Ranking-based Social Influence Produces Lock-in

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Abstract: Individual choices are influenced by the past 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 qualitatively superior or inherently more appealing alternative. A necessary condition for lock-in is that influence is so strong that the inferior option is chosen at least as frequently as its relative popularity. Yet many canonical experiments that demonstrate the existence of social influence do not satisfy the lock-in condition, suggesting that many systems may self-correct over time. We theoretically identify a property that makes it easier to satisfy the lock-in condition, namely when choices are informed by popularity ranks rather than the number or proportion of prior choices by others. We demonstrate the existence of ranking effects in several recent experiments, and show that lock-in occurs when the ranking effect is sufficiently large to overcome inherent differences in appeal between options. Our results reconcile conflicting past empirical evidence and link a prevalent social influence mechanism with the possibility of lock-in.