Aperson who has an intense phobia of heights is forced to spend an afternoon on the observation deck of a skyscraper. this is a therapy method called

Exposure therapy  

Exposure therapy refers to technique where a patient is gradually exposed and made to face their fears, anxieties and phobias without  the intention of causing any harm or danger. The goal of exposure therapy is to provide a safe environment in which patients can gradually face their fear and learn techniques to overcome it. 

i honestly speaking this is too long