Body Type in Popular Psychology

One of the wider detours off the scientific path that personality theory has taken is that the characteristics of a person’s body determine personality. Sometimes known as physiognomy, the idea that facial features and body shape are accompanied by certain personality traits dates back at least to the ancient Greeks, with nineteenth-century echoes in the criminal anthropology of Cesare Lombroso (1835–1909). According to Lombroso, the criminal type is less evolved and can be detected by his atavistic simian (apelike) features, which Lombroso called stigmata. We have Lombroso to thank for every literary villain with a heavy brow, low forehead, long arms, large ears, thick hair, or shifty, deep-set eyes.

A German psychiatrist named Ernst Kretschmer (1888–1964) gave such ideas a scientific patina in a 1921 book called Physique and Character. In the book, he claimed that people with short limbs, round faces, and thickset bodies tended to have mood fluctuations and to be manic or depressed, thin people with long limbs and narrow faces were introverted, shy, cold, and antisocial, and people with more balanced physiques (at neither extreme) were energetic, aggressive, and cheerful. The problems with this theory were quickly pointed out by other scientists: many people violate the rules. Short, overweight people who are shy are fairly easy to find, as are tall, thin manic-depressives. The idea did not die, however, and it soon had a new champion in Harvard physician/psychologist William Sheldon (1899–1977).

Inspired by Kretschmer’s book, Sheldon spent several decades collecting information on body types, which he called somatotypes, and personality. In the course of his research, Sheldon photographed at least 4,000 male college students and recorded their physical measurements. Based on his data, he decided, exactly like Kretschmer before him, that there were three basic body types: the endomorph (soft, rounded, plump), the mesomorph (hard, square, big-boned, muscular), and the ectomorph (tall and thin with a large head). He named them for the three layers of cells, which are the first to differentiate in the human embryo, each of which forms a different body system eventually. In addition to taking all those measurements, Sheldon also gave personality tests to some of his subjects, and he interviewed and observed many more. Based on this, he concluded that each somatotype is associated with a particular personality pattern.

According to Sheldon, the endomorph is social, talkative, relaxed, and hedonistic; whereas the mesomorph is energetic, assertive, courageous, optimistic, and devoted to sports. The ectomorph is introverted, shy, and intellectual. Sheldon’s theory aroused a great deal of public and professional interest when first published in the 1940s, but both his ideas and methodology quickly came under attack by psychologists who noted that his theory completely ignored such environmental factors as socioeconomic status, health, and nutrition, all of which might have a fairly large effect on body type. Another problem had to do with the correlations between the three body types and the three personality types. The numerical relationships he found were much stronger than are usually found in psychological research, which may have been due to the fact that Sheldon, expecting certain results, conducted all the data collection on both sets of variables himself. Although Sheldon’s theory was popular into the 1950s, it has since faded into near-complete obscurity, yet the words he created— mesomorph, ectomorph, and endomorph—are still in use occasionally to describe different body types.


  1. Sheldon, W. H., and Stevens, S. S. The Varieties of Temperament: A Psychology of Constitutional Differences. New York: Harper and Brothers, 1942.