To date, very little is known about the mechanisms of open-label placebo treatment and there is a lack in highly controlled experimental designs. Therefore, the planned project will test well-established explanatory models of (deceptive) placebo, i.e., (1) expectancy, (2) meaning response, in an open-label placebo design, investigating their influence on placebo analgesia.

The current project will consist of one experimental study and one qualitative study:

1. the effects of open-label, and deceptive placebo administration on placebo analgesia will be directly compared when both groups have a comparable expectancy-inducing scientific rationale;
2. subjective meaning models will be assessed by comparing subjective narratives of the placebo effect in open-label and deceptive placebo groups in a nested qualitative study.

The experimental study will be a randomized experiment with healthy subjects (N=120), and pain will be induced using a standardized heat pain paradigm (Medoc, Ramatishai, Israel; thermo-sensory analyzer (TSA)-II). Effects of the experimental conditions will be assessed both objectively (i.e. heat pain threshold and tolerance) and subjectively (i.e. subjective pain ratings, pain intensity and unpleasantness). Furthermore, investigators will randomly select 30 participants to take part in a nested qualitative study in order to qualitatively assess the meaning response by comparing subjective narratives of the placebo effect in the open-label and deceptive placebo groups, as well as in the control group.

Inclusion Criteria:

• Healthy male and female adults aged 18-65
• Healthy by self-report statement, thus no known current or chronic somatic diseases or psychiatric disorders
• Right-handedness (Oldfield, 1971),
• Willing to participate in study

Exclusion Criteria:

• Medicine or Psychology Students
• Any acute or chronic disease (chronic pain, hypertension, heart disease, renal disease, liver disease, diabetes) as well as skin pathologies, neuropathies or nerve entrapment symptoms, sensory abnormalities affecting the tactile or thermal modality
• Current medications (psychoactive medication, narcotics, intake of analgesics) or being currently in psychological or psychiatric treatment
• Insufficient German language skills to understand the instructions
• Previous participation in studies using pain assessment (threshold and tolerance) with Peltier Devices
• Daily consumption of more than three alcoholic standard beverages per day (a standard alcoholic beverage is defined as either 3dl beer or 1 dl wine or 2cl spirits)
• Current or regular drug consumption (THC, cocaine, heroin, etc.)