PUB - Publikationen an der Universität Bielefeld

Examining the eye movements of a person during their performance of a task offers a way to gain deeper insights into ongoing cognitive processes of that person. A body of work suggests that the peak velocity of a saccade is related to the cognitive demands of a task. Recently, we recorded eye movements of participants while they performed a version of a computerized Trail-Making-Test (TMT), a popular test of executive functions applied in neuropsychological contexts. During the test participants clicked through a sequence of numbers (TMT-A) or alternated between a sequence of numbers and letters (TMT-B) emphasizing either the speed or the accuracy of their responses. Since part A and part B generally differ in their task difficulty, we examined if the saccadic peak velocities were reflective of that difference. Our analyses revealed peak velocities were greater during performance of TMT-B but only when participants were emphasizing the speed of their responses. TMT-A performance yielded no such differences. We suggest that this is due to the combination of test part B with the speed task-set. The speed task-set might amplify the effect of task difficulty on the level of arousal which becomes visible in higher saccade peak velocities. In contrast, the accuracy task set might limit the effect of task-difficulty on arousal, to ensure an appropriate level of carefulness in task performance. Taken together, these findings highlight saccade velocities as a tool to uncover cognitive and physiological states in sensorimotor tasks.