Fast decisions reflect biases, slow decisions do not

TL;DR

The paper demonstrates that in large groups, early decisions are biased by initial inclinations, while later decisions tend to be more accurate, reflecting less bias and better information integration.

Contribution

It provides a mathematical framework quantifying how initial biases influence decision timing and accuracy in large groups of evidence-accumulating agents.

Findings

Early decisions reflect initial biases regardless of truth.

Later decisions are less biased and more accurate.

Bias, information quality, and decision order interact complexly.

Abstract

Decisions are often made by heterogeneous groups of individuals, each with distinct initial biases and access to information of different quality. We show that in large groups of independent agents who accumulate evidence the first to decide are those with the strongest initial biases. Their decisions align with their initial bias, regardless of the underlying truth. In contrast, agents who decide last make decisions as if they were initially unbiased, and hence make better choices. We obtain asymptotic expressions in the large population limit that quantify how agents' initial inclinations shape early decisions. Our analysis shows how bias, information quality, and decision order interact in non-trivial ways to determine the reliability of decisions in a group.