Contagion theory is about how emotions and impulses spread quickly in a crowd, causing individuals to lose personal restraint and act on feelings they might suppress when alone. In a group, arousal is shared, and private tendencies surface and intensify through this emotional contagion, making it feel like those underlying urges are being released. By contrast, convergence theory says crowds form because people with similar motives come together, so behavior reflects preexisting dispositions rather than a release of hidden impulses. Emergent norm theory focuses on how new norms arise to guide collective action, not on unleashing latent tendencies. So the description of releasing underlying personal tendencies best aligns with contagion theory.

Internalization is about norms becoming part of who you are, so you follow them because they feel like your own standards, not just because you’re told to. That makes the description that emphasizes acceptance of norms as part of one’s identity the best fit, since it captures the integration of norms into one’s self-concept. The idea of conscious adoption suggests a deliberate choice that may not fully reflect the deepest internal integration. External controls, like formal sanctions or shaming, influence behavior from the outside and don’t describe norms being taken into the self.

Power is the capacity to influence or control the actions of others, even when they do not recognize or accept the authority of the person or institution involved. It doesn't depend on social legitimacy; it can come from resources, expertise, position in networks, or persuasive ability. That makes it the best fit for influence that occurs regardless of whether authority is socially recognized. By contrast, legitimate authority, charismatic authority, and legal-rational authority all rely on some form of social acceptance or placement within a system—recognition that the person or office has the right to command—so they aren’t about influence independent of that recognition.

When a movement becomes an accepted and institutionalized part of society, its ideas, aims, and practices are woven into the functioning of major social institutions—laws, policies, education, government agencies, and even everyday norms. This means the changes it advocates persist through rules and structures, not just through ongoing activism. The movement’s goals are reflected in formal mechanisms: passed legislation, established organizations, official guidelines, and widespread acceptance within institutions, so the shift becomes a lasting part of how society operates. That process—embedding a movement into the backbone of society—is what we call institutional change. For context, other terms describe different things. Urbanization is about people moving into cities and the growth of urban areas; gossip refers to informal, often casual sharing of information; public opinion is the collective attitudes of people, which can influence but isn’t the same as formalizing changes into institutions.