Julian was always something of a "screw-up" in school. his grades were poor and he was suspended several times during high school for pulling pranks that his teachers didn't find funny. his parents were pleasantly surprised, however, when he went off to college. he enjoyed his biology classes so much that he decided to become a doctor and he began getting a's in all of his classes! his friends in college were the "intellectuals" and he spent many late nights at a local coffee house discussing politics and ethical issues related to the practice of medicine. after a successful first year, his parents were amazed to see him slip back into his slovenly habits and jokester ways when he returned home for the summer. julian's behavior best illustrates the ideas of which personality theorist?