Measuring Sustained Attention and Perceived Workload

We examined the effects of spatial uncertainty, field dependence/independence (FD/I), and sex on vigilance performance and perceived workload in elementary school children.

Building on previous work in which children demonstrated their ability to evaluate workload, we tested whether spatial-uncertainty manipulations in a vigilance task would elicit in children the same deleterious effects on performance and workload as it does with adults. We also examined individual difference effects associated with FD/I and sex to determine their influence on both performance and workload.

In the low-uncertainty task, stimuli appeared in the center of the computer screen; in the high-uncertainty task, they appeared in one of the four quadrants of the screen. Neutral events consisted of uppercase letter strings. Critical signals consisted of a single lowercase letter among uppercase letters. Following each vigil, children completed a workload assessment via a modified version of the NASA Task Load Index.

Children showed lower perceptual sensitivity, greater response latency variability (RT^SD), and a higher response criterion in the uncertain display condition. Workload scores reflected these performance differences. Field-dependent children showed lower perceptual sensitivity and greater RT^SD than did field-independent children. The two groups exhibited differing workload profiles. Despite no objective performance differences, boys reported greater workload than girls.

The scale demonstrated sensitivity and diagnosticity with regard to both the task variable and individual differences.

These findings contribute to the emerging field of "educational ergonomics" and indicate that appropriate assessment tools might identify children who are experiencing increased workload.