Though the experiment was designed to last for 14 days, it had to be stopped after just six days.
It had to be stopped because of what was happening to the participants.
The interactions between the prisoners and guards had become hostile and degrading.
The guards had become aggressive and brutal, and the prisoners were passive and depressed.
As a result, five of the prisoners had to be released early because of the severe negative emotions.
Even the researchers were affected, and they began to overlook what was happening.
Instead of halting the experiment, they let it continue.
They themselves had become dehumanized by the situation they had designed.
Finally, they realized that the experiment had to be stopped.
What this experiment demonstrates is the powerful effect that situations can have on human behavior.
Given a position of power, people can begin to behave differently than they normally would.
They can begin to behave in an aggressive manner， while those with no power can became passive and depressed.
In other words, the experiment shows that situations can cause abuse of behavior.
（This experiment demonstrates that situations can have a powerful effect on human behavior.）
There are some important criticisms of this experiment.
One criticism is that it is an example of unethical research.
It went on longer than it should have.
It is also unrepresentative since the participants were mostly white, middle-class males.
Despite the criticism, the experiment remains an important study of human behavior.
Recent examples of the Stanford Effect may include the treatment of prisoners of war by American soldiers in the Iraq war.
Other possible examples include bullying at school and gang behavior.
According to the head researcher, Philip Zimbardo, it helps to explain how ordinary people sometimes turn evil.
If situations do influence human behavior, then managing situations can be a way of controlling people.
（There are some important criticisms of this experiment.）
（In a bullying situation, some students take on a new, evil personality.）
（A degrading experience makes people feel worthless.）
（Those without power can become passive and depressed.）
