The weapon may not make the man, but it certainly makes him loom larger, according to a new study by a team of UCLA researchers.
Their study, released Wednesday in the journal PLoS ONE, shows that a person holding a gun seems taller and more muscular in the viewer's mind than a person holding a tool or other object.
The paper, funded by the U.S. Air Force Office of Scientific Research, is part of a larger project to understand human decision-making in potentially violent situations.
Countless creatures, humans among them, fight among their own kind for resources such as food and mates, said lead author Daniel Fessler, an evolutionary anthropologist and director of UCLA's Center for Behavior, Evolution and Culture.
"Chickens and lizards and lots of other vertebrates have to face the problem: 'When I encounter another chicken or lizard, do I advance against the opponent, do I retreat or do I try to appease them?' " Fessler said. "All things being equal, the bigger, stronger individual wins the conflict."
The more intelligent a creature, the more involved that threat assessment gets. Chimpanzees, for example, have been shown to attack other chimps when their own side has a 3-1 advantage. Our own species is big on wielding weapons.
But despite our complexity, Fessler and his colleagues theorize that the many factors that go into assessing a threat in our species might be represented in a very simple and primitive way in the brain: simply as an image of the person's size and strength. In other words, our threat assessment operates through a system in the brain that evolved long ago and is likely shared by many other animals.
"Natural selection is often said to be a tinkerer, not an engineer.... Traits that evolve by natural selection do not come from scratch," Fessler said.
To test this theory, researchers set up a series of experiments in which they had hundreds of participants look at photos of hands holding different objects: handguns, handsaws, power drills and caulking guns. (The hands matched one another in size and appearance.)
Participants were asked to look at the photos and estimate the size of the person holding each object and how muscular he was by choosing one of six body types.
In one round of the experiment involving 628 viewers, the researchers found that men whose hands held a .357-caliber handgun were thought to be almost 5 feet, 10 inches — more than 2 inches taller than men whose hands held a caulking gun.
Men with drills were also on the higher end of the height and strength scale — perhaps because of viewers' estimates of the strength it would take to hold a drill — but they were still judged to be about half an inch shorter than the gun toters.
To make sure the viewers were not simply judging based on the weight of the objects, the researchers ran another test using a paintbrush, a kitchen knife and a squirt gun. Even though for some reason the viewers associated the kitchen knife more with women and the paintbrush more with men, the kitchen knife still made the holder seem bigger and stronger than either the paintbrush or the squirt gun did.
On average, Fessler said, viewers thought gun wielders were 17% taller and stronger than those holding the caulking guns.
"I was a little surprised — I was kind of looking for the flaws in the study — but I think they did a pretty good job of convincing me they have a reasonable hypothesis," said Edward Hagen, a biological anthropologist at Washington State University Vancouver who was not involved in the study. "Have they convinced me that it's correct? No, but I think it's a good start."
Hagen suggested an additional way to test whether the threat from a weapon heightens the holder's apparent size and strength: See how large and strong a gun holder seems when the muzzle is pointed directly at viewers, compared with away from them.
He also said that further work in this area could be useful for law enforcement officers and soldiers needing to accurately size up threats in fast-moving situations.
"The more we understand human psychology with regards to human threats and threat assessment … the better we might be at training people in terms of making accurate assessments," Hagen said.