Women are more likely to use direct aggression in private, where other people cannot see them, and are more likely to use indirect aggression (such as passive-aggressive behavior) in public. Men are more likely to be the targets of displays of aggression and provocation than women. Studies by Bettencourt and Miller show that when provocation is controlled for, sex differences in aggression are greatly reduced. They argue that this shows that gender-role norms play a large part in the differences in aggressive behavior between men and women.