Pollster Matt Towery was having lunch with the campaign manager for a U.S. senator the other day when talk turned to the most recent Republican presidential debate, and Towery's observation about an onstage habit of Texas Gov. Rick Perry.
"I told the guy, 'Do you realize that Perry is trying to look like Ronald Reagan?' "
Towery, who is based in Atlanta, was at one time the debate coach for his former boss, Newt Gingrich. Sensitive to non-verbal nuances, Towery immediately picked up on Perry's gesture, and its echoes of his party's icon.
"Every time someone says something, he cocks his head with a little smile on his face," Towery said. "Reagan would always move his head to one side and act as if he couldn't quite believe what the other person was saying. I guarantee that's what he's trying to do."
Whether voters will look at Perry and think Reagan is impossible to know. But the suggestion speaks to a fundamental debate truth -- how candidates look and act onstage is often just as important as what they say.
As eight GOP candidates gather tonight in Orlando for a third debate in three weeks, viewers will be primed for skirmishes over Social Security, health care and who has the better jobs record.
They also will receive a stream of information about the candidates that has nothing to do with the topics at hand.
Mitt Romney, seeking the presidency for the second time, has mastered the art of appearing deeply engaged in what his opponents are saying, even if they are criticizing him. When he speaks, he alternates aggressive, succinct attacks with deferential remarks.
All of it leaves the impression of a candidate tough enough to rumble but not angry enough to alienate.
"I think he's an improved candidate," said Stanley Renshon, a prolific author on psychology, presidents and politics. "This sounds like a knock, but I mean this in an objective sense. He's gotten better at delivering the sales pitch."
By contrast, Perry sometimes appeared bored or miffed during last week's debate, in part because he seemed to ignore one of the cardinal rules of debating -- the camera is always on, even when you think it isn't.
That take-away, along with sometimes halting answers under a barrage of criticism, raised new questions among some Republicans about his prospects.
Candidates can practice rhetorical flourishes all they want, but when they are standing onstage, they can't hide from the most basic aspects of their physical selves:
Ron Paul is rumpled; Newt Gingrich is overweight; Jon Huntsman's cocked eyebrow telegraphs a certain anxious disdain; Romney is tall and has a great head of slicked-back hair; Perry's snug suits give the impression of a man who, without notice, might run into a phone booth and rip off his tie.
As the only woman in the race, Michele Bachmann faces the double standard that plagues female candidates. Her deep-set eyes are noticeably enhanced by false eyelashes, and she has good and bad hair days.
In an August debate in Iowa, she frequently left the stage to freshen her makeup, and was even late returning once.
In a debate this month in California, Bachmann's hair was more teased than usual.
"They didn't do her hair right," Towery said, "and she looked kind of crazy, like she was coming at you in this attack mode."
An unfair standard, he admitted, but precisely the kind of harsh and subjective judgments people make.
This was a lesson learned brutally by President George H.W. Bush in 1992 in a town hall-style debate with Democrat Bill Clinton and independent Ross Perot.
When the Republican president looked at his watch as he stood to answer a question on whether the poor economy had personally affected him, those watching saw a president disconnected from their problems. Bush later confirmed in interviews that he couldn't wait to get out of there.
The lesson was forgotten by 2000, when then-Vice President Al Gore could not contain his emotions during a presidential debate with Bush's son, then-Texas Gov. George W. Bush.
"I think everybody remembers and is appropriately spooked by Al Gore's bad behavior, his sighing and heaving," Renshon said. "You have to show you are respectful to your fellow candidates, even if you'd like to gut them onstage."
These days, some researchers are studying clues so unnoticeable that they are the equivalent of a dog whistle to voters' ears.
At Kent State University, William Kalkhoff and Stan Gregory are studying the role of "paralanguage" -- non-verbal aspects of speech such as tempo, intensity and pitch that indicate dominance in a debate.
They analyzed a 2008 encounter between Barack Obama and John McCain, stripping out all sounds except a very low frequency that they isolated with a special filter.
By analyzing that frequency, the researchers measured which candidate wielded more "nonverbal vocal dominance" -- or felt more confident -- at different points in the debate. (McCain started off stronger, but Obama finished stronger).
By now, it's a faded memory, but the first televised presidential debate in 1960, between John Kennedy and Richard Nixon, signaled the dawn of a new age of judgment on the part of debate watchers, one that launched a thousand image-consultant careers.
Nixon, sweating under the hot TV lights, his five o'clock shadow visible, seemed nervous and shifty compared to Kennedy, who bore an easy smile and suave demeanor.
People remember that Kennedy won the debate, which was true for TV viewers. Radio listeners, immune to Kennedy's visual appeal, gave the win to the sweaty guy.