Personality Types

A personality type is a psychological classification of different kinds of people. Types are different from traits: a type sorts people into distinct categories, while traits are characteristics that people possess in differing degrees. For example, according to type theories there are two kinds of people — introverts and extroverts; according to trait theories, introversion and extroversion are the two ends of a continuous dimension, with most people somewhere in the middle.

Many broad perspectives have grown up around personality: the dispositional (trait), psychodynamic, humanistic, biological, behaviourist, evolutionary and social-learning perspectives. Because no single theory covers every aspect of personality, most researchers take a mixed approach. Broadly, two main approaches are used to explain personality:

1. The Type approach classifies personality by grouping people according to a set of shared behavioural characteristics. Examples include:

• the Myers–Briggs Type Indicator;
• Friedman and Rosenman's Type A behaviour pattern;
• Kretschmer's body-type classification;
• William Sheldon's somatotype classification; and
• the fluid (humoral) type classification traced back to Hippocrates.

2. The Trait approach focuses on specific psychological attributes, based on the idea that individuals differ in unique and stable characteristics. A trait is a characteristic that is fairly unchanging and predictable — shyness, for instance, is usually stable in a person. Some traits are innate (present in a basic form from birth), while others are acquired through learning, such as tidiness or untidiness. Psychologists like Eysenck, Cattell and Allport treated certain inherited traits as “cardinal” and proposed a biological basis for personality, arguing that people inherit a type of nervous system that shapes how they learn and adapt. Sigmund Freud and Neo-Freudians such as Jung — who described personality in three parts, the id, ego and super-ego — put forward the psychodynamic theory, which assumes a constant interaction between nature (innate instincts) and nurture (parental and environmental influences). …