Dave is a clinical psychologist with a specialization in clinical depression and suicidal ideation. one day he is walking home from work when he notices a group of 20 people standing and staring up at the sky. curious, he joins the group and sees a person on the roof of a 30-story building—seemingly preparing to jump. suddenly, someone in the crowd starts chanting "jump." soon the other 20 people start chanting as well—dave included. dave's behavior is likely the result of