# The marginal majority effect: When social influence produces lock-in

## TL;DR

People often choose popular options over better ones when influenced by others, leading to a phenomenon called the marginal majority effect.

## Contribution

The paper introduces the 'marginal majority effect' as a new behavioral phenomenon that explains social lock-in.

## Key findings

- The marginal majority effect causes a sudden increase in popularity when an option surpasses a competitor.
- Lock-in occurs when the effect outweighs the quality of the options.
- This effect reconciles conflicting evidence on social influence and lock-in.

## Abstract

People are influenced by the choices of others, a phenomenon observed across contexts in the social and behavioral sciences. Social influence can lock in an initial popularity advantage of an option over a higher quality alternative. Yet, several experiments designed to enable social influence have found that social systems self-correct rather than lock in. Here, we identify a behavioral phenomenon that makes inferior lock-in possible, which we call the “marginal majority effect”: a discontinuous increase in the choice probability of an option as its popularity exceeds that of a competing option. We demonstrate the existence of a marginal majority effect in several recent experiments and show that lock-in always occurs when the effect is large enough to offset the quality effect on choice but rarely otherwise. Our results reconcile conflicting past empirical evidence and connect a behavioral phenomenon to the possibility of social lock-in.

Popularity trumps quality when people are influenced by popularity ranks rather than counts.