Who’s Doing the Persuading

17.05.2016 |

Episode #3 of the course The psychology of persuasion by Jake Teeny


Although you may want to believe that only the content of a message persuades you, oftentimes less central features, such as who’s delivering the message (i.e., the source), can be equally influential.

Imagine for a moment you were told that eating almond butter is healthier for you than eating peanut butter. Now, if a high school student informs you of this, it will probably be less convincing than if a nutritionist gives you the same advice.

Thus, in this regard, the source of the message (the high school student vs. the nutritionist) is a relevant feature in the persuasiveness of the appeal.

Now, though, let’s consider what happens if your nutritionist recommends that you purchase a certain type of cell phone. If you’re not scrutinizing the message, you may automatically think that your nutritionist is a “credible” source, so therefore, the recommended phone must be good!

But what does a nutritionist really know about cell phone technology?

Marketers rely on the fact that we usually don’t pay close attention to advertisements, in which case using celebrities or attractive models—who should have no effect on how persuasive the message is—actually serve to automatically persuade us.

And unless you’re paying close attention to the appeal, there are three characteristics of the source that influence you: expertise (how knowledgeable the source is about the topic), trustworthiness (how honest s/he is with the message), and attractiveness (how appealing or how much you like the person).

If you consider television commercials, you can probably recall a lot in which a “doctor” recommends the product. Why? Well, doctors are regarded to have high expertise—and we’ve been trained since our youth to automatically find the advice of experts more persuasive.

Now consider a political ad: Don’t they often have “real testimonials” from voters on behalf of the political candidate? These commercials are tapping into the trustworthiness aspect. That is, we’ve been raised to find “honest appeals” more persuasive.

And across pretty much every commercial you see, the source of the message will likely be attractive. In general, we like attractive people, so naturally, we will come to like what attractive people like—namely, the product or politician they’re advocating.

Now even though these source characteristics are often meant to automatically persuade us when we’re not paying attention, carefully scrutinizing the message can ensure we’re only influenced by the true merits of the appeal.

However, even if you are able to separate the specious persuasive effects of the source from what should actually persuade you, that doesn’t mean there aren’t other aspects of a persuasive message that are equally devious.

To learn more about the powerful effect of sources on your beliefs, learn about the famous California water study.


Recommended book:

“Influence: Science and Practice” by Robert B. Cialdini


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