Abstract
Attentional orienting is the consequence of a finely tuned interplay between top_down (goal directed) and bottom-up (stimulus-driven) attentional allocation. While the contribution of each type of orienting is well understood in young adults, the degree to which this interplay is affected by aging remains poorly understood. In the present set of three experiments we investigated whether contingent capture, constrained by top-down control, is affected by aging to a lesser extent than the singleton capture (constrained by bottom-up control). Young and older participants viewed a central rapid serial visual presentation (RSVP) stream in which a target letter was either defined by a specific color (e.g., green) or was defined by the virtue of being different from other central letters (e.g., any colored letter embedded among black central letters). On critical trials, an irrelevant colored singleton and three neutral distractors appeared in the periphery. On half of the trials the distractor matched the color of the target while on the other half of the trials the distractor was of a non-matching color. Capture was assessed by measuring the degree of interference in processing the central target letter as a function of whether the distractor matched the target color. We observed that older participants exhibited hypercapture in the contingent capture experiment, such that both the matching colored distractor as well as the non-matching colored distractor interfered with central target processing. This result was different from that observed in young adults who showed capture by a matching colored distractor exclusively. These results suggest that the top-down goals constraining bottom-up attentional orienting in a normal functioning system are compromised with aging, possibly indicating targeted atrophy of the superior parietal lobe with aging.