Strategies for integrating disparate social information

Abstract

Social information use is widespread in the animal kingdom, helping individuals rapidly acquire useful knowledge and adjust to novel circumstances. In humans, the highly interconnected world provides ample opportunities to benefit from social information but also requires navigating complex social environments with people holding disparate or conflicting views. It is, however, still largely unclear how people integrate information from multiple social sources that (dis)agree with them, and among each other. We address this issue in three steps. First, we present a judgement task in which participants could adjust their judgements after observing the judgements of three peers. We experimentally varied the distribution of this social information, systematically manipulating its variance (extent of agreement among peers) and its skewness (peer judgements clustering either near or far from the participant's judgement). As expected, higher variance among peers reduced their impact on behaviour. Importantly, observing a single peer confirming a participant's own judgement markedly decreased the influence of other—more distant—peers. Second, we develop a framework for modelling the cognitive processes underlying the integration of disparate social information, combining Bayesian updating with simple heuristics. Our model accurately accounts for observed adjustment strategies and reveals that people particularly heed social information that confirms personal judgements. Moreover, the model exposes strong inter-individual differences in strategy use. Third, using simulations, we explore the possible implications of the observed strategies for belief updating. These simulations show how confirmation-based weighting can hamper the influence of disparate social information, exacerbate filter bubble effects and deepen group polarization. Overall, our results clarify what aspects of the social environment are, and are not, conducive to changing people's minds.

Impact of sharing full versus averaged social information on social influence and estimation accuracy

“…In fact, in the Sorted and Unsorted treatments, the participants tend to focus their attention on the central tendency of the social information when receiving multiple estimates. This is supported by previous findings [22,29,30], and is consistent with the use of heuristic strategies under time and cognitive constraints [11][12][13].…”

“…We found that subjects follow social information substantially more when receiving the average estimate of other group members (Aggregated treatment), than when receiving a series of their individual estimates (Sorted and Unsorted treatments). Previous studies demonstrated that people are sensitive to the dispersion of estimates, and weigh social information more when the dispersion is low, a mechanism called the 'similarity effect' [22,30]. Possibly, observing the dispersion of the estimates in the Sorted and Unsorted treatments reduced the weight given to the social information as compared to the Aggregated treatment.…”

Partisan biases in social information use

“…showing ingroup and outgroup sources (Fig. S6), confirming previous observations that individuals' social information use tends to be consistent across contexts [28][29][30][31].…”

“…In four rounds, social information showed a lower vote share for the participant's preferred party, and in another four rounds, social information showed a higher vote share. To allow for a constant scope for adjustments and to control for distance effects that might influence adjustments [30,31,53], we held the difference between a participant's first prediction and social information constant at 15-18 percentage points. To enhance believability, the two remaining (filler) rounds, social information was either very close or very far from the participant's first prediction.…”

Social influence in adolescence as a double-edged sword

“…Our third experiment considers how social information shapes belief formation in a context where social values or preferences are irrelevant [31]. In such settings, social information can help individuals acquire useful knowledge [32] and make accurate decisions [33,34], but may also misinform [35], promote beliefs in conspiracy theories [36] or fuel group polarization [37].…”