case studyarchival researchnaturalistic observationsurveySigmund Freud developed his theory of human personality by conducting in-depth interviews over an extended period of time with a few clients. This type of research approach is known as a(n): ________.Elon.io is an online learning platformWe have an entire course teaching Psychology grammar and vocabulary.Start learning Psychology nowYour questions are stored by us to improve Elon.ioYou've reached your AI usage limitSign up to increase your limit.