Inattentional blindness in older adults: Effects of attentional set and to-be-ignored distractors.

Inattentional blindness (IB) involves failing to detect an unexpected visual stimulus while undertaking another task. Previous research has predominantly investigated IB using young adult samples, with few studies exploring whether or how an observer's age affects their detection of unexpected events. To help address this gap, we compared younger adults (18-25 years of age) and older adults (60-80 years of age) on two IB tasks: one dynamic, one static. In the static task, older age was associated with substantially increased IB rates: 89 % for older adults versus 5 % for younger adults. In the dynamic task, we systematically manipulated the presence of to-be-ignored distractors and whether the unexpected stimulus color matched the observers' attentional set. We found a main effect of age on IB: As in the static task, older age was associated with increased IB rates (38 % for older adults vs. 8 % for younger adults). The presence of to-be-ignored distractors and attentional set mismatch interacted to substantially increase IB rates, but age did not interact with either factor. Overall, the results indicate that older age is associated with large increases in IB rates across a range of tasks. The pattern of results is consistent with attentional capacity models of cognitive aging, suggesting that older adults' reduced cognitive resources result in failure to consciously process stimuli that are inconsistent with their attentional set.