Getting to the source of the illusion of consensus

Abstract

Consensus between informants is a valuable cue to a claim’s epistemic value, wheninformants’ beliefs are developed independently of each other. Recent work (Yousif et al., 2019) described an illusion of consensus such that people did not generally discriminate between the epistemic warrant of true consensus, where a majority claim is supported by multiple independent sources, and false consensus arising from repeated claims from the same sources. We re-examined this issue in two ways. First, a Bayesian re-analysis of the Yousif et al. (2019) results found that the evidence for the illusion of consensus was not as strong as originally claimed. Second, three experiments tested the hypothesis that the illusion of consensus only arises when people are unsure about the independence of the primary sources on which informant claims are based. When steps were taken to highlight the independence between data sources in the true consensus conditions, and confidence ina claim was measured against a no consensus baseline (where there was an equal number of reports supporting and opposing a claim), we eliminated the illusion of consensus. Under these conditions, more weight was given to claims based on true consensus than false consensus. These findings have implications for how people evaluate consensus and reason with dependent information. Our findings are relevant to the contemporary media context, where the (in)dependence of information sources can be obscured and lead to the appropriation of erroneous beliefs.

Sensitivity to Evidential Dependencies in Judgments Under Uncertainty

“…To return to our initial example, three seemingly independent tweets from independent news sources may ultimately share common data. Hence, the adaptive learner may adjust for assumed dependence, even in experimental contexts like ours where the instructions and experimental procedure were intended to convey independence (Connor Desai, Xie, & Hayes, 2022).…”