(CNN) -- Presidential candidate debates rarely, if ever, change an election's outcome, but they tend to be good for voters, a specialist in political campaign communication told CNN Sunday.
"People tend to look for little moments that encapsulate the whole campaign," said Bill Benoit, a professor in the School of Communication Studies at Ohio University in Athens. He cited the 1992 debate between Bill Clinton and George H. W. Bush, in which the latter's glance at his watch was interpreted by some observers as revealing impatience and aloofness.
"The idea that, when President Bush looked at his watch, that that was more important than months of campaigns in multi-media and more important than anything that anyone actually said in the debates, that just doesn't sound realistic to me," he told CNN in a telephone interview.
Benoit also rejected some political pundits' accepted wisdom that Richard Nixon's 6 o'clock shadow was responsible for voters giving him worse marks in the 1960 televised debate against John F. Kennedy than did those who heard the debate only on radio.
"The evidence for that is really bad," Benoit said, noting that neither audience was randomly sampled.
But debates do matter, he said. "One reason that they matter is that they are almost the only message that millions and millions of people see. In some states, they don't run any ads. The one thing that the most people see is the debates. They have that message in common, even though they read different newspapers and watch different television."
There is plenty of evidence that people learn about the candidates' issue positions and form or change their views of candidates' character by watching debates, he said.
"They can reinforce the attitudes of people who already favor a candidate, and that matters because now, in the general campaign, candidates have to raise money." That's because, in 2008, then-Sen. Barack Obama rejected federal financing for his general-election campaign and GOP candidate Mitt Romney has followed suit.
In addition, those viewers who form a stronger opinion about the candidates are more likely to vote, he said.
Still, it's unusual for an election's outcome to be changed by debates, he said.
"Candidates rarely win or lose from ... the debates, but voters always win."