Social proof, also known as informational social influence, is a psychological phenomenon where people assume the actions of others reflect correct behavior for a given situation. This effect is prominent in ambiguous social situations where people are unable to determine the appropriate mode of behavior, and is driven by the assumption that surrounding people possess more knowledge about the situation.
The effects of social influence can be seen in the tendency of large groups to conform to choices which may be either correct or mistaken, a phenomenon sometimes referred to as herd behavior. Although social proof reflects a rational motive to take into account the information possessed by others, formal analysis shows that it can cause people to converge too quickly upon a single choice, so that decisions of even large groups of individuals may be grounded in very little information (see information cascades).
Social proof is a type of conformity. When a person is in a situation where they are unsure of the correct way to behave, they will often look to others for cues concerning the correct behavior. When “we conform because we believe that other’s interpretation of an ambiguous situation is more accurate than ours and will help us choose an appropriate course of action,” it is informational social influence. This is contrasted with normative social influence wherein a person conforms to be liked or accepted by others.
Social proof often leads not just to public compliance (conforming to the behavior of others publicly without necessarily believing it is correct) but private acceptance (conforming out of a genuine belief that others are correct). Social proof is more powerful when being accurate is more important and when others are perceived as especially knowledgeable.
Mechanisms
Multiple source effect
The multiple source effect occurs when people give more credence to ideas that are stated by multiple sources. This effect can be clearly seen when social proof occurs. For instance, one study observed that people who hear five positive reviews on a book as read by five different synthesized voices perceive that book more favorably than if they hear the same five reviews as read by one sythesized voice.
Uncertainty about the correct conclusion
Uncertainty is a major factor that encourages the use of social proof. One study found that when evaluating a product, consumers were more likely to incorporate the opinions of others through the use of social proof when their own experiences with the product were ambiguous, leaving uncertainty as to the correct conclusion that they should make.
Similarity to the surrounding group
Similarity also motivates the use of social proof; when a person perceives themselves as similar to the people around them, they are more likely to adopt and perceive as correct the observed behavior of these people. This has been noted in areas such as the use of laugh tracks, where participants will laugh longer and harder when they perceive the people laughing to be similar to themselves.
Research
Early research
The most famous study of social proof is Muzafer Sherif’s 1935 experiment. In this experiment subjects were placed in a dark room and asked to look at a dot of light about 15 feet away. They were then asked how much, in inches, the dot of light was moving. In reality it was not moving at all, but due to the autokinetic effect it appeared to move. How much the light appears to move varies from person to person but is generally consistent over time for each individual. A few days later a second part of the experiment was conducted. Each subject was paired with two other subjects and asked to give their estimate of how much the light was moving out loud. Even though the subjects had previously given different estimates, the groups would come to a common estimate. To rule out the possibility that the subjects were simply giving the group answer to avoid looking foolish while still believing their original estimate was correct, Sherif had the subjects judge the lights again by themselves after doing so in the group. They maintained the group’s judgment. Because the movement of the light is ambiguous the participants were relying on each other to define reality.
Another study looked at informational social influence in eyewitness identification. Subjects were shown a slide of the “perpetrator”. They were then shown a slide of a line-up of four men, one of whom was the perpetrator they had seen, and were asked to pick him out. The task was made difficult to the point of ambiguity by presenting the slides very quickly. The task was done in a group that consisted of one actual subject and three confederates (a person acting as a subject but actually working for the experimenter). The confederates answered first and all three gave the same wrong answer. In a high-importance condition of the experiment subjects were told that they were participating in a real test of eyewitness identification ability that would be used by police departments and courts, and their scores would establish the norm for performance. In a low-importance condition subjects were told that the slide task was still being developed and that the experimenters had no idea what the norm for performance was—they were just looking for useful hints to improve the task. It was found that when subjects thought the task was of high importance they were more likely to conform, giving the confederate’s wrong answer 51% of the time as opposed to 35% of the time in the low-importance condition.
Cultural effects on social proof
The strength of social proof also varies across different cultures. For instance, studies have shown that subjects in collectivist cultures conform to others’ social proof more often than those in individualist cultures.
Copycat suicides
Social proof has been proposed as an explanation for Copycat suicide, where suicide rates increase following media publication about suicides. One study using agent-based modeling showed that copycat suicides are more likely when there are similarities between the person involved in the publicized suicide and the potential copycats.
Examples
In social interactions
The 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 seen to be in the company of attractive women, or is associated with them, then his 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 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.
In employment
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.
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”.
In entertainment
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 laughter highly annoying, they perceive shows that happen to use canned laughter more funny than the shows that do not use canned laughter.
Modifiers
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.
“Smart money”
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 drivers than others, and therefore weigh 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.