Working memory capacity and time course of predictive inferences

A naming task assessed activation of inference concepts during reading. A p redicting, or a control, context sentence was followed by a target word to be named, which represented the predicted event or an inconsistent event. T he interval between the end of the context and the onset of the target word varied between 50 and 1050msec. Individual differences in working memory c apacity were assessed by the reading span task. As reflected by facilitatio n in naming latencies in the predicting condition, relative to the control condition, (a) inferences were not made within the first 50msec after the c ontext, regardless of reading span; (b) only the high-span participants dre w inferences within a 550-msec interval; and, (c) both the high-and the low -span participants generated them within a 1050-msec interval. These result s indicate that high working memory capacity accelerates the time course of predictive inferences, although they do not become automatic. We propose t hat this effect occurs because these inferences involve time-consuming elab orations that place demands on the effortful and limited resources of worki ng memory. Deficiencies in word knowledge, speed of lexical access, or comp rehension of explicit information do not account for low-span readers' diff iculties in generating predictive inferences.