Firms and other economic actors do not choose their courses of action in isolation: they monitor each other, and make inferences about the uncertain situation they face by noting the success or failure of others' strategies. When this leads to diversity to firms selecting different strategies and coming to occupy different "niches" -a stable market structure can result. But if firms imitate, each choosing the same strategy, potentially disastrous "crowding" can occur.

Donald MacKenzie, An Engine, Not a Camera, loc. 1227