You’ve been reading the past few weeks about a study of TED talks conducted by Science of People. Their researchers looked at the difference between the talks that generate tons of interest online and the ones that get fewer views and less acclaim.

They had evaluators watch these top-level speakers and rate each one for Charisma, Credibility and Intelligence. The results would be useful for anyone who’s getting on that TED stage. But they’re also helpful for any of us who speak as part of our marketing mix. What’s good for a TED talker is going to be good for you next time you’re in front of a professional association or a networking group.

Most of the study results were intuitive:

• Speakers are more charismatic when they have more vocal variety.
• Speakers who use their hands are more credible.
• Nonverbal communication makes all the difference when we evaluate a speaker

But this one surprised me.

Speakers who smile more often are considered more intelligent than those who keep a more serious expression.

Interesting. Because there’s considerable research showing that more powerful people in business smile less than their lower-ranking colleagues. Smiling is often associated with a need-to-please that doesn’t jibe with confidence and command.

Many studies point to a gender difference in smiling – girls smile more than boys even as babies, and that differential continues into adulthood. But it levels out when women move into higher corporate positions where people-pleasing is not part of the job description.

And we tend to think of smart people, men or women, as being serious about their subject.

And yet … Science of People found a strong correlation between smiling and the perception of intelligence. In fact, smiling was the most important factor for intelligence ratings.

How much do you have to smile to be considered smarter than the average bear? They say 14 seconds of smiling was the tipping point for higher ratings in intelligence.

The smile matters even, maybe especially, when the subject is a serious one. The message for speakers is no laughing matter: if you want your audience to think you’re smart, show those pearly whites.

One more note from my own research (which involves watching myself on video and cringing). The older I get, the more important it is for me to intentionally smile when I’m in front of a room. The dreaded Resting Bitchy Face can make me look cranky when I’m in a perfectly good mood. And nobody wants to listen to a crabby speaker.

If you find people asking you, “What’s wrong?” more often these days. If they wonder why you’re mad at them when you’re not angry at all. If you regularly get that concerned look as they urge you to smile. You might be in the same boat.

And I’m all for having the face you have most of the time, smiling or not. It irks me when people (usually men) walk around giving people (mostly women) an order to smile.

It’s worth checking out though, when there’s an audience in front of you and it matters how they perceive you. You might need to crank up the wattage on your smile. To keep them happy … and to let them know how brilliant you are.