A young girl was constantly sucking her thumb as form of hostility and rebellion towards others.
Erickson challenged her by calling her stupid because she was not being clever and wasting her hostility on a lot of people that didn’t count.
In this way, he applied the principle of joining the patient. He then prescribed the symptom by telling her when and to whom she should direct her thumb sucking in order to cause maximum irritation.
By making the thumb sucking obligatory, Erickson reframed it into something she could no longer enjoy because she didn’t want to be obliged to do anything.
Some people refer to this as reverse psychology.