Few methods beat email for sending communication blasts, getting a note in front of a far-flung sales prospect or employer, or attaching pictures and documents.

Too bad about the downside: You may not sound your smartest.

New research shows that text-based communications may make individuals sound less intelligent and employable than when the same information is communicated orally. The findings imply that old-fashioned phone conversations or in-person visits may be more effective when trying to impress a prospective employer or, perhaps, close a deal.

Vocal cues “show that we are alive inside — thoughtful, active,” said Nicholas Epley, a professor of behavioral science at the University of Chicago Booth School of Business and one of two co-authors of the paper, “The Sound of Intellect,” published in Psychological Science this month. “Text strips that out,” he added.

In the first of a series of experiments presented in the paper, the researchers recruited 18 M.B.A. candidates from Booth. The students were asked to prepare a brief pitch to a prospective employer — a roughly two-minute proposal that the researchers recorded on video.

Separately, the researchers recruited 162 people who were visiting the Museum of Science and Industry in Chicago to evaluate these pitches. Some of these museumgoers watched the video, a second group listened to the audio without watching the video, and a third group read a transcript of the pitch.

What the researchers found was that the evaluators who heard the pitches — whether in the audio or video version — “rated the candidates’ intellect more highly” than those who read the transcript, the paper reported. Those who listened or watched also rated the candidates more likable and, critically, more employable.

If you are thinking, “Well, that’s a silly experiment. The written version was meant to be heard, not read,” the researchers have a response. In a second experiment, the researchers asked evaluators to read a written pitch that was specifically drafted by candidates to be read (rather than spoken aloud). Same result. And in a third experiment, they verified the findings with a group of evaluators who were professional recruiters from Fortune 500 companies.

The researchers also turned the experiment on its head by asking museumgoers to read written pitches aloud. As before, the evaluators judged the candidates as more employable in the oral pitches, even though they had been specifically prepared to be read. “If you read aloud my written pitch, you’d sound smarter than my written pitch,” Dr. Epley said.

Dr. Epley did not control for writing ability, but given that these were students at a top business school, Dr. Epley assumed they were better-than-average writers, suggesting that the results did not reflect poor writing skills.

Nor did he select his subjects for excellence in public speaking. Rather, he says, the results validate and expand upon previous research showing that the cadence and intonation of voice allows listeners to do a better job of gauging a person’s thoughts than the same information communicated in writing.

“How do we know that another person has a mind at all?” Dr. Epley said. “The closest you ever get to the mind of another person is through their mouth.”

“People abuse text-based mediums like email. That’s a disaster in a lot of ways,” he said. “Email is really good for sending a spreadsheet, but it strips out some of your humanity.”