Aging and temporal patterns of inhibition of return

Inhibition of return (IOR), an inhibitory component of spatial attention that is thought to bias visual search toward novel locations, is considered relatively well preserved with normal aging. We conducted two experiments to assess age-related changes in the temporal pattern of IOR. Inhibitory effects, which were strongly reflected in the performance of both younger adults (ages 18-34 years) and older adults (ages 60-79 years), diminished over a period of 5 s. The time point at which IOR began to diminish was delayed by approximately 1 s for older adults compared with younger adults; this pattern was observed on both a target detection task (Experiment 1) and a color discrimination task (Experiment 2). The finding that timing characteristics of IOR are altered by normal aging has potential implications for the manner in which inhibition aids search performance.