Enhanced or distorted wisdom of crowds? An agent-based model of opinion formation under social influence

TL;DR

This paper uses an agent-based model to explore how social influence affects collective opinion accuracy, revealing that social influence often worsens the wisdom of crowds rather than improving it.

Contribution

It introduces a novel agent-based model analyzing the impact of social influence regimes on collective opinion accuracy, highlighting conditions where wisdom of crowds fails.

Findings

Social influence often reduces the accuracy of collective opinions.

Agents tend to converge to opinions farther from the truth under social influence.

Full information regimes can sometimes improve or worsen collective accuracy.

Abstract

We propose an agent-based model of collective opinion formation to study the wisdom of crowds under social influence. The opinion of an agent is a continuous positive value, denoting its subjective answer to a factual question. The wisdom of crowds states that the average of all opinions is close to the truth, i.e. the correct answer. But if agents have the chance to adjust their opinion in response to the opinions of others, this effect can be destroyed. Our model investigates this scenario by evaluating two competing effects: (i) agents tend to keep their own opinion (individual conviction $\beta$), (ii) they tend to adjust their opinion if they have information about the opinions of others (social influence $\alpha$). For the latter, two different regimes (full information vs. aggregated information) are compared. Our simulations show that social influence only in rare cases enhances the wisdom of crowds. Most often, we find that agents converge to a collective opinion that is even farther away from the true answer. So, under social influence the wisdom of crowds can be systematically wrong.