Aging involves selective changes in attentional control. However, its precise effect on visual attention is difficult to discern from behavioural studies alone. In this paper, we employ a recently developed phase-locking measure of synchrony as an indicator of top-down/bottom-up control of attention to assess attentional control in the elderly. Fourteen participants (63-74 years) searched for a target item (coloured, oriented rectangular bar) among a display set of distractors. For the feature search condition, where none of the distractors shared a feature with the target, search time did not increase with display set size (two, or four items). For the conjunctive search condition, where each distractor shared either a colour or orientation feature with the target, search time increased with display size. Phase-locking analysis revealed a significant increase in high gamma-band (36-56 Hz) synchrony indicating greater bottom-up control for feature than conjunctive search. In view of our earlier study on younger (21-32 years) adults (Phillips and Takeda, 2009), these results suggest that older participants are more likely to use bottom-up control of attention, possibly triggered by their greater susceptibility to attentional capture, than younger participants.
Copyright (c) 2009 Elsevier B.V. All rights reserved.