社會影響是指一個人的情緒、觀點或行為有意或無意地受到他人的影響。社會影響有多種形式，可以從從眾、社會化、同輩壓力、服從、領導、說服、銷售和市場營銷中看到。1958年，哈佛大學心理學家赫伯特·凱爾曼發現了三種廣泛的社會影響順從是指人們表面上同意別人的觀點，但實際上不公開自己的不同意見。身份認同是指人們受到喜歡和尊重的人的影響，比如名人。內部化是指人們接受一種信仰或行為，并在公開場合和私下里達成一致。Morton Deutsch和Harold Gerard描述了兩種導致人類遵從他人期望的心理需求。這些包括我們需要正確(信息社會影響)和我們需要被喜歡(規范的社會影響)。[3]信息影響(或社會證明)是一種接受來自他人的信息作為事實證據的影響。當人們不確定的時候，信息影響就會發揮作用，要么是因為刺激本身是模糊的，要么是因為存在社會分歧。規范性影響是一種順應他人積極期望的影響。在Kelman的類型學中，規范性影響導致公共服從，而信息性影響導致私人接受。

Social influence occurs when a person's emotions, opinions or behaviors are affected by others intentionally or unintentionally.[1] Social influence takes many forms and can be seen in conformity, socialization, peer pressure, obedience, leadership, persuasion, sales, and marketing. In 1958, Harvard psychologist Herbert Kelman identified three broad varieties of social influence.[2] Compliance is when people appear to agree with others but actually keep their dissenting opinions private. Identification is when people are influenced by someone who is liked and respected, such as a famous celebrity. 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).[3] Informational influence (or social proof) 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.[2]