Brandishing a gun or wielding a knife really can make you look like Rambo, scientists have discovered.
In tests, US researchers proved that perceptions of size and strength are influenced by the sight of a threatening weapon.
Shown photographs of identical men's hands holding different objects, volunteers judged individuals with guns to be physically bigger and stronger. A similar result was seen with knives. Men grasping a large kitchen knife were assumed to be larger and more muscular than those holding non-threatening objects.
"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," said study leader Dr Daniel Fessler, an anthropologist at the University of California at Los Angeles (UCLA).
The study is part of a project funded by the US Air Force Office of Scientific Research looking at how people make decisions in potentially violent situations.
In one test, researchers asked 628 volunteers to look at four photos of men's hands holding either a caulking gun - used to apply sealant - an electric drill, a large saw or a hand gun. All the hands were similar in size and appearance. Participants were asked to estimate the height of each hand model. They also had to judge which of six images of progressively more muscular men came closest to the model's likely size and strength.
On average, volunteers judged the gun-toting model to be 17% taller and stronger than the holder of the caulking gun. Models holding the saw and drill followed the gun-wielder in perceived size and strength.
A second test involved a different group of 541 volunteers looking at photos of male hands holding a large kitchen knife, a paint brush or a child's water pistol. Again, those holding the most lethal object - the knife - were judged to be the biggest and strongest. They were followed by men holding the paint brush and water pistol.
"It's not Dirty Harry's or Rambo's handgun, it's just a kitchen knife, but it's still deadly," said co-author Dr Colin Holbrook, also from UCLA. "And our study subjects responded accordingly, estimating its holder to be bigger and stronger than the rest."
The findings are published in the online journal Public Library of Science ONE.