Stimulus onsets and distraction in younger and older adults

Changes in task performance that accompany healthy aging are often attributed to age-impaired inhibitory control. For example, Maylor and Lavie (1998) demonstrated greater interference in older than younger people for response-incompatible visual distractors presented peripherally to a central low-load task. Here we explore the possible contribution of age-related changes in bottom-up visual processing in this task, and specifically the effect of the abrupt visual onsets associated with the distractors. In Experiment 1, with distractors presented as abrupt onsets, we replicated Maylor and Lavie's (1998) effect. In Experiment 2, when placeholders preceded the stimuli to eliminate the abrupt onsets, response-incompatible distractors had a markedly reduced effect relative to neutral distractors, for older participants in particular. Stimuli presented as abrupt visual onsets, therefore, capture attention differentially depending upon the stimulus identity in combination with the age of the individual, with the greatest effects here for response-incompatible distractors in older people. We conclude that age-related differences in basic bottom-up processes may contribute to many purported declines in higher-level functioning in older people. More generally, this study provides further evidence for the interaction, and nonadditivity, of stimulus-driven and goal-driven influences in determining processing priorities across the age span.