Excerpted from Personality: Theories and Applications, by Hogan & Smither
Personality psychology is the study of human nature. Personality psychologists define personality in different ways. However, they all agree that personality exists – as a set of stable structures and recurring processes inside each of us that brings a certain unique coherence to our thoughts and actions, differentiates us from others, and can be used to understand our behaviors.
The word personality is often used to communicate two different meanings: (1) the impression that someone creates on others; and (2) the “true” inner nature of a person. The first meaning refers to personality from the view of the observer, or personality in terms of the “reputation” of an individual. The other refers to personality from the individual’s perspective, or personality in terms of an individual’s “identity” – what they think of themselves. Both views rest on the assumption that people’s actions can be understood and explained in terms of a stable core of personality. Most theories emphasize one meaning more than the other. And both views are important.
Study of personality has two major traditions – descriptive and explanatory. Descriptive tradition develops taxonomies to classify people or describe similarities and differences amongst people. The explanatory tradition tries to understand why people are the way they are, and comes largely from psychiatry.
In business psychology, we are far more interested in the descriptive tradition as it helps us understand and predict workplace behaviors. The descriptive approach has two related approaches to classifying personality – type theory and trait theory.
Type Theory
Type theory can be traced back to ancient Greece. Theophrastus, the founder of botany, described personality types prominent in Athens during the time of Alexander the Great (circa 350 BCE). His types – flatterer, miser, boorish, talkative, pretentious, arrogant, cowardly, mean (and shameless, gross, and stupid!) can also be recognized today. This literary typology continues to be reflected in popular literature like right-brain/left-brain people, Type A/ Type B personality. At best, they are fun, descriptive, heuristics to understand similarities and differences amongst people.
Types based on physiology were first developed by Galen (circa 150 CE.). The famous physician in Roman Era, who influenced field of medicine in Europe and Middle East well into the 17th century, classified people as per four “humors” – black bile, yellow bile, phlegm, and blood. Too much black bile led to depression, yellow bile led to hostility, phlegm led to lethargy and blood to cheerful disposition. Sheldon’s typology based on physique from the 1950s also gained some popularity – ectomorphs, endomorphs and mesomorphs. He also linked it to psychopathology. Ectomorphs who were tall, thin, people were expected to be shy, retiring, and predisposed towards schizophrenia. Athletically built Mesomorphs would be aggressive and likely to show paranoia. Round, jolly, Endomorphs were likely to become manic-depressive. As we now know, none of these physiological typologies or their predictions held up under scientific research.
The Jungian type theory classifies people based on how they think and what they value. Made popular through the Myers-Briggs Type Indicator, this theory and the assessment is still quite prevalent in the corporate world to promote better relations among people who work together.
Trait Theory
An interesting antecedent of trait theory can be traced to Franz Joseph Gall’s (late 18th century) Phrenology where he connected skull bumps to personal characteristics. He developed detailed charts mapping 27 human capacities to skull bumps. Although Gall’s scientific reputation was damaged due to Phrenology, he provided powerful evidence for the link between brain, mind and body.
Francis Galton (19th century) is widely acknowledged as the father of modern psychometrics, the measurement of individual differences. He introduced concepts like regression line, correlation coefficient, regression to the mean. His work led to development of factor analysis and modern human behavior genetics. While Galton studied ability, and not personality, his work laid the path to study personality traits.
Early measurement of personality was largely associated with the study of mental illness. It culminated in the development of the MMPI (Minnesota Multiphasic Personality Inventory), still in use for psychiatric diagnosis and assessing emotional stability.
Researchers began to study dimensions of normal personality in the 1950s. The California Personality Inventory (CPI) was developed by Gough and the 16 Personality Factor Questionnaire (16PF) was developed by Raymond Cattell.
This long tradition culminated in the 1980s with personality researchers concluding that all existing measures of personality are assessing the same five dimensions – a view that is widely (though not universally) accepted. This came to be known as the Big Five or Five Factor Model.
A popular acronym to remember the Five Factor Model is OCEAN – Openness to Experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism (or emotional stability). The Hogan Personality Inventory was developed in the 1980s based on the Five Factor Model.
