Σεμινάριο: "Self-reinforcing popularity and lock-in"

ΚΥΚΛΟΣ ΣΕΜΙΝΑΡΙΩΝ ΣΤΑΤΙΣΤΙΚΗΣ 2025-2026

Ομιλητής: Alexandros Gelastopoulos, Research fellow, Institute for Advanced Studies in Toulouse

Αμφιθέατρο Τροίας

ΠΕΡΙΛΗΨΗ

Whether it is about choosing a party to vote for, deciding whether to adopt an innovation, selecting music to listen to, or which social media application to use, people tend to select options that many other people have selected before them. This creates a feedback loop in which popular options tend to become even more popular, potentially leading suboptimal options to become dominant while inhibiting the adoption of better alternatives, a phenomenon known as “lock-in”. Although such rich-get-richer dynamics and the occurrence of lock-in have traditionally been assumed to be ubiquitous in the social world, the experimental evidence is mixed, suggesting that at least in certain settings the macro-consequences of social influence might be much more limited than previously thought. 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.