Relative contribution of vocabulary knowledge and working memory span to elaborative inferences in reading

Eye fixations were assessed during the reading of continuation sentences confirming inferences suggested by a preceding context sentence. In multiple regression analysis, individual differences in available prior vocabulary knowledge, working memory span, and speed of access to prior word knowledge served as predictors of eye fixations. Accessibility speed was associated with first-fixation time and gaze duration across all sentence regions. Vocabulary knowledge was associated with reduced looks-back from the target word that represented the inference in the continuation sentence. Working memory span was associated with reduced gaze duration and looks-back from the final word of the continuation sentence. It is concluded that accessibility is a general reading efficiency factor. In contrast, both vocabulary knowledge and working memory make specific, although delayed, contributions to inferences: Vocabulary knowledge facilitates the selection of linguistic representations for the inference; working memory helps to integrate meanings in situation model construction of the inference.