Typology is the search for common elements or aspects of individuals, art productions, social organizations, and the like, whereby they may be grouped into logical arrangements. Human beings, for instance, may be typed according to physical or mental attributes. Art forms may be typed as representational or nonrepresentational, with many subtypes. Social groups may be classified with reference to the dominant characteristics that differentiate one society from another. The usual procedure is to isolate certain elements and then classify the data by noting resemblances and differences. The result is an abstraction, a category, which it is convenient to employ, but which does not completely denote the individual case or datum. Typology reveals the modal type, the form rather than the substance, of whatever is arranged into categories.
In psychology, the term typology applies to the systematic delineation of basic characteristics whereby persons may be classified into groups. One of the best known typologies of antiquity is that of Theophrastus, whose Characters gives brief accounts of such personalities as the glutton, the avaricious man, and other unpleasant types. For satirical portrayals of types of personalities, Jean de La Bruyere's delineations, based on Theophrastus, are unexcelled.
Interest in typologies based upon temperament is as old as Hippocrates. His belief, as developed by Galen, postulated four basic humors in the body and four corresponding temperaments. A relative excess of blood produces the sanguine type; of yellow bile, the choleric; of black bile, the melancholic; and of phlegm, the slow or phlegmatic. Uncritical and hasty extensions of the modern science of endocrinology continue the opinion that internal chemistry is a major determinant of personality type. Hence, there are references to the adrenal type, characterized by excess of energy, bravery, and readiness to anger; to the hyperthyroid type, marked by intensity and nervousness; and to other types connected with endocrine secretions.
Morphological indices have been used since antiquity as a plausible means for typing persons. In a book attributed to one of Aristotle's pupils there appear brief descriptions of traits believed to characterize various of the lower animals and pictures of human countenances fancifully resembling those of lower animals. The human being, then, is said to have all those phychological characteristics attributed to the animal he resembles. Thus, a broad countenance topped by abundant hair denotes the leonine type of personality. A sharp-featured countenance, resembling that of a fox, indicates a wily, deceitful personality. Physiognomy, as this pseudoscience was called, became popular throughout Europe in the 16th century. In 1743, George II decreed that it be outlawed in England.
Typological schemes based upon protrusions and recessions in the skull were developed by Francis J. Gall and popularized by John G. Spurzheim, his student. Known as phrenology, this aberration was popular for more than a century. Frank Parsons, a pioneer in vocational guidance for youth, advocated as late as 1909 that all young persons should consult phrenologists in order to determine their personality type before selecting a career.
Typologies have been derived from observations, and even measurements, of the body build. The old belief that the entire physique reflects personality recurs in Shakespeare's Julius Caesar: Yond Cassius has a lean and hungry look; He thinks too much: such men are dangerous.
In 1921 Ernst Kretschmer, a German psychiatrist, popularized the view that physique and personality have a one-to-one correspondence. He might have referred to Cassius as an asthenic type; hence, schyzothemic, or thoughtful and uncommunicative. When Caesar said, "Let me have men about me that are fat," he referred, in Kretschmer-ian typology, to the pyknic individual, who is jolly, trusting, and extroverted.
The most complete typology based upon morphology is that developed and publicized by William H. Sheldon about 1940. He delineates the endomorph, whose plump build is associated with a life of physical comforts; the mesomorph, who has a muscular physique and a personality attuned to great activity; and the ectomorph, whose physique is lean and concave and whose personality is characterized by a thoughtful, studious nature. Sheldon based his typology upon accurate measurements of various parts of the body and their relationships to one another. His studies of personalities were conducted by tests, interviews and objective judgments.
The impact of Freud upon psychology stimulated the development of typologies related to psychoanalytic concepts and psychiatric symptomatology. Thus, a person who is incapable of making decisions and who must obtain strength from another is said to be the oral dependent type. A secretive, miserly individual is described as an anal retentive type. It is also currently fashionable to describe the excessively cautious, suspicious person as the paranoid type. Many other psychiatric labels are popularly applied in these typologies, often without any scientific warrant and with vague and shifting connotations.