Final answer:
Jarrad loses his desire to smoke through aversive conditioning, where the painful electric shock associated with smoking acts as a negative stimulus, eventually leading to a conditioned response that reduces the behavior.
Step-by-step explanation:
Jarrad loses his desire to smoke thanks to a concept called aversive conditioning, a type of behavioral therapy that uses negative stimuli to reduce or eliminate a particular behavior. In Jarrad's case, the negative stimulus is the painful electric shock he experiences whenever he opens his cigarette case or uses his lighter, which creates a negative association with the act of smoking. Over time, this repeated pairing of the shock with the behavior conditions him to avoid it, thus reducing his desire to smoke.