Temporal filling-in reduces attentional fluctuations in sustained visual attention

Abstract: Our capacity to maintain focus on task-relevant goals over time is constrained because attentional states wax and wane moment to moment. One theoretical account posits that temporal filling-in - filling temporal blank intervals between target stimuli - reduces attentional fluctuations to enhance sustained attention. This proposal, however, lacks direct empirical validation given the difficulty of tracking attentional fluctuations via behavioral measurements. To resolve this gap, we combined a visual timing task that assessed the behavioral benefit of temporal filling-in with electroencephalographic recordings of visual steady-state evoked potentials (SSEPs), which tracked neural responses associated with periodic attentional fluctuations entrained to the rhythmic visual sequence. Behavioral improvements in sustained attention via temporal filling-in were associated with reduced attentional fluctuations, as indexed by attenuated visual SSEP amplitudes. The findings highlight a fundamental neural mechanism whereby temporal filling-in reduces attentional fluctuations to stabilize sustained visual attention over extended periods.