joan is an animal trainer, but she has been afraid of monkeys since an earlier attack she suffered. however, because of the money, she has agreed to work with monkeys for a movie studio. at first, just going anywhere near cages makes joan tense, sweaty, and apprehensive. lately though, things have changed. working with such cuddly, affectionate human like creatures is causing joan to wonder why she ever felt such extreme distress. what principle of classical conditioning explains why joan is losing her fear of monkeys?