Reward and Goal Competition in Sustained Attention: Evidence from EEG and Multivariate Decoding

Sustained attention enables goal-directed behavior over extended periods but is frequently disrupted by attentional lapses. Recent accounts propose that such lapses arise from competition between task goals rather than simple failures of cognitive control. The present study examined how reward and task switching interact to shape sustained attention and its neural mechanisms. Thirty participants completed a rewarded bilateral switch Continuous Performance Task (switch-CPT) while electroencephalography (EEG) was recorded. Behaviorally, switching between task goals increased no-go errors, particularly when switching to an unrewarded goal, and these switch costs were strongest early in each block. Reward selectively reduced these errors, especially under conditions of high goal competition. Neural results revealed a dissociation across processing stages. Early spatial attention, indexed by the N2pc, was sensitive to trial type but not reliably modulated by reward or switching. In contrast, later control-related processing, indexed by the P3, was strongly influenced by both factors, with larger amplitudes for no-go trials, reduced responses under switching, and enhanced responses under reward. Oscillatory analyses showed that frontocentral theta power was greater for no-go errors than correct trials, indicating increased control demands at the time of failure, whereas alpha activity did not track attentional lapses. Multivariate pattern analysis further demonstrated that reward context could be decoded from distributed EEG activity both within and across participants. Together, these findings support a dynamic account of sustained attention in which attentional lapses emerge from goal competition and are most strongly reflected in later-stage control processes rather than early perceptual selection. Reward enhances performance by stabilizing goal engagement, particularly when competition between goals is high.