Final answer:
Freud explained normal and abnormal functioning through the influences of the unconscious mind and childhood experiences, as detailed in his psychoanalytic theory. He also introduced the stages of psychosexual development, suggesting that unresolved conflicts or fixations can lead to abnormalities in behavior.
Step-by-step explanation:
Sigmund Freud's explanation of normal and abnormal functioning traces back to the influences of the unconscious mind, childhood experiences, and innate drives of sex and aggression. Freud believed the unconscious mind harbors desires and impulses unknown to our conscious self, which he theorized could be revealed through dream analysis, slips of the tongue, and free association. This accumulation of ideas forms the basis of Freud's psychoanalytic theory, which emphasizes the impact that suppressed emotions and experiences, particularly from early childhood, have on adult behavior.
Freud's theory also introduces the concept of psychosexual development, proposing that personality development occurs in stages, with each stage centered around erogenous zones. Problems in any of these stages, due to inadequate resolution of conflicts or due to fixation, could lead to abnormalities in personality and behavior. Therefore, for Freud, abnormal functioning was often the result of unresolved conflicts and fixations stemming from early childhood experiences.
Although many of Freud's ideas have been critiqued and challenged, his contributions endure in the field's recognition of the importance of early childhood and the complex role of the unconscious mind in influencing conscious thoughts and behaviors.