Cognitive mediators of age-related differences in language comprehension and verbal memory performance

The present study tried to specify how much processing speed, working memor y capacity, and inhibition capability contribute to the effects of aging on language performance. An individual-differences approach was used to exami ne the component processes that predict performance in language comprehensi on and verbal long-term memory tasks. A total of 151 participants aged 31-8 0 completed language processing tasks and a battery of tasks designed to as sess processing speed, working memory, and resistance to interference. Late nt-construct structural equation modeling was used to examine the relations hips of these factors and age to different types of language tasks. The bes t fit model showed first that all the significant relationships between age and language performance are mediated through reductions in speed, resista nce to interference, and working memory; this confirms the validity of the general factor approach of agerelated differences in cognitive performance. The best fit model, however, also showed that the contribution of speed an d resistance to interference is indirect and mediated by working memory, wh ich appears to play a crucial role in explaining age-related differences in language performance.