Personality is a set of behavior, cognitive, and emotional patterns than makes an individual different from others. Psychologists have proposed many theories to explain the different characteristics of personalities and its development, but the four major theories are the psychoanalytic, humanistic, trait, and social-cognitive theory. 1- Freud’s psychoanalytic theory ‘ Freud stated that unconscious forces influence personality. Humans have three different levels of awareness, the conscious, preconscious, and unconscious. The unconscious level of awareness is the most important and it holds the base biological instincts, wishes, desires and can be the cause of psychological disorders. Based on the three levels of awareness, Freud proposed a tripartite personality model, the id, ego, and superego. The id is primitive, instinctive, and unconscious part of the personality and it is present at birth. The ego is logical, rational, realistic, mostly conscious, and satisfies the id’s needs. When the id’s needs cannot be satisfied, the ego uses defense mechanism such as repression, denial, or displacement to maintain self-esteem and control anxiety. The superego, which is learned from the parents and the expectations from society to find moral perfection. Freud also stated that sex instinct is one of the most important influences of personality and if not properly resolved, it can create mental health problems. Freud’s stages of sexual development are divided into oral (birth to 1 year), anal (1 to 3 years), phallic (3 to 5 or 6 years), latency (5 or 6 to puberty), and genital (puberty on). One of the most well known characteristic of this theory happens during the phallic stage, the Oedipus complex in boys and the Elektra complex for girls, where the sexual attraction towards the opposite sex parent needs to be resolved or it will cause sexual problems in the adulthood. 2- Humanistic theory ‘ Based on his hierarchy of needs, Abraham Maslow claimed motivation is the root of personality. Another humanistic psychologist, Carl Rogers claimed individuals act according to the conditions set by others. 3- The trait theory – Psychologists Gordon Allport, Raymond Cattell, and Hans Eysenck supported this theory. Allport claimed each individual is born with raw skills that are later shaped by the experiences. Cattell was able to identify two types of traits: surface and 23 source traits. Using 16 of the 23 source traits, he was able to create a personality factor questionnaire, which is still used today in career counseling. Eysenck divided the personality in three dimensions: psychoticism (link to reality), extraversion (sociability), and neuroticism (emotional). 4- Social-cognitive theories ‘ Supported by Walter Mischel, Albert Bandura, and Julian Rotter, this theory is based on the hypothesis that individuals can learn behaviors by social interactions.
Personality can be measured through observation, test, interviews, and inventories to name a few methods. This assessment is not only used in clinical settings to determine therapy progress, but also in business to help with the hiring process. The Minnesota Multiphasic Personality Inventory (MMPI) developed in the 1930s by McKinley and Hathaway is the most common personality test used for the screening and diagnosis of psychiatric problems. Another test very popular in the business and education settings is the Myers-Briggs Type Indicator (MBTI) where individuals are scored on four dimensions, creating sixteen different types of personality and can be associated with career choices and job satisfaction.