Abstract: Many of the methodological tools used to assess cognitive effort have lacked the precision needed to index the cost of mental labor. Furthermore, although prior work suggests strong associations between personality traits and motivation and achievement, it is unclear if such individual differences can explain underlying differences in the propensity to engage in cognitive effort. Therefore, the main goal of the present study was to measure the subjective value of motivational incentives and their subsequent impact on task performance in a manner that was sensitive to individual differences. To accomplish this goal, we developed a novel task paradigm that combined economic decision-making with an effortful cued task-switching paradigm, in which participants were required to respond fast and accurately to presented stimuli while integrating the diverse incentive types (liquids, money) offered on each trial. The results demonstrate that as motivational value increased, task performance improved, suggesting greater exertion of cognitive effort; however, there were no reliable associations between personality traits and task performance.