Researchers at UCLA's Center for Behavior, Evolution and Culture asked participants to guess the size and muscularity of four different men based on photos of their hands. The models used in the study had no discernible differences outside the objects they were handling.
Time and again, participants judged the hands brandishing a gun as belonging to a man up to 17 percent taller and stronger than the others.
"There's nothing about the knowledge that gun powder makes lead bullets fly through the air at damage-causing speeds that should make you think that a gun-bearer is bigger or stronger, yet you do," concludes the study's lead author, associate anthropology professor Daniel Fessler.
The results, according to co-author Colin Holbrook, suggest that we rely on an unconscious mental mechanism that assesses size and strength to determine the likely outcome of a conflict. "We've isolated a capacity to assess threats in a simple way," said Holbrook. "Though this capacity is very efficient, it can misguide us."
The study was funded by the U.S. Air Force Office of Scientific Research, and its findings could impact law enforcement, corrections, and military policies.