Time Stress Interacts with Coding, Density, and Search Type in Visual Display Search

Twelve subjects participated in a study of time stress in visual display search and the relationship between stress and other variables known to affect visual search, such as symbol density, color coding, and search type. Response time (RT) differed significantly for each of these variables and for their two-way interactions. Generally, time stress suppressed the affects of the other variables. Accuracy varied significantly only for the main effects of coding, search type, and density. In addition to RT and accuracy, several ocular measures were collected. Results for the number of eye fixations paralleled the RT results except for the stress and practice (day) variables. Fixations per second approached significance for day and search type effects. Differential patterns of significant effects were observed for eye blink and pupil diameter changes that reflected stress, cognitive load, and search difficulty.