Social Proof: Following the Crowd

Have You Ever?

Can you think of a time you bought something because all your friends seemed to have it? Have you ever wondered how your decisions are affected by the people around you? While we may not like to admit it, peer influences do affect humans of all ages in a serious way. Learning about the factors that drive our behaviors is a crucial part of becoming a strong decision-maker and leader.


Social conformity can be driven by normative or informational influences. Normative influences motivate people to conform for the sake of approval from others, while informational influences drive people to follow others for instructional purposes.

Definition of Social Proof

Social proof is an informational influence on human behavior: in uncertain situations where individuals are not sure how to act, they assume that other people have more knowledge or information than they do, so they look to others for cues and mirror their actions. This effect is particularly strong when the person perceives the others to be their peers or similar to themselves, and also when there are many others behaving in a certain way. Social proof is rooted in the innate human desire to belong to a social group in order to maintain one’s own self-image.

The Experiment

In 1984, psychologist Robert Cialdini outlined six principles of influence in his best-selling book Influence: The Psychology of Persuasion. These principles are liking, consistency, authority, reciprocity, scarcity, and, finally, social proof, which is also known as consensus. Working alongside psychologists Noah J. Goldstein and Vladas Griskevicius, Cialdini demonstrated social proof through an experiment involving hotel towels. Signs were placed in guests’ rooms beside their towel racks that either appealed to their desire to save the environment or evoked a social proof response, like “the majority of guests reuse their towels.” The social proof method proved to be significantly more effective, especially when tailored to match individuals’ circumstances more specifically, like “the majority of guests in this room reuse their towels.” This experiment, among others, opened the doors for further research and conversation about the use of psychological biases in policy-making and marketing.

Applying It

Six types of social proof are commonly utilized in everything from advertising to law to everyday conversation. 

  1. Campaigns often refer to expert opinions to sell a product or service. Pointing out the credentials of the person making the sale reinforces the idea that viewers should mirror this knowledgeable individual’s behavior. You may be familiar with this concept if you’ve seen any commercials for toothpaste brands that say 4 out of 5 dentists recommend the product.
  2. Similar to expert opinions, celebrity endorsements are a form of social proof. Consumers who look up to these figures and aim to emulate them in their own daily lives may be persuaded to make purchases to follow their recommendations. This sphere of marketing is ever-evolving, especially with the rise of the social media influencer in recent years. Influencers occupy a unique position that combines the elite, unattainable status of the traditional celebrity with a more relatable figure for their young supporters to look up to. From the principles of social proof, we know that this perceived sense of similarity is uniquely influential in consumer decisions.
  3. The crowd is used as a social proof tool in a wide variety of ways, all emphasizing the large number of customers who use and, therefore, approve of the product or service being sold. Some companies mark their most popular items or boast the amount of customers they’ve served. Laugh tracks even fall into this category, as hearing the imaginary masses laughing may be enough to convince you to do the same.
  4. Users often provide a source of social proof to fellow customers through product reviews, testimonials, and ratings.
  5. Consumers are typically influenced by the opinions of their friends - if people approve of their friends’ general beliefs, opinions, and choices, it makes sense that they would follow their specific product recommendations. Companies take advantage of this by offering rewards for referring a friend, or you may even see a post on your Facebook feed letting you know that your friend has liked a certain company’s page. 
  6. Certification, such as a verification on social media platforms, serves as a check of approval from the masses, much like a less formal form of “expert” credentials. 

It is important to note that social proof can lead to herd behaviors and potentially catastrophic consequences. Cialdini points to the bystander effect, as exemplified by the murder of Kitty Genovese in 1964. Intrigued by the multitude of witnesses who did not intervene in Genovese’s public murder, psychologists Bibb Latané and John Darley found that the more witnesses are present, the less likely that each one will step in to help a victim. The bystander effect illustrates the dangers of accepting and following informational cues from others who are not guaranteed to be any more informed on the situation at hand than the individual making the decision.

Social proof influences are everywhere, and it can be very difficult to avoid pressure from peers in making economic and everyday decisions alike. While this is not always a bad thing, it is important to be intentional with your choices - make sure to keep forces like social proof in mind as you make decisions with your money and otherwise.

Think Further

  1. Can you think of an example of social proof in an advertising campaign you’ve seen recently?
  2. Can you name one example of a trend popularized through social proof by social media influencers?
  3. Can you think of an event in history in which people were driven to act by social proof?


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Learn More

  1. “The 6 Principles of Persuasion by Dr. Robert Cialdini [Official Site].” INFLUENCE AT WORK, 25 June 2019,
  2. HQ, Psychology Notes, et al. “What Is the Social Proof Theory?” The Psychology Notes Headquarters, 11 Mar. 2018,
  3. Guthrie, Chris. “Influence: Principles of Influence in Negotiation.” Marquette Law Review, vol. 87, no. 4, 2004, pp. 829–837,