Lauren C. Howe, J. Parker Goyer, and Alia J. Crum
Health Psychology, 36(11), 1074-1082.
Objective: Research on placebo/nocebo effects suggests that expectations can influence treatment outcomes, but placebo/nocebo effects are not always evident. This research demonstrates that a provider’s social behavior moderates the effect of expectations on physiological outcomes.
Methods: After inducing an allergic reaction in participants through a histamine skin prick test, a health care provider administered a cream with no active ingredients and set either positive expectations (cream will reduce reaction) or negative expectations (cream will increase reaction). The provider demonstrated either high or low warmth, or either high or low competence.
Results: The impact of expectations on allergic response was enhanced when the provider acted both warmer and more competent and negated when the provider acted colder and less competent.
Conclusion: This study suggests that placebo effects should be construed not as a nuisance variable with mysterious impact but instead as a psychological phenomenon that can be understood and harnessed to improve treatment outcomes.
Link to the pdf is here.