The effect of cue probe interval on internal attention: Evidence from event-related potentials

Compelling evidence indicated shared cognitive mechanisms underpinning attention in both the external and internal domains. Typically, both external attention and internal attention are vulnerable to biases from intended goals and stimulus features. However, it is still unclear whether the temporal characteristics of the relationship between goal-directed and stimulus-driven external attention could be observed in internal attention. This study aimed to fill this gap by examining whether the lengths of time interval before a recalling probe influenced goal-directed and stimulus-driven internal attention. We manipulated the cue probe interval (CPI) before the probe in a working memory change detection task with a retrospective cue. In addition to behavioral performance, we also traced two electrophysiological signals of the event-related potential (ERP) components of N450 and P300 to represent goal-directed and stimulus-driven internal attention respectively. The results suggested that CPI modulated goal-directed attention with more pronounced N450 amplitudes when CPI was 2000 ms than those when CPI was 500 ms during the informative condition. Meanwhile, more pronounced P300 amplitudes were observed when CPI was 500 ms than those when CPI was 2000 ms for both the matching and nonmatching conditions. Such results lead to the conclusion that internal attention was goal-directed when CPI was as long as 2000 ms, whereas stimulus-driven when CPI is as short as 500 ms. Findings from this study contribute to the common points shared between internal and external attention.