Social influence occurs when an individual's thoughts or actions are affected by other people. Social influence takes many forms and can be seen in conformity, socialization, peer pressure, obedience, leadership, persuasion, sales, and marketing. Harvard psychologist, Herbert Kelman identified three broad varieties of social influence.

1. Compliance is when people appear to agree with others, but actually keep their dissenting opinions private.
2. Identification is when people are influenced by someone who is liked and respected, such as a famous celebrity or a favorite uncle.
3. Internalization is when people accept a belief or behavior and agree both publicly and privately.

Morton Deutsch and Harold Gerard described two psychological needs that lead humans to conform to the expectations of others. These include our need to be right (informational social influence), and our need to be liked (normative social influence). Informational influence is an influence to accept information from another as evidence about reality. Informational influence comes into play when people are uncertain, either because stimuli are intrinsically ambiguous or because there is social disagreement. Normative influence is an influence to conform to the positive expectations of others. In terms of Kelman's typology, normative influence leads to public compliance, whereas informational influence leads to private acceptance.

Factors