The adaptive flexibility of rhythmic attentional sampling in attending to multiple targets.

Recent behavioral and neural imaging studies revealed a rhythmic sampling in the theta-band (3-8 Hz) of attention. Such observation indicates that visual attention sequentially visits attended locations rapidly and periodically to cover multiple spatial locations, which is believed driven by a general sampling mechanism with a sampling rate invariant to the number of targets. However, a general sampling mechanism with a fixed rate would lead to the consequence that it would take longer time for attention to revisit the same item when attention needs to cover more items, which could impair perceptual continuity. It is unclear whether and how the attentional sampling mechanism can flexibly adapt to varying task demand to balance between covering more items and maintaining stable perception. Here with five behavioral experiments, we investigated how the sequential sampling mechanism adapts to the need of attending to from one to four locations. With state-of-the-art analysis methods, results show clear evidence of sequential sampling in attending to multiple locations, that both theta-band oscillations and phase-shift among different locations were observed in the behavioral performance. At each location, the oscillation period increased when the attended locations increased from one to three, maintaining a relatively stable attention-dwelling time at each location. Critically, oscillation period remained essentially the same from three to four, suggesting a flexible task-driven acceleration of attentional sampling to keep the revisiting duration within a reasonable range. Thus, our results reveal that the generally stable rhythmic attention mechanism could flexibly adjust its sampling rate to accommodate increased attentional demands. (PsycInfo Database Record (c) 2023 APA, all rights reserved).