Ability influence on effort and associated cardiovascular responses: Nocebo-Placebo evidence that perception is key.

Studies have documented the predictive utility of an integrative analysis of ability influence on effort and cardiovascular response. An assumption is that influence is driven by perception. We evaluated this altering ability perception through negative (nocebo) or positive (placebo) suggestion. Participants ingested a pill having been told it would reduce or enhance cognitive clarity. They then were presented a math task with the chance to earn an incentive if they met a low- or high performance standard. Analyses indicated higher reports of clarity during work among participants provided positive clarity instructions and a crossover clarity instruction x performance standard interaction for heart rate response. Responses were stronger for positive instruction participants when the standard was high, but stronger for negative instruction participants when it was low. Findings provide distinctive support for the assumption and suggest a fresh strategy for evaluating the impact of nocebo/placebo and other interventions on subjective experience.