A Transcranial Magnetic Stimulation Investigation of the Role of the Temporal Parietal Junction in Social Influence and Risky Decision Making

Abstract

The process by which individuals make decisions has important implications in a number of fields, such as economics and psychology. Several factors influence choice including characteristics of the decision itself, as well as environmental and individual factors. One source of deviation from typical decision-making is social influence, especially in decisions involving risk. The current study investigated the role of the rTPJ on social influence and risky decision-making using inhibitory cTBS. We hypothesized that susceptibility to social influence on risk-taking in an economic decision-making task would decrease following stimulation to the rTPJ, while risk-taking in the absence of social information should be unaffected. However, our results did not illustrate a significant relationship between stimulation and susceptibility to social influence, such that social influence increased risk-taking behavior. This may indicate that while the rTPJ is involved in decision-making in a social context, other brain regions are responsible for the incorporation of social information into economic risk-taking. However, it is likely that computations of risk were inhibited through suppression of the nearby posterior parietal cortex. This is corroborated by trending effects of increased risk-taking and slower reaction times on the decision-making task, and the absence of deficits on a theory of mind task.