Stanford Prison Experiment

This clip explains Philip Zimbardos Stanford Prison Experiment. Students volunteered to participate as either prisoners or prison guards.

The prisoner participants were arrested from their homes and were kept in small cells for 24-hour periods. The guards worked 8-hour shifts. Although students entered the experiment in good physical and mental health, prisoners became ill and zombie-like while guards became demanding and demeaning. Why didnt any of the volunteers bow out of the experiment?