 Roughly, crowds are ad-hoc and temporary social formations, chiefly characterized by automatic mimicry of one another’s emotional expression and behavior. These eventually converge, not by being centered on a common goal or by sharing collective intentions, but by so-called “psychic” or emotional “contagion” (1922: 148–159[175–191]). Typically, individuals will not even be aware of the psychodynamics at play. This makes them prone to “mass contagion” and “mass suggestion”(Stein 1922: 201–212[241–261]).