Working memory, language comprehension, and aging: four experiments to understand the deficit.

Four experiments were carried out to investigate working-memory capacity and functioning in young and older subjects, and its relation with reading comprehension. Experiment 1 showed that older subjects had to trade off processing and storage functions, due to an assumed reduced pool of resources relative to young subjects. Working-memory measures were weakly correlated with reading comprehension in each age group. Experiment 2 revealed a specific processing impairment in older subjects, and showed that older subjects tended to sacrifice the maintenance of the concurrent mnemonic load to devote more resources to ongoing processing. In Experiment 3, the age-related differences in the processing/storage trade-off were again observed. Furthermore, differences in the speed/accuracy trade-off were revealed. Experiment 4 showed that whatever the instructions regarding the speed/accuracy trade-off, the older subjects remained slower and slightly more accurate than the young subjects. In conclusion, it appears that the age-related differences in working memory are both structural and functional. Different strategies may be implemented in each age group to deal with reading comprehension.