Trustees of Dartmouth College

In this experiment, the investigators study the brain pathways underlying several promising context interventions that enhance the strength of placebo effects. Specifically, the investigators examine the separate and joint effects of two of the most powerful context interventions: Social modeling-observing someone else being effectively treated-and prior treatment success or failure experiences. Participants will be randomized into 4 groups (Social modeling: observed success vs. observed failure and Conditioning: experienced success vs. experienced failure). The objectives are to investigate the placebo effect on pain relief and aversive image stimuli between and within-subjects. Each group will undergo a behavioral induction phase, fMRI placebo test phase, and an identical 3-month follow up fMRI placebo test phase. Follow-up assessment will provide some of the first evidence on predictors of the durability of placebo and context interventions.

This study examines the effects of placebo suggestions tailored to match or mismatch individual participants' motivational styles-an issue of person-situation 'fit' with important effects in public health settings, but which has been ignored in past research.

The current study probes the involvement of the opioid system in placebo effects on social pain, using the opioid antagonist naloxone. 60 participants who recently experienced an unwanted breakup will experience rejection-related stimuli and receive painful heat and pressure stimuli during fMRI scanning. Participants will be randomized to receive either a naloxone or saline nasal spray, and be informed that the spray is either saline, or an effective pain and negative emotion reducing agent.