01/10/2014 01:03 EST | Updated 03/12/2014 05:59 EDT

Olympians' aggressive victory stances may be inherited

A victory dance is one thing, but scientists studying Olympians' triumphant body language are now talking about how the aggressive — even threatening — victory stance may be inherited.

Rather than initially expressing joy or pride after winning, researchers with San Francisco State University say athletes instinctively display "aggressive dominance" over the opponents they just bested.

Witness the seemingly rage-filled face of Sidney Crosby after the NHL star scored Team Canada's gold medal-winning goal at the 2010 Vancouver Olympics.

It's likely an evolutionary trait, said David Matsumoto, an SFSU psychology professor and author of the paper published Friday in the journal Motivation and Emotion.

"We see these behaviours occur, like the chest out, torso pushed out, the head titled back, arms raised above the shoulders, a hand in fist, a punching motion, and the face either grimacing or showing aggression and anger," Matsumoto said from San Francisco.

Such bodily reactions are also common among animals, but they have never been studied in humans, he said.

'Don't screw with me'

"Many animals seem to have a dominant threat display that involves making their body look larger," he said.

"The alpha male goes to fight the other in a group and kills the other; the alpha male then shows that victory by enlarging the body and giving a roar, signalling, 'Don’t screw with me.'"

The SFSU researchers wanted to analyze physical gestures by winners in combative or "antagonistic competitions," so they reviewed footage from 42 judo medal matches from the 2004 and 2008 Olympic Games as well as the 2004 Paralympics. (There are 14 divisions or weight classes in judo, spread over three Olympic or Paralympic Games.)

Video of judo players from more than 35 countries was reviewed.

While dozens of different behaviours were coded "right at the moment of winning or losing a match," a consistent behaviour among the victors was the displaying of an enlarged body with aggressive facial contortions, Matsumoto said.

"It's like saying, 'Who's the boss?'"

The intensity of the physical cues was ranked by psychologists on a scale of 1 to a high of  5.

As for whether the initial chest-thumping celebrations might simply be learned behaviours rather than innate reactions, Matsumoto, who coached the 1996 and 2000 U.S. Olympic judo teams, said examinations of congenitally blind judo players from the 2004 Paralympics would seem to indicate otherwise.

'Power distance' across cultures

"They're also producing the same expressions, even though they've never been able to see from birth," he said. "They didn't learn that from watching others, so it's got to be something ingrained in all of us."

Matsumoto added that the intensity of the aggressive displays from athletic champions appeared to differ across cultures. One theory is that the expressions of triumph might depend on the "power distance" of a person's cultural background or nationality.

Power distance (or PD), Matsumoto explained, is a measurement representing the degree to which a culture encourages or discourages power, status or hierarchy.

"Other researchers have created a way to measure how different cultures are status-oriented versus egalitarian. We took their data for different countries and correlated it with our data," he said.

Nations on the higher end of the PD spectrum may have a greater need for people to exhibit body language showing power and status, he ssaid. Examples of those nations would be Malaysia, Slovakia, Romania, he said, while countries with less of an emphasis on status orientation include Israel, Austria and Finland.

Matsumoto said North Americans fall in the middle of the pack.

He said he would like to try to replicate the results in other contexts and collect more evidence to strengthen his theory that triumph and pride are separate expressions.