One of us or one of them? The effects of the model's and observer's characteristics on placebo analgesia induced by observational learning.

Elżbieta A Bajcar,Karolina Wiercioch-Kuzianik,Wacław M Adamczyk,Ewa Buglewicz,Przemysław Bąbel,Dominika Farley,Claus Lamm

doi:10.1371/journal.pone.0243996

Abstract

Previous studies have proved that observational learning can induce placebo analgesia, but the factors that influence observationally induced placebo analgesia have not yet been extensively examined. The primary goal of this study was to investigate the effect of information about the role that the observed person (model) plays in the experiment on the magnitude of the observationally induced placebo effect. This study also examined the contribution of the observer’s empathy, conformity and fear of pain to the placebo analgesia induced by observational learning. The effects induced in two experimental groups and one control group were compared. Participants in the experimental groups observed a model introduced as either another participant taking part in the study or a coworker of the experimenter. The model rated the intensity of pain induced by electrocutaneous stimuli preceded by color stimuli. One-half of all participants watched a model rating pain stimuli preceded by the color orange as higher than stimuli preceded by the color blue; for the other half, the ratings were the opposite. There was no observation in the control group. Subsequently, all participants received pain stimuli of the same intensity preceded by orange and blue stimuli and rated the intensity of the experienced pain. Placebo analgesia was found in both experimental groups. However, the way the observed model was introduced to participants did not affect the magnitude of placebo analgesia. Thus, the study showed that the role played by the model is not crucial for observationally induced placebo analgesia. The examined observer’s individual characteristics did not predict the magnitude of placebo effect.

Highlights

Human beings are social beings and learn from direct experience and vicariously by observing the experiences of other people [1]
Experimental studies have provided strong evidence that observational learning is one of the explanatory mechanisms of phenomena that are common in clinical settings, i.e. placebo analgesia [2,3,4,5] and nocebo hyperalgesia [3, 6,7,8]
Despite the strong evidence that observational learning can induce placebo effects, the factors influencing the magnitude of analgesia or hyperalgesia induced in this way have not yet been fully elucidated

Summary

Introduction

Human beings are social beings and learn from direct experience and vicariously by observing the experiences of other people [1]. Experimental studies have provided strong evidence that observational learning is one of the explanatory mechanisms of phenomena that are common in clinical settings, i.e. placebo analgesia [2,3,4,5] and nocebo hyperalgesia [3, 6,7,8]. It has been demonstrated that observation of a videotaped model and a live demonstrator may be effective in inducing placebo analgesia [4]. These studies focused on examining the most vivid attributes of the model, such as sex or physical presence. It has been hypothesized that a model presented as another participant would be more effective in shaping the observer’s response to a placebo and induce greater effect than a model presented as a coworker of the experimenter

Objectives

Methods

Conclusion