In Australia the early prison authorities knew this

To control and break the really bad prisoners

They developed a solitary confinement gaol at Port Arthur,

Where prisoners could have no contact with anyone else

they were kept in a dark cell

and even the prison guards wore cloth on their feet when they were on duty so they could not be heard

Even in chapel, they were lead into chapel with bags over their heads and led into their cubical where they could see no one else but the pastor/priest.

This lack of interaction with other people, broke most people and even sent a few people crazy