Don't believe a dude with a wide face, says Science. "Here's how the researchers figure the link between facial width and trustworthiness might work: During male adolescence, a surge in testosterone prompts bone growth not only in the spine and limbs, but also in the face. Therefore, a wide face may be a sign of an overall bigger man, one who can get away with being more aggressive and less cooperative. Slighter men might act in a more civilized, and trustworthy, way – out of necessity."