Guards & prisoners settled into their new roles, guards adopted to theirs quickly & easily.
Over a few days, the relationship between the prisoners & guards changed:
Guards: became increasingly brutal in their treatment of the prisoners, devising new ways to discipline & harass them.
Prisoners: became increasingly passive & compliant to the guards' orders, behaving like they really were prisoners.
Zimbardo: became immersed in his role, began to resent 'bleeding heart academics' coming to observe him.
Study brought to stop after 6 days