The above is sometimes given as an example of social proof in action. The subway commuters are using each others' response to the violinist in order to determine their own response to him. Without the cues that signal the violinist's quality that accompany him when performing in a concert hall, such as expensive tickets and posters, the violinist is judged by other commuters' reaction to him: as most commuters are primarily concerned with reaching their place of work, this forms the response the commuters signal to one another about the violinist.
In domains where skill is more ambiguous, one would expect the impact of social proof to be even more extreme.
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".
Similarly, a person who has been unemployed for a long time may have a hard time finding a new job - even if they are highly skilled and qualified. Potential employers attribute wrongly the person's lack of employment to the person rather than the situation. This causes the potential employers to search more intensively for flaws or other negative characteristics that are "congruent" with or explain the person's failure and to discount the applicant's virtues.
Similarly, a person who is in high demand - for example a CEO - may continue to get many attractive job offers and can as a result extract a considerable wage premium - even if his/her objective performance has been poor. When people appear successful, potential employers and others who evaluate them tend to search more intensively for virtues or positive characteristics that are "congruent" with or explain the person's success, and to ignore or underestimate the person's faults. People who experience positive social proof may also benefit from a halo effect. Other attributes are deemed to be more positive than they actually are. Additionally, the person's attributes may be viewed with a positive framing bias. For example, a person might be viewed as arrogant if they have negative social proof, and bold if they have positive social proof. (See Donald Trump).
For these reasons, social proof is important in determining a potential employer's consideration set. Social proof naturally also applies to products and is used extensively in marketing and sales. Situations that violate social proof can cause cognitive dissonance, and can cause people to have a sense of loss of control or failure of the "just world hypothesis".
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). In one scene of the movie Legally Blonde, Reese Witherspoon feigns heartbreak from a clearly unattractive male in the presence of two other women, causing the women to instantly change their behavior towards him from indifference to highly attracted.
Some men use photos of themselves surrounded by attractive women to enhance their perceived social value. The effectiveness of such tactics without support by other consistent behaviors associated with high social value is questionable.
Some nightclub and bar owners effectively employ social proof to increase the popularity of their venues. 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 ones 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.
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 group's 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.
One might perceive particular groups of others, identified by their behavior or other characteristics, to be more reliable guides to the situation than the average person. One might think truck drivers to be more frequent, and therefore more experienced diners than others, and therefore weight more heavily the number of trucks than the number of cars parked when judging the quality of a restaurant. One might identify the movement of betting odds or securities prices at certain times as revealing the preferences of "smart money" -- those more likely to be in the know.