exhibit RIA-based polarization. This concavity arises from risk aversion, a corner- stone of decision theory, and so is more generally applicable than the experimental context (at least for small stakes). That RIA induces a risky shift then implies that group discussion tempers the risk aversion of individuals. While the economics lit- erature has found mixed results regarding whether groups are less risk averse than individuals (Sutter 2007; Baker, Laury, and Williams 2008), these experiments have involved lotteries with known probabilities whereas probability uncertainty is intrinsic to our experiment and theory and attitude change more broadly. The development of opinion network models supported by experiment will advance computational social science approaches to the dynamics of social influence. Opinion network modeling has grown rapidly in recent years reaching into physics and other disciplines (Castellano, Fortunato, and Loreto 2009). The proliferation of models, however, has far outpaced their experimental investigation. The most extensively- tested model, the Friedkin-Johnsen model, has primarily relied upon subject post- discussion ratings of interpersonal influence to estimate network weights within indi- vidual groups (Friedkin and Johnsen 2011; Dippong, Kalkhoff, and Johnsen 2017). In contrast, our quantitative testing involved network weights set by a priori topological considerations and the fitting of parameters universal to all groups, a procedure both more data-parsimonious and not dependent upon subjects’ outcome-shaped percep- tions. The ASC model describes a dual process of opinion and uncertainty change based on the greater acceptance rate of messages within one’s LOA and the decrease in LOA due to exposure to similar views. A key dynamic in the model is the ability of proximate majorities to form and persist for symmetric networks and uniform initial LOAs, thereby enabling majorities to exert outsized influence, shifting the mean even in the absence of RIA (RIA systematically skews the shift). The ASC model concep- 37