Prisoners wore uncomfortable, ill-fitting smocks and stocking caps, as well as a chain around one ankle.
Guards were instructed to call prisoners by their assigned numbers, sewn on their uniforms, instead of by name.
In the footage of the study, Zimbardo can be seen talking to the guards: "You can create in the prisoners feelings of boredom, a sense of fear to some degree, you can create a notion of arbitrariness that their life is totally controlled by us, by the system, you, me, and they'll have no privacy ...
We're going to take away their individuality in various ways.
Steve Mc Queen's racing suit from motorsport movie Le Mans is expected to sell for £370,000 at auction.