Republican Presidential candidate Rick Santorum leads the pack when it comes to a particular nonverbal tic: blinking, according to a tabulation by University of Minnesota's Smart Politics blog.

During the GOP debate on Saturday, Jan. 7, Santorum blinked 793 times, at more than twice the average rate of the other five candidates, according to Smart Politics, which counted all of the candidates' blinks during the debate.

The total blink tally for all candidates was 2,284 on-camera blinks made while they were speaking during the ABC debate. The second blinkiest candidate, Mitt Romney, came in at 691. Smart Politics additionally noted that Santorum also frequently looked down and to his right while answering the moderator or responding to statements made by other candidates.

"In short, Santorum's nonverbal communication cues do not make him look comfortable, and, as a result, they do not put the viewer at ease when watching him," reads the post, authored by Eric Ostermeier, a research associate with the university's Center for the Study of Politics and Governance.

People normally blink at a rate of about 20 per minute, an action that moistens the eyesand keeps insects and debris out, according to David Givens, an anthropologist and author of "Crime Signals: How to Spot a Criminal before You Become a Victim" (2008, St. Martin's Press).

An increased rate of blinking is a sign of stress, anxiety or psychological arousal of some kind, and it's connected to the flight or fight response, which is generated by the nervous system in response to a threat, according to Givens. On television — the debates were broadcast by the ABC network — the average blink rate increases to 31 to 50 blinks per minute, he said.

According to the Smart Politics calculation, Santorum exceeded this threshold, clocking 61 blinks per minute while speaking for 12 minutes, 55 seconds, total.

"We pick up these cues without knowing what we are seeing, but we get a feeling for the person from these cues," Givens told LiveScience. "With rapid blinking it shows the person is not comfortable, that there is something exciting him. Whether it is really telling a little truth or not being sure of the facts or being really uncomfortable on the stage, all of these are negative things that we pick up on."

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The blink commands originate in an ancient part of the brain, the midbrain. As more of the neurotransmitter dopamine is released from the midbrain, it signals the facial nerve to blink the eyelids faster, according to Givens.

We share the blinking stress response with our primate relatives, it evolved before our ability to speak; and because blinking is such an old function, it is difficult to control consciously, he said. [8 Humanlike Behaviors of Primates]

While Santorum may have out-blinked his competitors on Saturday, his 61 blinks per minute is hardly record setting. During the 1996 Presidential debates, Republican nominee Bob Dole clocked an average of 147 blinks per minute. His rival, future President Bill Clinton, averaged 99 blinks per minute and maxed out at 117 blinks per minute while talking about teen drug use, a touchy issue at the time, according to Givens.

"It would still give you, the viewer, a feeling there is some stress there, something that is not relaxed," Givens said of Santorum's blink rate.

The candidate who blinked the least on Saturday's debate was Rick Perry, with an average of 15.9 blinks per minute. Next up was Ron Paul, with an average of 17.1. Their blink rates are low, but within the realm of normal, according to Givens. And they indicate — no surprise — a lack of stress, he said.

The other extreme — too little blinking — can also disconcert viewers. In the 2004 Presidential election, Democratic candidate and retired Army general Wesley Clark blinked between two and four times a minute, according to a calculation by Anna Holmes for Salon.com.

"It made people feel really uncomfortable," Givens said.

You can follow LiveScience senior writer Wynne Parry on Twitter @Wynne_Parry. Follow LiveScience for the latest in science news and discoveries on Twitter @livescience and on Facebook.