“Socially transmitted placebo effects”
Studies of placebo effects have demonstrated that manipulations of the interpersonal and physical treatment context can, in some cases, produce substantial effects on symptoms and behaviour and associated brain processes. Despite the robustness of these interpersonal-expectancy effects, there has been surprisingly little research demonstrating a causal link between providers’ expectations and patients’ treatment outcomes. In this study, we systematically manipulated providers’ expectations in a simulated clinical interaction involving administration of thermal pain and found that patients’ subjective experiences of pain were directly modulated by providers’ expectations of treatment success, as reflected in the patients’ subjective ratings, skin conductance responses and facial expression behaviours. Our study suggests that providers’ expectations about the efficacy of a treatment can substantially affect patients’ treatment outcomes via implicit social cues. This finding has important implications for virtually all clinical interactions between patients and providers and highlights the importance of explicit training in bedside manner when delivering information and interventions.
Access Article Here
Abstract
Medical treatments typically occur in the context of a social interaction between healthcare providers and patients. Although decades of research have demonstrated that patients’ expectations can dramatically affect treatment outcomes, less is known about the influence of providers’ expectations. Here we systematically manipulated providers’ expectations in a simulated clinical interaction involving administration of thermal pain and found that patients’ subjective experiences of pain were directly modulated by providers’ expectations of treatment success, as reflected in the patients’ subjective ratings, skin conductance responses and facial expression behaviours. The belief manipulation also affected patients’ perceptions of providers’ empathy during the pain procedure and manifested as subtle changes in providers’ facial expression behaviours during the clinical interaction. Importantly, these findings were replicated in two more independent samples. Together, our results provide evidence of a socially transmitted placebo effect, highlighting how healthcare providers’ behaviour and cognitive mindsets can affect clinical interactions.