Step-by-step explanation:
Joan was probably experiencing an specific phobia to monkeys.
A specific Phobia according to the Dsm 5, is when a person has an irrational and desproportionate fear towards a particular object or situation. In this case, Joan had a specific phobia toward animals, specifically toward monkeys.
In her case, Joan unknowingly used a therapeutic method called succesive aproximation which is explained as a type of exposure therapy in which the person gets exposed to their anxiety source little by little until they get familiar with it and the fear associated with such object (in this case, monkeys) dissapears.