The frustration-aggression hypothesis posits that frustration, which occurs when an individual is blocked from achieving a goal, can lead to aggressive behavior. This theory suggests that the level of aggression is directly related to the degree of frustration experienced, implying that if someone feels thwarted in their attempts to reach a desired outcome, they may lash out in anger or aggression. This connection highlights how emotional responses to obstacles can manifest in harmful behaviors towards others or even oneself.