Pain is an evolutionary alarm signal that captures attention and, therefore, interferes with cognitive functioning. Nevertheless, there is substantial variability between and within persons in how pain affects performance on cognitive tasks, that is difficult to explain by available theoretical models. Often ignored in these models is that human beings are not passive receivers of internal and external stimuli, but active decision-makers. That is, based upon a continuous and dynamic weighting of possible costs (expected effort) and benefits (anticipated reward), they decide to either exert effort or not in function of ongoing goal pursuit. The current project aims examining how pain influences this cost-benefit analysis, effort-based decision-making processes and, consequently, fluctuations in cognitive task performance. For this purpose, knowledge from research domains on pain-cognition interaction, motivation, and effort-based decision-making, are integrated into a novel theoretical framework, generating new hypotheses, and explaining inconsistent findings in previous research. Behavioral, electrophysiological, and psychophysiological methods are adopted to allow a comprehensive view on how effort-based processes during cognitive task performance are affected by acute (experimental) and chronic pain. It is expected that the project will significantly advance understanding of pain-related cognitive interference and will provide new routes for interventions.