Persuasion: The Third-Person Effect

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Why people think they are less influenced than others by adverts and persuasive messages.

One of the most intriguing things about the psychology of persuasion is how many people say that persuasion attempts have little or no effect on them. Other people, oh sure, adverts, work on them. But not you and I, we’re too clever for that.

Attractive woman holding a bottle of beer? Hah! How stupid do they think we are? We know what they’re doing and we wouldn’t fall for such cheap tactics.

Would we?

Persuasive experiments

So pervasive is this feeling that only ‘other’ people are influenced by things like adverts that many studies have explored the idea, with an initial surge in the 1980s and 90s. Psychologists wanted to see how much people thought they were influenced by persuasive messages like adverts and compare it with actual attitude changes, if any.

Typically these studies first got participants to watch an advert, read a newspaper article or other medium containing a persuasive message. Then they were asked how much it had influenced them and how much it might influence other people. Since the experimenters measured actual persuasion and knew from previous research how influential the messages were, they could compare people’s guesses with reality.

What they found, in study after study, was that participants thought others would be influenced by the message, but that they themselves would remain unaffected. When psychologists looked at the results, though, it was clear that participants were just as influenced as other people. This was dubbed the ‘third-person effect’.

Third-person effect

Reviewing the research in this area, Perloff (1993) found that studies on political adverts, defamatory news stories, public service announcements and many more all showed a robust third-person effect. Similar conclusions were reached by Paul et al. (2000), who looked at 32 separate studies.

Perloff also found that when people don’t agree with the message or judge its source as negative, the third-person effect became even stronger. The effect is also stronger when messages aren’t directly relevant to people.

In other words people are likely to be influenced more than they think on subjects that are currently of little or no interest to them. An everyday example would be seeing an advert for a car, when you’re not in the market for a new car. We’d probably guess it has little or no influence on us, but this research suggests we’d be wrong.

Take back control

The third-person effect is unusual because it goes against the general finding that we overestimate other people’s similarity to ourselves.

This is what psychologists call the false consensus effect: we tend to assume that others hold more similar opinions and have more similar attributes and personalities to ourselves than they really do.

The third-person effect, though, goes in the other direction. When it comes to influence, instead of thinking other people are similar to us, we think they’re different. There are two facets of human nature that support this exception:

  • Illusion of invulnerability. People prefer to believe that they are, on average, less vulnerable than others to negative influences, like unwanted persuasion attempts. We all want to protect our sense of control over our lives. One way we do that is to assume that ads only work on other people.
  • Poor self-knowledge. Although it’s an unpalatable idea, we often don’t know what’s really going on in our own minds (see the hidden workings of the mind). Not only does this make scientific psychology a tricky enterprise, it also means that many of our intuitions about the way our own minds work are scrambled and subject to biases like the illusion of invulnerability. The effect of persuasive messages is a good example of this.

People often react to this sort of research by saying it’s disheartening, which it is. It’s not a happy thought that we don’t know how easily we are influenced because we don’t really know what’s going on in our own minds.

However, sticking our heads in the sand and pretending influence attempts don’t work is likely to increase our vulnerability. On the other hand, if we acknowledging our lack of insight into our own thought processes, we can raise our defences against the power of advertising and messages of influence, and take back control for ourselves.

Image credit: Gbaku

About the author


Dr Jeremy Dean is a psychologist and the author of PsyBlog. His latest book is "Making Habits, Breaking Habits: How to Make Changes That Stick". You can follow PsyBlog by email, by RSS feed, on Twitter and Google+.

Published: 3 August 2010

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