Mechanisms underlying reduction in Stroop interference with practice for young and old adults.

Age-related factors in the reduction of Stroop interference with practice were examined in 3 studies. Young and old adults received extensive practice on a modified version of the Stroop task. Both groups showed reduced interference on the Stroop task with practice. Results suggest that young adults' reduction in Stroop interference was due to general task factors plus the development of a reading suppression response. The old adults' reduction in Stroop interference was attributed primarily to general task factors. Results indicate that old adults have greater difficulty than young adults in developing new automatic processes and modifying existing automatic processes. The implication of these findings for current models of Stroop interference is that, in addition to automatic processing, attentional mechanisms must be incorporated to account for the age-related differences.