Robert Cialdini

Influence and persuasion thinker

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Robert Cialdini: Influence and persuasion thinker
Image supplied rights-cleared by the Chartered Management Institute, 2015

Professor Robert Cialdini (1945-) is a celebrated social psychologist who has undertaken extensive research on the psychology of influence, persuasion and negotiation. He is the most cited living expert in the field of persuasion research and is best known for his 1984 publication on persuasion and marketing, Influence: the psychology of persuasion which has sold over two million copies and has been translated into 27 languages.


Life and career

Cialdini undertook his undergraduate education in psychology at the University of Wisconsin and received his doctorate from the University of North Carolina. Post doctoral training from Columbia University then followed. He held Visiting Scholar appointments at Ohio State University, the Universities of California at San Diego and Santa Cruz, the Annenberg School for Communications, and at the Psychology Department and the Graduate School of Business of Stanford University.

Currently, Cialdini is the Regents' Emeritus Professor of Psychology and Marketing at Arizona State University, where he has also been named Distinguished Graduate Research Professor. He has been elected president of the US organisation, the Society of Personality and Social Psychology and is the recipient of many awards including the Distinguished Scientific Achievement Award of the Society for Consumer Psychology, the Donald T. Campbell Award for Distinguished Contributions to Social Psychology, and the Peitho Award for Distinguished Contributions to the Science of Social Influence.

Cialdini has spent his career researching the science of influence. This has earned him an international reputation as an expert in the fields of persuasion, compliance, and negotiation. Because of the global recognition of his research and his ethical business and policy applications, he is often regarded as 'the Godfather of influence’.

Key theories

The six universal principles of influence

Cialdini’s six principles of influence (also known as the six weapons of influence) were introduced in his 1984 seminal work Influence: the psychology of persuasion. Despite being published 30 years ago, the ideas in it are still valid and are used by businesses and organisations globally.

Cialdini’s interest in compliance led him to ask:

  • What are the factors that cause one person to say yes to another person?
  • Which techniques most effectively use these factors to bring about such compliance?

Cialdini's theoretical perspective is that to deal with a complex world, the human brain has evolved spontaneous or reflex responses to various phenomena.

The six principles play on primary human instincts and under normal circumstances are good traits, but they can be used against us by those who seek to exploit and influence us.

Cialdini hoped that by understanding these principles of persuasion, people would be better able to recognise situations in which they may be led to act against their will and to have the tools to resist unwanted social influence.

The six principles are:

  1. Reciprocity
  2. Commitment/consistency
  3. Social proof
  4. Authority
  5. Liking
  6. Scarcity.

Principle 1: Reciprocity

Cialdini’s first principle states that humans are hardwired to want to return favours, pay back debts and to treat others as they have been treated. In essence, we prefer to say yes. According to Cialdini, there is no human society that doesn’t practice this rule of reciprocity. It is a cultural standard that obligates us to return favours, gifts and invitations.

The reciprocity principle recognises that people feel indebted to those who do something for them. This can lead us to feel obliged to offer concessions to others if they have been offered to us, in short to reciprocate, as we feel uncomfortable being indebted to others. If a colleague, for example, has offered help to you when you were under pressure to meet a deadline then you may feel obliged to support them when they need help.

The reciprocity principle can be used for uninvited exchanges too. When this occurs the ability to freely decide is affected and people may be led to react automatically or involuntarily.

A defence against reciprocity would be to reject the initial offers or concessions. If you redefine them as tricks or ploys then you no longer feel obligated to respond reciprocally, unless you know the other person and can trust that the initial favour is given meaningfully.

Despite the strong influence that the principle may exert upon us, we have the ability to discern, adjust, or to say no in situations where we may be led to reciprocate.

Principle 2: Commitment (and consistency)

Cialdini argues that human beings have a desire to be consistent and that we also value consistency in others. Consistency is a powerful social influence which is highly valued by society. The principle of commitment declares that we have a need to be seen as consistent and to honour our commitments.

Once we have committed to something or someone, we are much more likely to go through and deliver on that commitment. So, we are far more likely to support a colleague's project proposal if we had shown interest when the idea was first raised.

To Cialdini commitments have the most authority to influence someone when they are active, public, require effort and are internally motivated or uncoerced.

To counter this principle you should not allow yourself to be pressured into accepting requests that you do not want to perform and you should disregard unjust or falsely obtained commitments. Cialdini asserts that you need to recognise the personal signals, including what he calls stomach signs and heart-of-heart signs, that can help you make the right choices.

Principle 3: Social proof

This principle is related to safety in numbers or the wisdom of crowds. Primarily Cialdini sees uncertainty as the cause of the behaviours behind this principle. When we do not know what to do, we look to others for social cues to validate our own actions.

So, for example, if a colleague is working late, then we may feel that we should also work late. Similarly, if we see that a restaurant is full of people, then we may be more likely to eat in that restaurant.

This feeling of uncertainty can be reinforced if we can relate to the people in question. So if your team members are active participants in team meetings then you may be encouraged to speak up too.

The principle of social proof leads us to believe that the greater the number of people who find an idea correct, the more the idea will seem to be correct to us.

To counter this principle it is important to recognise that the actions of others should not form the sole basis of your own actions.

Principle 4: Authority

People generally have been taught to accept and to respect authority. We want to follow the lead of experts. Often however we commit to this tendency with little or no critical thinking on our part and it is all too easy for people to confuse the symbols of authority such as titles, appearance and possessions with true substance.

This acceptance of authority - although it allows a society or culture to operate smoothly - can also lead to authority abusing its power.

A defence against this principle would be to consider your reaction to authority figures and ask yourself if the person who has triggered your respect for authority genuinely has the authority they are displaying, or merely using the symbols of that authority.

Principle 5: Liking

Cialdini argues that we are more inclined to be influenced by people we like. If we like someone then we are more likely to do what they want or ask us to do. A salesman for example will try and befriend you and get you on his side before trying to sell you something.

Cialdini cited a number of factors which influence whether one person likes another. These included attractiveness, associations, compliments, similarities, flattery, and common goals.

Persuasion experts take advantage of this principle by achieving positive associations with those they are trying to persuade, influence or manipulate. To put it bluntly, if someone wants something from you, they may compliment you.

The principle can be countered by separating the request from the requester and making decisions based on the merits of the offer, rather than on the emotional response that you may have about the requester. So, even if you like the person you must consider whether their offer is really one that is beneficial rather than being based on your connection to them.

Principle 6: Scarcity

The scarcity principle is extremely powerful and operates on the value or worth that people attach to things. In economic theory, scarcity relates to supply and demand. The less there is of something, the more valuable it can become, as more people want it. Cialdini states that humans are challenged emotionally when freedoms are threatened and scarcity can limit free choice. This may cause people to want to try and possess the item more than ever.

People are generally susceptible to some form of this principle as opportunities seem more valuable when they are less available and things which are difficult to achieve or out of reach are perceived as better.

To counter the effects of this principle we should try to step back and assess the merits of the opportunity or the value of the item in terms of why you would want it. Doing this will give an objective evaluation of its personal value rather than overvaluing it because it is scarce, or has the appearance of being scarce.

In perspective

To gather research for his book Influence: the psychology of persuasion, Cialdini observed real-life situations of persuasion by going undercover. He collected research first hand and learned the tricks mastered by used car dealerships, fund-raising organisations, and telemarketing firms. His bestselling book has brought persuasion research to the forefront of psychology. Cialdini now shares his findings with environmentalists, policymakers and business owners whilst inspiring them to use his principles of persuasion to reduce energy usage among industries and consumers.

In social settings it can often be difficult not to experience persuasion and influence. Advertising too plays on our freedoms and fears. The best defence against all of the principles therefore is to be aware of them and to try and understand when they are being used.

Further reading

Key works by Robert Cialdini


Influence: science and practice. London: Profile Books, 2012 (Illustrated edition). Previously published in 2009 by Pearson with the same title. Earlier editions were published as Influence: the psychology of persuasion. The original book was titled Influence: how and why people agree to things, published by Morrow in the United States in 1984.

With Goldstein, N. and Martin, S. Yes: 50 secrets from the science of persuasion. London: Profile Books, 2007

Pre-suasion: a revolutionary way to influence and persuade. London: Simon & Schuster, 2016

Journal articles

With Goldstein, N. and Martin, S. How to persuade people to say yes. Training Journal, May 2009, pp.36-40

With Martin, S. The power of persuasion. Training Journal, December 2006, pp.40-44

Harnessing the science of persuasion. Harvard Business Review, 79 (9) Oct 2001, pp.72-79

Sound recordings

These are available to British Library Reader Pass holders in our reading rooms in London:

Cialdini, R. and Martin, S. Small changes to make a big difference. RSA, London. 18-09-2014. Duration: 1 hr. 02 min. 00 sec.


Robert Cialdini's website


Key works by others


Muscanell, L. Guadagno, E. Murphy, S. Weapons of influence misused: a social influence analysis of why people fall prey to internet scams. Social and Personality Psychology Compass. 8 (7), pp.388-396


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