place a guy in total sensory deprivation for three years and see what happens. yes, it’s been done.
How about a trip to the dentist:
A group of masked guards in riot gear shackled his legs and hands, blindfolded him with black-out goggles and shut off his hearing with headphones, then marched him down the prison corridor.
and the result:
He had been kept in a blacked-out cell, unable to see or hear anything beyond it. Most importantly, he had had no human contact, except for being bounced off the walls from time to time by his interrogators. As a result, he appears to have lost his mind. I don’t mean this metaphorically. I mean that his mind is no longer there.
and who would perform such an experiment? why, the US government, of course.