Incentives are usually expected to increase motivation and the engagement of cognitive control, and to thereby improve performance on cognitively-demanding tasks. However, a closer read of the literature suggests that incentive effects on performance can be elusive. Further, although loss incentives are common in everyday life, most laboratory studies focus on gain effects. Different theoretical perspectives offer competing predictions for the effects of loss incentives, especially in older adults: The intuitive prediction is that loss incentives should improve performance. In contrast, Socioemotional Selectivity Theory and the age-related positivity effect (Carstensen & Mikels, 2005) would predict that older adults should be largely immune to loss-incentive effects. However, Selective Engagement Theory (Hess, 2014) and the Strength and Vulnerability Integration Theory (Charles, 2010) suggest that losses might increase the ‘perceived costs’ for older adults, and thus lead to disengagement and worse performance. Moreover, most studies use changes in performance or other measures as de facto indices of motivation, rather than measuring motivation directly. To address these gaps in the literature, we examined the effects of loss incentives on measures related to subjective engagement, motivation, and meta-cognition as well as working memory. Even though loss incentive did not impact performance, our findings were most consistent with the idea that loss incentives increase the perceived demands of a task and lead to disengagement. The loss incentive also increased the absolute metacognitive accuracy. Despite the lack of age differences in some measures of the incentive effect, the post-task questionnaires suggest different reasons for arriving at these results (distraction vs de-motivation) in younger versus older adults. The results suggest that the effects (or lack thereof) of incentive on performance may reflect factors other than motivation per se.