Hypotheses
infection, depression, back pain, pain
INFECTION
Our quantitative hypotheses were based on the findings from Study 1 and Study 2. The hypotheses reported and tested here deviate slightly from our pre-registration. We had planned to test, again, for the effects of demographic variables, medical history and individual differences variables on placebo attitudes. However, given the comprehensive analyses conducted as part of Study 2, we decided to exclusively focus on the comparison of different clinical scenarios and their effects on attitude ratings pertaining to different treatment options.Clinical scenario hypothesis: Participant ratings for general treatment acceptability, personal treatment acceptability and expected treatment efficacy of different placebos will be affected by the clinical scenario presented. Participants in the infection condition (vs. depression and back pain conditions) will rate placebo treatments as less personally acceptable. Participants in the depression condition (vs infection condition and back pain conditions) will rate placebo treatments as more acceptable and effective.Treatment type hypothesis: There will be significant differences in the acceptability and effectiveness ratings for different treatment options in the hypothetical patient scenarios. Open-label placebos (where participants are fully informed about their placebo treatment) will be rated more acceptable but less effective than blinded placebos. Impure placebos like lozenges/vitamin pills/heat spray, which are treatments with known pharmacological value for some of the symptoms, but without therapeutic effects for the underlying illness, will be rated as most acceptable and effective compared to all other placebo types. Any placebo treatment will be rated as less acceptable and less effective compared to the non-placebo (i.e. active medical) treatment.