Semantic memory and reading comprehension: the relationship through adulthood and aging.

Literature shows a relationship between working memory and reading comprehension during lifespan and aging. In addition, a difference between genres of text was shown: the expository text affects the already limited cognitive resources of the older adults, whereas narrative text comprehension seems to be preserved. Undoubtedly, also semantic knowledge plays a key role in reading comprehension; though, and to our knowledge, there are no studies clearly showing the relation between semantic knowledge and reading comprehension in aging. In the current study, we administered to younger adults and older adults a semantic working memory task, two word-span tasks and two reading comprehension tests (narrative and expository genre) to investigate the role of semantic knowledge during comprehension. In line with previous findings, we found that younger adults used flexibly either taxonomic or thematic knowledge, whereas the older adults mainly used thematic knowledge (better preserved from age-related decline). Originally, we found that in younger adults, thematic knowledge accounted for narrative text comprehension, whereas backward span performance accounted for expository text comprehension. On the contrary, in older adults no specific predictors were found for narrative text comprehension, whereas both thematic knowledge and education level were significant predictors of expository text comprehension. Results were discussed in the light of the possible protective role of some factors such as education level and mostly, as an instance of cognitive reserve exemplified by use of thematic knowledge as a residual ability.