Caildini’s Six Principles of Influence

Robert Cialdini, a Regents Professor Emeritus in Psychology and Marketing at Arizona State University, is a world-wide expert in the fields of influence, persuasion, and compliance.  With over 35 years of scientific research focusing on the art of influence and why people comply with requests,  Dr. Cialdini has gained an international reputation as the “Godfather of Influence.”

His book Influence: The Psychology of Persuasion  (Links to an external site.)(first published in 1984) is regarded as the seminal (i.e., groundbreaking) publication on Marketing and has significantly influenced what we know and understand about the concept of persuasion today. In this book, Cialdini highlighted what he refers to as the Six Principles of Influence: reciprocity, commitment/consistency, social proof, authority, liking, and scarcity. If you’ve taken any courses focusing on Persuasion, Marketing, or Psychology, you may already be familiar with these principles. However, even if you’ve never heard of Caildini’s principles, I guarantee each and every one of you has encountered them – and even used them yourselves from time to time in an attempt to persuade others.

Cialdini’s 6 Principles of Influence are reviewed in the next section.


Caildini’s Six Principles of Influence

  1. Reciprocity

How reciprocity is used: Helping someone and/or offering a favor so they feel obligated to “return the favor” (by complying with your request).

Why reciprocity works: Many people have a fundamental need or obligation to repay others and/or return favors  Similar to Andy Bernard in The Office (see example below), we don’t like to feel indebted to others.

In sum, here’s why reciprocity works in Cialdini’s own words: “because there is a general distaste for those who take and make no effort to give in return, we will often go to great lengths to avoid being considered a moocher, ingrate, or freeloader” (Cialdini, 1984, p. 206).

Examples of reciprocity (offline/face-to-face):  Salespeople at the mall and in department stores rely heavily on reciprocity.  By approaching shoppers and offering samples of their products, they hope that the shoppers will feel “obligated” to return their kindness and make a purchase. In fact, many people refuse “free samples” and “free trials” simply because they do not want to feel pressure to comply with a pushy salesperson’s request to buy something.

We also use the principle of reciprocity with our family members, friends, and co-workers. If you’re a fan of the TV show The Office, you might be familiar with the episode where Dwight does all these unexpected favors for everyone in the office, such as bringing them bagels for breakfast and cleaning out the refrigerator in the break room. As people tell him “Thank you,” he keeps replying with “No worries. You can just owe me!”  His goal is to make everyone in the office to feel indebted to him so that he can “cash in” their favors later by demanding that they help him get Jim fired.

Much to Dwight’s annoyance, one member of the office–Andy Bernard–isn’t comfortable just accepting his random acts of kindness.  Thus, he immediately returns Dwight’s favors by polishing his shoes and buying the entire office lunch.  Later in the episode, the rest of the office also “reciprocates” Dwight’s generosity by giving him a Starbucks gift card.  Overall, then, the principle of reciprocity worked–just not in the way Dwight had imagined.

Examples of reciprocity (online): The principle of reciprocity is a little tricky online. Recall that one of the main reasons reciprocity works is because people do not want to be viewed as a “free loader” or a “mooch” who takes from others without attempting to repay them. The ability to stay anonymous in online contexts allows people to accept certain perks and not return the favor without judgment from others.

For example, you can enjoy “Spotify’s 30-Day Free Trial Offer” and cancel it online before it charges your card and not feel an ounce of obligation or guilt.  Now imagine you could only get the 30-Day trial by speaking to a customer service representative on the phone, and–if you did not want to purchase the subscription once the trial ended–you had to call the same representative back after 30 days to cancel the trial.  For most people, it would be more difficult to cancel the trial if we had to speak to a person (and some people would likely avoid getting the trial altogether). The ability to sign up for and cancel “free trials” and other “free” samples/gifts anonymously online allows us to sidestep the sense of obligation and feelings of indebtedness that usually accompany the principle of reciprocity.


  1. Commitment/Consistency

How commitment/consistency is used: The commitment/consistency principle involves getting people to agree with an idea or commit to a goal so that they are more likely to follow-through on later requests.

Why commitment/consistency works: People prefer to maintain consistency with things they have previously said and done.  Once people have publicly committed to a belief, attitude, or behavior, it becomes a part of their self-image.  Therefore, they are likely to follow through on that commitment because they do not want to be viewed as a “flake” or as “wishy-washy.”


  1. Social Proof

How social proof is used: The social proof principle involves demonstrating that a behavior (or an idea, product, etc.) is liked, recommended, or endorsed by others so that people will view it as the “correct” behavior.

Why social proof works: People tend to trust in things that are popular in general (“everyone’s doing it” mentality) and/or that are endorsed by people we like and trust (e.g., friends, online influencers, celebrities, etc.).  Many people have a need or a desire to behave in socially acceptable ways; thus, they pay attention to what others are doing for “proof” regarding what behaviors are appropriate.  In short, people do not want to be the “odd one out.”

Though the principle of social proof is based on the idea that there’s “safety in numbers,” the size of the crowd is not the only way individuals evaluate a behavior as correct or appropriate.  In some cases, the specific people who are promoting or endorsing a product, behavior, or idea are just as important as (or even more important than) the number.  For instance, our friends typically have more influence on our behavior than people we do not know very well. Additionally, endorsements made by celebrities and online “influencers” are often valued over those made by those of lesser fame and status.

Examples of social proof: Social proof is one of the most well-known and most common principles of influence.  If you’ve ever started watching a new TV show because a few of your friends spoke highly of it, read reviews on Amazon before making a purchase, or decided to check out a new brewery in town because “everyone’s talking about it,” then you have been swayed by social proof.

One of the main areas where we see social proof in action today is in Influencer Marketing.


Social Proof and Online Influencers 

  1. Authority

How authority is used: The authority principle involves using an authority figure–such doctors or experts in a given field–to endorse a behavior (or an idea, product, etc.) so that people perceive the persuasive message as credible and trustworthy.

Why authority works: People generally trust and respect authority figures, so they are likely to feel comfortable engaging in behaviors and accepting ideas that they endorse.  In fact, due to the tendency to obey authority figures, many people will comply with requests made by those in power even if they are not necessarily comfortable with the request.

The principle of authority may seem similar to social proof, but it’s based primarily on perceived expertise, power, and credibility – not on the number of people endorsing a product and/or their perceived social status.


  1. Liking

How liking is used: The liking principle involves establishing a rapport with people and getting them to like you so that they are more likely to comply with a request.  A key element of liking is similarity; that is, we are often more easily persuaded by people we can relate to in terms of beliefs/opinions, background and experiences, hobbies, personality, and lifestyle. Additionally, persuaders will often compliment the people they are attempting to persuade in order to increase liking.

Why liking works: People are more likely to trust and be more receptive to people they like than people they do not like (or people they do not know well enough to form an opinion about).  The persuader’s physical attractiveness also plays a role in the principle of liking.  Because attractive individuals are often automatically viewed as kind, honest, and intelligent, people tend to trust and like them more easily/quickly than those who are less attractive.


  1. Scarcity 

The scarcity principle involves emphasizing that something (a product, service, opportunity) is in limited supply or only available for a limited amount of time so that people will “act quickly” and comply with a request.

Why scarcity works: The fewer there are of something (and the less time there is to obtain it), the more we want it. In other words, when there is limited availability of a product, we tend to need and value it more.

Basically, the principle of scarcity creates the impression that we are losing something, which is a powerful motivator for humans.  As Caildini (1984) noted, “The idea of potential loss plays a large role in human decision making. In fact, people seem to be more motivated by the thought of losing something than by the thought of gaining something of equal value” (p. 365).

Examples of scarcity: You’ve heard it all: Limited time offer! Act now! While supplies last!

Travel sites love using the scarcity principle:



  1. Unity

In his 2016 book, Pre-Suasion: A Revolutionary Way to Influence and Persuade,  (Links to an external site.)Dr. Cialdini added a 7th principle to his typology: UNITY.