CONCEPT
Critical Mass (Rogers)
The threshold at which enough members of a social system have adopted an innovation that further adoption becomes self-sustaining — and the point beyond which voluntary choice collapses into compulsory adaptation.
Rogers borrowed critical mass from nuclear physics to describe the threshold effect observed across diffusion studies: below a certain level of adoption, the process proceeds slowly and may stall or reverse; above it, adoption accelerates rapidly and becomes, in practical terms, irreversible. Critical mass is not a fixed number but a function of the social system's structure, the innovation's network externalities, and the communication dynamics through which information flows. Its most important implication is political: crossing the threshold transforms the social dynamics of adoption from voluntary choice into compulsory adaptation. The last farmer to adopt hybrid seed adopts not because the innovation is better, but because the market has been restructured around it.
In The You On AI Field Guide
Critical mass operates with particular force in interactive innovations — telephones, email, messaging platforms — whose value depends on the number of others who have adopted. The first telephone was useless because there was no one to call; each subsequent adoption