Piece-Rate Time-Based Incentives Improve Sustained Attention

In two experiments, we investigated the effects of a time-based incentive on sustained attention. In both experiments, participants in an incentive condition were told the experiment duration would depend in part on their performance. Control condition participants were not given such a contingency. While both conditions displayed performance decrements (i.e., lengthening of reaction times across time), the incentivized condition demonstrated a shallower decrement. Participants in the incentive condition also reported more stable motivation and alertness across time. Finally, a combined analysis of Experiments 1 and 2 indicated that the relatively more stable alertness in the incentive conditions mediated the conditional differences in the time-on-task decrement. We concluded that (a) when faced with a difficult mental activity, people engage attention as a utility-based choice, and their motivation to perform the task is sensitive to potential rewards and (b) people will feel less mental strain in completing tasks if provided performance-contingent rewards.