Some researchers say that violent people often seek out violent video games, and that the time they spend playing the games is taking them off the streets, leading to decreased crime. The study “real and significant" effect of hot weather on homicides and aggravated assaults, showing that heat is a risk factor for violence. Smoking is a known risk factor for lung cancer, but there is no good evidence that video game playing is a risk factor for violence. Studies have shown that violent video games can have a positive effect on kindness, civic engagement, and well social behavior. Research shows that playing violent video games can induce a feeling of guilt that leads to increased social behavior or positive actions that benefit others in the real world.