Age, color processing and meaningfulness: an event-related potential study.

The effects of aging on event-related potentials (ERPs) and reaction time (RT) performance were investigated in a task that combined color discrimination and lexical decision. The stimuli were either words or non-words, presented either in the relevant or in the irrelevant color. RT responses were required to words in the relevant color. Stimuli appeared in the relevant color elicited attention-related ERP components (anterior positivity, selection negativity and N2b). The latency values of the attention-related ERP components and the RT were longer in the older group, indicating the slowing down of attentional processes in the elderly. In the older group the late positivity to stimuli in the relevant color was absent over the posterior locations. Unlike in the older group, in the younger subjects the words appeared in the irrelevant color elicited a central negative wave in the 400 ms range. These results are considered as a capacity limitation in the elderly in processing of the stimulus characteristics beyond to the actual stimulus-response contingencies.