Social proof

Social proof, also known as informational social influence, is a psychological phenomenon which occurs in ambiguous social situations when people are unable to determine the appropriate mode of behavior. Making the assumption that surrounding people possess more knowledge about the situation, they will deem the behavior of others as appropriate or more informed.

Applications of Social Proof
Social value of unfamiliar people is ambiguous and requires a lot of effort to assess accurately. Given limited time and motivation, other people will often evaluate others based on how surrounding people behave towards them. For example, if a man is perceived to be in a company of attractive women, or is associated with them, then his perceived social value and attractiveness will be perceived to be greater. The implied cognition in this case would be "All those girls seem to really like him, there must be something about him that's high value".

If he is seen to be rejected by many women, his social value will be judged negatively. The implied cognition is then "I just saw him being rejected by many women, there is probably a good reason why they don't like him".

The concept of "Social Proof" and the fundamental attribution error can be easily exploited by persuading (or paying) attractive women to display (or at least fake) public interest in a man. Other people will attribute the women's behavior as due to the man's character and are unlikely to consider that they are interested in him due to the actual reasons (external gain).

Some men use photos of themselves surrounded by attractive women to enhance their perceived social value. The effectiveness of such tactic without support by other consistent behaviors associated with high social value is questionable.

Some nightclub and bar owners effectively employ social proof to increase their venue's popularity. This is usually done by deliberately reducing the rate at which people are allowed to enter, thus artificially causing the line to be longer. Uninformed customers might perceive the long line as a signal of the place's desirability and may wait in the line merely because "if all these people are waiting, the place must be good", while in fact the venue is mediocre and nowhere near its full capacity.

Theaters sometimes use specially planted audience members who are instructed to give ovations at pre-arranged times. Usually, these people are the one's who clap initially, and the rest of the audience follows. Such ovations may be perceived by non-expert audience members as signals of the performance's quality.

Contrary to common annoyance of canned laughter in television shows, television studios have discovered that they can increase the perceived "funniness" of a show by merely playing canned laughter at key "funny" moments. They have found that even though viewers find canned laugher highly annoying, they perceive shows that happen to use canned laughter more funny than the shows that do not use canned laughter.

Public blogs are becoming an instance of Social Proof with sometimes an eager following of widely differentiating people.

Social Proof Modifiers
Identification of the surrounding group with self

If the group people who are performing a certain behavior are perceived to belong to the same or similar group, then one is more likely to conform to the groups behavior than if one does not identify with the group.

Possession of special knowledge

If one perceives that s/he is better advised about a situation than the surrounding group, then s/he is less likely to follow the group's behavior.

Identification with Authority

If one perceives themselves as a relevant authority figure in the situation, they are less likely to follow the surrounding group's behavior. This is a combination of "Identification of the surrounding group with self" and "Possession of special knowledge". People in authority positions tend to place themselves in different categories than other people and usually they have special training or knowledge that allows them to conclude that they are better informed than the surrounding group.