People assess effort in their everyday lives and such assessments may lead them to execute a task or avoid it. In this experiment, we studied effort assessments in a controlled setting using a decision-making foraging task. In this paradigm, participants could continue performing their present task or elect to perform a new task for a greater reward. We used a cognitive control demanding task (the N-Back) and physical control demanding task (the Button Pressing Task) to observe how participants assess the costs of performing a given task under specific conditions. We also asked participants to complete several self-report measures to understand how such measures may relate to effort costs. We found that participants exhibited individual differences in effort costs, and that those who had higher cognitive effort costs also had higher physical effort costs. We did not find evidence for a relationship between effort cost preferences and amotivation related self-reports (apathy and anhedonia). Thirdly, our results indicated a relationship between the Need for Cognition self-report and N-Back costs, providing evidence of convergent validity for demand-seeking behavior. This experiment yielded new insights by separating cognitive from physical effort, disentangling cost preferences from the ability to perform a task, and providing replicability in both clinical and non-clinical contexts.