Ah, the art of persuasion. It’s a subject that has bugged everyone from Aristotle to advertisers to the kids in your high school debating club. But it turns out that the longstanding puzzle of persuasion might not be as much an art as it is a science. Thanks to research in psychology, we might finally be getting some answers.
The psychology of persuasion focuses on any message intended to shape or change the behaviour or beliefs of others. One of the most studied findings in the field suggests that it is often the medium that gets the message across (Marshall McLuhan would be proud!). Details about the person who is delivering a persuasive form of communication are called source variables, which include the communicator’s credibility and how likeable he or she might be. In general, the more we like the source, the more we’re persuaded by the message. For example, in one study, students were asked to sign a petition where only the physical attractiveness of the petitioner varied. The more attractive the source, the more people signed.
Other source variables involve the expertise of the communicator: is he or she credible and trustworthy? As expected in most cases, the greater the communicator’s perceived expertise, the more persuasive the communication. A recent study looked at the effects of expert sources on neural activity to pinpoint what exactly is going on in the brain when we listen to persuasive messages from experts.
The study found that the left side of the brain was most active in areas involving the interpretation and elaboration of the message. This is consistent with other research suggesting that messages delivered to the right ear are more persuasive, since information entering the right ear is processed by the left side of the brain.
The other brain areas that responded to the expert source included the hippocampus, an area involved in memory formation, and the caudate nucleus, which is linked with trustful behaviour, reward processing, and learning.
But research has also shown that in some cases the medium isn’t always the message. According to one model, we can either process a persuasive message through a “central,” analytic and methodical route, or through a “peripheral,” more automatic route. In other words, you either pay careful attention to the message, or you take more notice of the surface characteristics, like source credibility and likeability. Therefore, if you’re trying to persuade someone, your approach will depend on whether your target is processing the message centrally or peripherally.
For example, if your audience isn’t paying much attention to what you’re saying, they’ll be more persuaded by the number and length of arguments, rather than quality. But if they’re in the central route, carefully reasoned arguments will have more impact. What’s more, repetition can strengthen good arguments, but it hurts weaker ones.
Target variables can also affect how persuasive the message really is. If you’re in a bad mood when someone is trying to convince you, you’re more likely to process the message thoroughly. But if you’re feeling more positive, you’ll tend to look at surface characteristics. It has also been found that if you feel personally involved in the issue, you will be more likely to process in the central route, and analyze the arguments carefully and systematically.
Remember that whenever you write a paper for a class, you’re exercising your powers of persuasion. Likewise when you’re trying to convince your parents to let you use the car for the weekend, or when you’re charming a police officer out of a ticket. Persuasion can be a potent tool when you know how to use it, and sometimes we might be its target without even knowing it. You need to look no further than political campaigns, advertisements, and even the news of “scientific breakthroughs” that assail us daily to get the picture.
Now the question is: are you convinced yet?
