If you think about any one of the extremely successful people you know, it's almost guaranteed that one of their skills is the ability to influence and persuade other people.

But being persuasive means being convincing--which means sounding intelligent, since few people spend much time listening to people they think are not intelligent.

So how can you instantly sound more intelligent?

Speak more slowly.

According to research, you sound more intelligent if you speak relatively slowly. (Think of it as the Jeff Goldblum effect.) Speaking at a measured pace makes you seem smarter--as if your words are better thought-out (even if they aren't).

Maybe that's because speaking at a measured pace is also a sign of confidence: You aren't rushing your words because you're secure in the value of your ideas, your opinions, and your thoughts.

Granted, the research on speech speed and its impact on perceived intelligence is mixed. Some studies show that speaking more rapidly makes you seem more intelligent, possibly because speed implies certainty.

So what should you do? There's a better approach than simply speaking quickly or slowly, because how quickly you should speak can depend on the situation you're in.

Here's what one study indicates:

  • If your audience is likely to disagree, speak faster.
  • If your audience is likely to agree, speak slower.

Why? When your audience is inclined to disagree with you, speaking faster gives them less time to form their own counterarguments and gives you a better chance of persuading them.

When your audience is inclined to agree with you, speaking slowly gives them time to evaluate your arguments--and factor in a few of their own thoughts. The combination of your reasoning plus their initial bias means they are more likely to actually help persuade themselves.

So if you're preaching to the choir, speak a little slower. If you're not, speak a little more quickly.

And if your audience is neutral or apathetic, speak quickly, so you'll be less likely to lose their attention.

But no matter what you do, think about your rate of speech--because when you need to seem more intelligent or more convincing, how you speak really does matter.