★ Items maintained in working memory (WM) can guide attention in visual search. ★ Such attentional guidance was found here to be modulated by WM load. ★ The guidance effect was present for low load but disappeared under high load. ★ The attentional guidance was unlikely to be an automatic process. ★ The attentional guidance was modulated by the cognitive resources.
An active recent line of research on working memory and attention has shown that the visual attention can be top-down guided by working memory contents. The present study examined whether the guidance effect is modulated by memory load, i.e., the amount of information maintained in working memory. In a set of three experiments, participants were asked to perform a visual search task while maintaining several objects in working memory. The memory-driven attentional guidance effect was observed in all experiments when there were spare working memory resources. When memory load was increased from one item to two items, there was no sign that the guidance effect was attenuated. When load was further increased to four items, the guidance effect disappeared completely, indicating a clear impact of memory load on attentional guidance.