When you want to convince someone that your point of view stronger than someone else’s, you might avoid mentioning any opposing opinions. After all, that would give people an opportunity to consider those views. But research shows that mentioning an opposing argument might be your best strategy.

McGuire’s inoculation theory

Instead of waiting to address the opponent’s argument after it has been delivered to your audience, why not warn people ahead of time? Psychologist William McGuire said you can make people resistant to a persuasive argument by pre-exposing them to a line of attack that they are likely to hear in the future.  To use one of his examples, let’s say you want to convince people that brushing their teeth after every meal is a good idea. You could present your argument and then add, “You’re apt to hear an opposing point of view,” and leave it at that, with no elaboration. Or you could say, “You might hear an opposing view that brushing your teeth too often could damage your teeth,” and then give a compelling argument why that is not true.

Why give both sides

When you briefly mention the opposing view and then debunk it, it acts similar to the immunization process.  Expose someone to a weak form of a virus, and the body builds immunity to the virus, a defense against future attack. If you present an opponent’s position and give a compelling explanation of why that view is inferior to yours, people have time to consider their position and are likely to form their own counterarguments against that point of view, according to McGuire’s experiments.

The key is to inoculate your audience early. Schools take this approach with smoking: They start communicating anti-smoking messages early, when children have strong anti-smoking attitudes and have not been exposed to messages favoring smoking, such as the words (peer pressure) they hear from others in their age group.

When you mention an opposing view and then counterargue, one reason the audience will resist the other position is that you were candid enough to provide both sides.  If you deliver a one-sided argument, you can devote more time to your position, but readers or listeners will think you conveniently omitted the opposing perspective. Consequently, you lose credibility.