Role of the executive function in the relationship between verbal working memory and long-term information

It is well known that long-term information contributes to verbal working memory. Although the phonological loop is assumed to have an important role in verbal working memory, the processing of long-term information is supposed to occur in another system, and the executive function is presumably involved in this process. Long-term information that affects verbal working memory can be divided into two types of representations: semantic information and long-term phonological knowledge. We used a dual-task method to investigate the role of the executive function in the processing of these two types of representation. We focused on the concreteness effect and the frequency effect, which are assumed to reflect semantic information and long-term phonological knowledge, respectively. The concreteness effect was banished when the executive function was disrupted by focusing on verbal semantic features. The frequency effect remained intact when the executive function was disrupted, while the burden on the phonological loop caused the effect to be decreased. We concluded that the executive function plays a crucial role in the processing of verbal semantic information, but not in the processing of long-term phonological knowledge.