Persuasion: The Psychology of Influence

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Persuasion: The Psychology of Influence

Why do we follow the majority? Is it because they are more right? No, but they are stronger. (Blaise Pascal, Pensées, 1660)

Reason is never aware of its hidden assumptions. (L.L. Whyte, The Unconscious Before Freud, 1962)

The soft spoken salesman strikes the hardest bargain. (Anon)

A salesman is someone who it is always a pleasure to bid goodbye to. (Anon)


In a very important book, the American psychologist Cialdini (2007) proposes six key principles of persuasion, which can be employed to influence others. His work has been among the most influential in the whole of social psychology.

1 Reciprocity. When we are given something by another person, or treated well, we feel obliged to reciprocate the kind behaviour shown to us. We reciprocate in kind: you send me a Christmas card and I send another back; you buy me a drink and I ’return the favour’. You spend money on me and I give it back in some way. All human societies subscribe to this rule. As humans we do not feel happy being indebted to someone and so offer something in return for what others have provided us with. Therefore, in order to persuade another person to do something for you, you should consider doing something for them. The whole psychology of the ’free gift’, the coupon and the ’taster’ is the psychology of reciprocation.

The principle is: people (nearly always) repay in kind.

2 Commitment and Consistency. We (particularly in the West) have a drive to be consistent. When we make a commitment to do something, we experience personal and interpersonal pressure to behave as we have suggested that we will. Inconsistency is frowned upon and considered to be an undesirable personality trait by (Western) society and so is avoided. Making a small commitment can therefore result in significant behavioural changes. It is for this reason that politicians are so unwilling to answer questions that would seem to commit them to a certain strategy. It is also why salespeople ask very specific questions like ’If the price were right, would you buy today?’ They know people feel foolish and dishonest if their words and actions do not match.

Individuals have also been found to be increasingly willing to purchase a product related to a cause that they previously committed to (when buying a product a donation is made to a rainforest protection charity).

The principle is: people tend to feel the need to fulfil written, public and voluntary commitment.

3 Social Proof.

We use others’ behaviour to determine what is correct and accepted. We look for social proof: what others do, say and think. People are persuaded more by the actions of others than by any proof we can offer. This is proposed to be especially true when we are unsure of ourselves. If a decision is ambiguous, we are likely to accept others’ actions as the correct route. We are more likely to imitate behaviours of those who we consider similar to ourselves.

People can therefore be persuaded by others’ actions: they are followers of fashion. If you want to persuade a person in your life to act in a certain way, you can tell them stories of people similar to themselves and the actions that they engage in, in order to back up your own suggestions.

If people are told most people in their area (immediate environment) complete their tax forms on time or own a particular product, they are more likely to ’follow suit’. All parents know the power of peer pressure in their children. This is why hotel chains tell you that previous guests behave in a particular way (i.e. re-use their towels, use room service).

The principle is: people follow the lead of others perceived to be like them.

4 Authority.

Once an individual in a position of authority has given an order, we are said to stop thinking about the situation and to start responding as suggested. People show their authority by uniforms and titles; by particular ways of speaking or acting. In doing so they ’command authority’, which means you are more likely to follow their advice.

People like us can also employ the technique, through hinting to others how much we like a gadget or car belonging to a celebrity, for example; if they have it, it must be good.

The principle is: people tend to defer to ’experts’, ’authorities’ or ’celebrities’ who provide ’shortcuts’ to decision-making (advice) requiring specialized information. In short, we follow those we respect.

5 Scarcity.

Products will be more popular when they are available for ’a limited time only’, or when they are in short supply and likely to sell out — ’only 10 iPhones left in store’. Organizations have closing down sales showing the scarcity of time. Products show ’limited editions’. Anything that is rare is seen to be more valuable. Any resource that is ’running out’ is therefore seen as more desirable.

Further, if you have some information that few other people have, businesses are willing to pay for it. Insights into specific consumer behaviour, for example, can be priced highly. In order to persuade, therefore, the scarcity of an aspect of the product should be highlighted.

The principle is: people value (much more) what is scarce and rare.

6 Liking.

We like people who are like us; and we tend more to follow their advice. Thus the more we share with others (language, education, worldview and religion) the more we are likely to be persuaded by them.

A number of factors lead to ’liking’. Physical attractiveness plays a role, with research showing that we believe good- looking individuals have more desirable traits such as being kind and intelligent. We like those who are similar to us — this seems to be the case whether we are alike in terms of opinions, personality or lifestyle. Co-operating and having to work together to achieve mutual goals also results in liking. We also develop liking for those who compliment us, believing and accepting these compliments, as well as positive feelings towards those who have praised us.

The principle is: people like others who are similar to them, who (also) say they like (compliment) them.


Cialdini, R.B. (2007). ’Influence: The Psychology of Persuasion’. New York: HarperCollins Publishers.

Gass, R., & Seiter, J. (2010). Persuasion, social influence, and compliance gaining (4th ed.). Boston: Allyn & Bacon.