The Psychology of Persuasion

By Robert Cialdini


In 1984 Dr Robert Cialdini published this ground-breaking book, which has been in print ever since (and revised four times). What makes it so relevant today is that many of the lessons he gives (having first extracted them from such unlikely places as con-men investigators of the bunco squad, door-to-door encyclopaedia salesmen, and pollsters) are still only known to professionals in the influence game – for example, marketeers – and not the people who should really know, namely, the public at large.

Is it using you, or are you using it? Never have these words been better applied than in the field of influence, or as Cialdini shows, covert influence. Often people are influenced without being aware of the fact. This is less about things such as subliminal advertising, than the result of careful manipulation using six key triggers uncovered in ‘influence situations’. These six, or combinations of them, in the right setting can operate upon you unconsciously. In one experiment, voters were asked to put a large and unsightly billboard up in their garden advertising a political cause. Not surprisingly most people said no. But, in a similar sample, when people had already agreed the week before to putting up a poster in the window, more of them said yes. But most interestingly, almost the same percentage agreed even if they had simply signed a petition a few weeks before – an act that many could not even remember doing. So, we can do things that later cause us to be influenced and yet we have no awareness of the process.

This particular influence trigger is termed by Cialdini commitment and consistency. We act to remove cognitive dissonance – contradiction between beliefs – in our lives. If someone uses this to advance their own agenda, as in the billboard case, we may not notice. The influence avalanche starts with small nudges that refine and expose us as a certain kind of person. For example, if someone considers themselves a good chef, they will be acting consistently if they then buy a top chef’s knife. False questionnaires are just such a consistency trap. You answer the questions, but the answers are worth far less to the company (often the questionnaires are thrown away) than the new perception they have engineered in you – which is one of ‘caring’ about that company – and, of course, favouring their products.

Not surprisingly, people who revel in self-contradiction and personal eccentricity in decision-making are those who are most resistant to this kind of manipulation.

The next trigger is obligation, which, though universal, is especially strong in Eastern cultures. If you give something or do something for a person, they will feel an urge to reciprocate. This can be manipulated when the thing you demand from them, or contrive to get from them, is far more valuable than the thing you initially gave them. In one experiment, people in a waiting room were given a 10-cent can of soda. Later they were asked to buy raffle tickets costing ten times as much; most of them complied. This simple obligation trick is behind every ‘free gift’ companies often give away.

Authority is the next method by which influence can work. Psychologist Stanley Milgram showed this in his famous experiment, where volunteers continued to administer what they believed were electric shocks long after the ‘subject’ had stopped screaming and supposedly passed out simply because a ‘doctor’ in a white coat had told them to carry on. If there was another authority figure also present of the same rank, who advised them to do what their conscience dictated, almost all of them desisted (which implies the need for authority figures who contradict each other in our culture, as in a law court or parliamentary government).

Authority can reside in something quite trivial, such as physical height, and a study showed that in the vast majority of US presidential elections the taller of the two candidates was the winner. In the United Kingdom there is a preference for tall ambassadors: they have more authority.

We tend to copy the people we like, or at least give them greater consideration than people we dislike. And, not surprisingly, we tend to like people who are most like ourselves. Studies have shown that juries are consistently more lenient with good-looking defendants. And in one experiment, when letters were dropped ‘by accident’ with the hope that they would be posted by the finder, it was discovered that envelopes with foreign names and misspelled addresses were less likely to be posted in neighbourhoods where the majority were not foreign.

It has always been a mystery how large groups of people can stand back and allow some terrible event to take place. People tend to blame ‘society’ when it fact it is the human trigger of social proof. We look at others to see how we should behave, and if no one responds to a woman screaming in the park while obviously being attacked, no one comes to her aid. But if only one person does, then she is likely to be rescued by a group.

The final influencer is scarcity. If you can make something seem rare, people will want it. Scarcity is used all the time in advertising, indeed it is ubiquitous, almost an unquestioned principle of selling. Yet only a moment’s consideration of ‘do I need this?’ is required to balance the ‘my last chance to get’ message beamed at us by marketing departments.

These six triggers comprise the heavy guns of influence. Skilfully woven together with the use of clever comparisons and contrasts, they provide the arsenal of the ‘professional influencer’ – people ranging from politicians to advertisers and con-men. Do they have more in common than is generally believed?

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