OLP rationale
OLP
The OLP rationale was given in the same way as in our experimental OLP laboratory studyNext, participants were shown two videos that reiterated the delivered information. In the first video, a post-doctoral fellow (AW) gave a lecture about OLPs entailing the same four key points as described above. In the second video, a professor of psychology (CH) outlined the clinical relevance of placebo research. These two experts were introduced as advanced researchers with a high reputation in the field of placebo research. The total duration of these two videos was about 10 min.Providing the OLP rationale took approximately 30 min. In order to standardize the interaction between experimenter and participant, a semistructured script was used. The experimenters comprised three female psychology students, each wearing a white laboratory coat. The experimenters were instructed to be supportive and confident. Experimenters were also instructed on how to answer questions and to openly address any doubts the participants may have. To minimize any experimenter effects, all three experimenters were trained extensively, practiced the experimental procedure several times under supervision and provided feedback to each other.