Brad Bushman, a psychology and communications professor at Ohio State University, takes a broader view. Bushman researches the psychological mechanisms behind gun violence: Does having a weapon around make us more aggressive?
Over the years, Bushman explains, dozens of studies have confirmed what researchers dub the “weapons effect”: People act more aggressively in the presence of a weapon, especially when something angers them. One study by researchers at Harvard found that drivers with guns in the car were more likely to engage in road rage, closely tailing other drivers and making obscene gestures—even when researchers controlled for things like gender, age, urbanization, and more.
Similar studies in labs have found that the presence of a gun causes participants enraged by another person to choose to make that person physically uncomfortable for longer periods of time, from delivering more electric shocks to forcing them to hear louder noises or keep their arms plunged in ice water for longer. In a review of 50 such studies, including more than 5,000 participants, Bushman found not only that the weight of the evidence support the weapons effect, but that the effect was also seen, though not to the same degree, with those who hadn’t been angered.
