. The decision making targeted in this research was related to human behavior: impulsiveness vs patience — specifically how the brain perceived the value of reward set against time investment. In addition, the study sought to test the idea that there was a correlation between vigor of movements and the tendency for impulsivity.
Dr. Shadmehr worked with collaborators, Jennie Choi and Pavan Vaswani — both from the Johns Hopkins University School of Medicine. They were able to measure very simple eye movements, called saccades (the fastest movement of the body) while testing response to controlled tests. In the controlled tests, study participants were exposed to a series of increasingly patience-challenging experiments. The group’s responses at various testing levels could then be compared. By combining eye movement data with the individual’s choices the team was able to make conclusions. The tests determined how long each subject was willing to wait to acquire better odds of success.
When the speed of the volunteers’ saccades was compared to their impulsivity during the patience test, there was a strong correlation. “It seems that people who make quick movements, at least eye movements, tend to be less willing to wait,” says 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 research paper entitled Vigor of Movements and the Cost of Time in Decision Making was published in Jan. 2014 in the Journal of Neuroscience. The research found that the weight people give to the passage of time may be a trait consistently used throughout their brains, affecting the speed with which they make movements, as well as the way they make certain decisions.