Research has demonstrated the difficulties experienced by older adults when they are engaged in visual search. This article reports on a study in which the effects of divided attention were examined in younger adults (M = 23 years) and older adults (M = 64 years) who searched for traffic signs in digitized images of traffic scenes. The model required sign searching under single-task and dual-task conditions, in scenes containing either small or large amounts of visual clutter. The results showed that for both age groups, clutter and the secondary task had additive effects on search accuracy, speed, and oculomotor involvement. In the dual-task condition, participants were less accurate at identifying the signs, took longer to do so with searches that involved more eye movements, and exhibited prolonged fixations indicative of more effortful processing. And, compared with the younger adults, older adults were less accurate, especially with high-clutter scenes, were slower to decide that a target sign was not present, and exhibited a marginally greater divided-attention effect on reaction times. The older adults exhibited longer fixations in the divided-attention condition, in which they also showed a disproportionate reduction in recognition memory for the content of the secondary task.
Abstract