Cognitive mediation of adult age differences in language performance.

Young (M = 20 years) and old (M = 68 years) adults completed language processing tasks, measures of working memory capacity (backward span and the n-back lag task), inhibitory efficiency (Stroop interference), and processing speed (color naming). regression analyses revealed that each of the resource measures significantly predicted language performance and attenuated variance in language performance that would otherwise be attributed to age. When speed variance was entered into the equation first, the mediating influence of the inhibition and working memory measures remained significant. When speed and inhibition differences were controlled, the working memory measures could not reliably predict language performance. These results suggest that language performance differences may be fundamentally mediated by age differences in processing speed and inhibitory efficiency.