Lapses of sustained attention occur when goals compete: Evidences from the switch CPT

Sustained attention is the ability to maintain focus on a specific goal over time,but lapses in attention are frequent. Many theories have attributed these lapses to atransient failure of control in maintaining the goal in mind. However, these proposalshave been challenged because recent findings have shown more engagement ofcognitive control during states more prone to lapses. We hypothesized that lapses occurduring periods of high competition between goals, requiring stronger cognitive control.To test this goal-competition hypothesis, we developed a Switch-ContinuousPerformance Task in which subjects alternated task goals between blocks—eitherswitching or holding the same goal—in an effort to manipulate periods of higher andlower competition between goals. Participants viewed a bilateral display showing ascene (indoor/outdoor) and a face (male/female) on each trial. At the start of each 20-trial block, a cue instructed participants to perform either the scene task (e.g., press forfrequent indoor scenes, not infrequent outdoor scenes) or the face task (e.g., press forfrequent male faces, not infrequent female faces). Results showed more attention lapsesduring switch than repeat blocks, suggesting that lapses occur during periods of highcompetition between goals. In a second study, we monetarily rewarded performance ononly one task (scene or face) to create unequal competition between goals. We foundthat switching to an unrewarded goal—but not a rewarded goal—produced more lapses.Together, these findings support the goal-competition hypothesis as an explanation forthe occurrence of sustained attention lapses.