Reward effects on cognitive functions have received a lot of scientific attention in the last years, usually finding that associating reward to a particular task ubiquitously improves performance. Yet, this work largely focused on transient reward effects using concurrent no-reward trials as the main comparison, and relatively little work has looked at potential costs of reward-based improvements. The present project aims at doing so by studying reward-context effects both during a reward manipulation and after: i) we will look for transient reward effects on no-reward trials that are presented in temporal proximity to the reward trials; ii) we will investigate the undermining effect, which posits that reward associations with a task can have negative after-effects. We will investigate the neurobiological implementation of these phenomena, as well as their conceptual link to cognitive effort and extrinsic and intrinsic motivation by using not just systematic behavioral testing but also measuring electroencephalographic (EEG), pupillometric, and cardiac activity. Jointly, these measures can make important complementary contributions to understanding reward-context effects. Together, the results of the project will significantly deepen our understanding of motivation-cognition interactions in general, and offer a wider, and potentially critical, perspective on the utility of reward manipulations beyond the mostly beneficial transient effects that are usually observed.