Pain and gain: Monetary incentive moderates pain's impact on effort-related cardiac response

Ample evidence suggests that pain leads to additional demand in cognitive functioning, presumably due to its negative affective component and its propensity to capture attention. To highlight the role of motivational incentive, two experiments tested the combined effect of pain and monetary incentive on effort-related cardiovascular response during cognitive performance. In both studies, healthy volunteers received individually adjusted painful or nonpainful thermal stimulations during a difficult cognitive task (4-back task in Experiment 1; short-term memory task in Experiment 2) and expected high (12 Swiss Francs in both experiments) or low monetary incentive (1 Swiss Franc in Experiment 1; 0.10 Swiss Francs in Experiment 2) for successful performance. Effort was primarily assessed as changes in cardiac pre-ejection period (PEP). We predicted pain to increase subjective task difficulty during cognitive performance. Moreover, according to motivational intensity theory, we expected this to increase effort only when high effort was justified by high monetary incentive. Correspondingly, pain should lead to low effort (disengagement) when monetary incentive was low. Effort in the nonpainful conditions was expected to fall in between these conditions. The results of both studies support our predictions. Our findings provide the first evidence for the moderating effect of monetary incentive on physical pain's impact on effort-related cardiovascular response. Accordingly, motivational incentives can counteract effort deficits associated with pain.