AGING AND COGNITIVE VIGILANCE - EFFECTS OF SPATIAL UNCERTAINTY AND EVENT RATE

Age-related differences in cognitive vigilance were examined in a task requiring identification of a target (a lowercase letter) presented a t three levels of spatial uncertainty (low, moderate, and high) and in the context of a low or high event rate. Thirty-six young (18-24 year s) and 36 older (60-74 years) adults participated in 30-min vigilance sessions. Increased spatial uncertainty decreased target detection rat e and d' to a greater extent in older adults than in young adults. No age differences were obtained for the law-spatial-uncertainty conditio n. The vigilance decrement-the decline in detection rate over time-was magnified when event rate was high and when spatial uncertainty was h igh. The results suggest that cognitive vigilance is age sensitive whe n demands on visual attention capacity are increased by high event rat e or spatial uncertainty.