Haney, Banks and Zimbardo -

Stanford Prison Experiment

The study looks at the effect of institutions on the behaviour of the people who live and work in them.  In this case, the study attempts to understand why guards and inmates of a prison may adopt certain types of behaviour as a consequence of the situation in which they find themselves.

The study is not really an experiment, there is no real procedure, attempt to control variables or standardised method for collecting data.  However, it does provide some striking evidence about the effect of the situation.