Neural correlates of informational cascades: brain mechanisms of social influence on belief updating

Abstract

Informational cascades can occur when rationally acting individuals decide independently of their private information and follow the decisions of preceding decision-makers. In the process of updating beliefs, differences in the weighting of private and publicly available social information may modulate the probability that a cascade starts in a decisive way. By using functional magnetic resonance imaging, we examined neural activity while participants updated their beliefs based on the decisions of two fictitious stock market traders and their own private information, which led to a final decision of buying one of two stocks. Computational modeling of the behavioral data showed that a majority of participants overweighted private information. Overweighting was negatively correlated with the probability of starting an informational cascade in trials especially prone to conformity. Belief updating by private information was related to activity in the inferior frontal gyrus/anterior insula, the dorsolateral prefrontal cortex and the parietal cortex; the more a participant overweighted private information, the higher the activity in the inferior frontal gyrus/anterior insula and the lower in the parietal-temporal cortex. This study explores the neural correlates of overweighting of private information, which underlies the tendency to start an informational cascade.

Private but not social information validity modulates social conformity bias

“…How human choice behavior is influenced by the confluence of private and social information has been an active research topic in the fields of psychology and social neuroscience. Aided by formal decision theory and neuroimaging techniques, it has been shown that brain regions such as cingulate cortex (posterior cingulate cortex and dACC) and dmPFC play a critical role in conforming to social influences (Burke, Tobler, Schultz, & Baddeley, ; De Martino et al, ; Huber, Klucharev, & Rieskamp, ; Klucharev et al, ; Klucharev et al, ; Park, Goïame, O'Connor, & Dreher, ; Wu et al, ; Zaki et al, ). However, whether and how human can dynamically adjust their behavior based on the informational content remains largely unknown.…”

Informational and Normative Influences in Conformity from a Neurocomputational Perspective

“…Contrary to perceptual decision-making, this joint decision does not necessarily lead to an increased accuracy for both players and, in fact, a player with high accuracy will often suffer a decrement in joint accuracy. Consequently, in individual decisionmaking contexts where there is provision of additional social information, participants overproportionally discount social information depending on their own accuracy [41] and individual predisposition [42][43][44].…”

Neural Mechanisms for Integrating Prior Knowledge and Likelihood in Value-Based Probabilistic Inference

“…There is a growing interest in decision neuroscience in studying the effect of prior expectation on behavioral performance and the underlying neural mechanisms, ranging from perceptual decision making (Forstmann et al, 2010;Rahnev et al, 2011;Mulder et al, 2012;Kok et al, 2013), reinforcement learning (Li et al, 2011), belief updating in financial decision making in the presence of social information (Huber et al, 2014), and in trust games (Fouragnan et al, 2013). Prior expectations in most studies were manipulated by varying the reliability of cues that predicts the upcoming stimulus (Forstmann et al, 2010;Li et al, 2011;Rahnev et al, 2011;Mulder et al, 2012;Kok et al, 2013) or simply the presence or absence of prior information (Fouragnan et al, 2013).…”

“…In a financial decision task, Huber et al, (2014) found that frontoparietal regions including the inferior parietal cortex and the DLPFC update beliefs about option value in the presence of social information. To summarize, a growing body of work has begun to reveal the neural systems involved in representing prior expectations and the compu- Figure 5.…”