4. The Bystander Effect
The Bystander Effect reveals a surprising side of human nature: in emergencies, people are less likely to help when others are present. This phenomenon came to light after the tragic case of Kitty Genovese in 1964, where multiple witnesses failed to intervene. Psychologists attribute this to diffusion of responsibility—each bystander assumes someone else will act. Classic experiments, like those by Latane and Darley, demonstrated that the presence of a group can drastically reduce the chances of any one person offering assistance.