Age-related differences in visual search task performance: relative stability of parallel but not serial search.

The hypothesis that visual search tasks requiring effortful, serial processing are more sensitive to aging than those requiring relatively automatic, parallel processing was tested in 96 healthy adults who performed parallel and serial visual search tasks with fixed presentation times. Reaction times and error rates increased with age in both tasks, but there was no difference between young and old in the effect of increasing numbers of distractors on reaction times. However, the older subjects made significantly more errors with increasing numbers of distractors in the serial search task. Older subjects have disproportionately more difficulty performing serial compared to parallel visual search tasks than do younger subjects. Additionally, this difference is not caused solely by cautious response strategies in the elders.