Reality and artifice
No. Amongst other things, people do not volunteer to enter a real prison, they cannot choose to leave when they wish, and they cannot be promoted from Prisoner to Guard.
However, the primary goal of our study was not to simulate a prison. Instead, the environment we created was designed as a context in which to examine evolving relationships between dominant and subordinate groups. For this reason the prison was specifically designed in order to have points in common with many hierarchical institutions: not only prisons, but also places like barracks, offices, and schools.
What was important for us was not that participants saw their environment as a real prison but rather that they experienced the inequalities within that environment as real. All the evidence indicates that they did.
Correspondingly, we do not want to generalize directly from what participants did in our study to how people behave in prisons.
Instead, our aim was to use the study to develop theoretical understanding of why and when members of groups either accept or challenge inequality. It is on the basis of this theory that we then generalize to other contexts.