He is best known for his work with the Stanford Prison experiment. The Stanford Prison Experiment was and experiment were 24 male students were selected to prisoners and guards. They were put into a simulated prison and Zimbardo viewed the experiment. The experiment was scheduled for two weeks but only lasted six days. The guards started to become hostile and the prisoners started to show signs of extreme stress and anxiety. The experiment showed the powerful role that a situation can have on human behavior. He also did research on shyness and heroism. He is also known for the Discovering psychology video series.