ADULT AGE-DIFFERENCES IN THE TIME COURSE OF VISUAL-ATTENTION

On each trial in this experiment, subjects made a choice response regarding which of two target letters was present in a visual display. A cue, occurring between 50 and 183 ms prior to display onset, indicated the location of the target. The results indicated that reaction time (RT) increased as a function of both the distance of the target from fixation and the presence of nontarget letters in the display. These RT effects were more pronounced for older adults than for young adults, in a manner consistent with a generalized age-related slowing of visual processing. The changes in RT associated with the cue indicated that, when nontarget letters were present in the display, the buildup of attention over the cue-target interval was slower for older adults than for young adults. This age difference in the time course of attention was independent of the generalized age-related slowing.