Zimbardo concluded from his stanford prison study that after prisoners and guards had been assigned roles that deemphasized their individuality, they adopted their designated roles more easily than anyone might have imagined as a consequence of?

The correct answer is : deindividualization

Explanation:

It happens when there is a decreased state of self-evaluation and a low sense of responsibility causing disinhibited behavior.  In other words, you're putting yourself in a different state of mind.  That's removing yourself from responsibility and you end up doing things that are outside of the norm, a little bit more on the deviant side of things.