Minding the load or loading the mind: The effect of manipulating working memory on coherence monitoring

Working memory plays an important role in complex cognitive tasks. For example, in the context of reading, it has been argued that working memory provides a workspace for maintenance and integration of different text units and relevant background knowledge. However, the amount of information that needs to held in mind is often at odds with the very restricted capacity traditionally posited by models of working memory. Moreover, direct evidence concerning the role of working memory during reading is ambiguous and largely based on correlational studies. To address these issues, we conducted two dual-task studies in which we manipulated working memory capacity during reading, and examined the effects of working memory capacity on the processes (rather than the products) of reading comprehension. Both experiments focused specifically on the process of coherence monitoring, a crucial component of comprehension, by comparing participants’ responses (i.e., reading times) for texts with and without inconsistencies. Moreover, in Experiment 2 we additionally examined the interaction between working memory load and availability of information by varying textual distance between inconsistent sentences. Both experiments showed that the external working memory load interfered with coherence monitoring, as reflected by reduced responses to inconsistencies. Experiment 2 further revealed that, in addition to working memory capacity, coherence monitoring is influenced by availability. Interestingly, the effect of availability was only significant in the no-load conditions, suggesting that load reduces the inconsistency effect regardless of availability. Together, these findings suggest that although readers may progress through a text relatively effortlessly by using activated portions of long-term memory, the process of coherence monitoring requires at least some working memory capacity.