Does the Understanding of Placebo Mechanisms Compensate for the Loss of Efficacy Associated With Open Label Placebo

The investigators are investigating whether, when given detailed information about underlying placebo mechanisms and pain, subjects will have a response similar to that of those subjected to a procedure in which they receive a conventional placebo treatment (associated with deception). STUDY DESIGN: This is a non-inferior parallel, controlled and randomized, single blind trial. POPULATION: The investigators will include in the study 126 subjects without known pathology. Participants will then be divided into 2 groups on a randomized basis. METHODOLOGY: Each subject will undergo three sessions of Cold Pressure Test (CPT), a cold pain stimulation method: calibration, condition of interest (conventional placebo or educated placebo) and control. The investigators' main judgment criterion is be the difference in pain intensity experienced on the visual analog scale between the CPT control and the CPT under the condition of interest. This study will allow the investigators to rule on the non-inferiority of an educated open label placebo compared to a conventional placebo in the context of an acute painful stimulation.