The Varieties of Human Physique

The concept of "The Varieties of Human Physique" by W.H. Sheldon is a discredited theory that attempted to link human body shape with personality traits. Sheldon classified physiques into three types, or somatotypes: endomorphic (round, fat), mesomorphic (muscular), and ectomorphic (slim, linear). Each individual was assigned a three-digit number representing their degree of each type.1

Sheldon associated specific personality traits with each somatotype: endomorphs were seen as relaxed and extroverted, mesomorphs as active and competitive, and ectomorphs as introverted and restrained. This theory, known as constitutional psychology, has been largely abandoned due to a lack of conclusive evidence and the problematic notion that body type predicts personality or morality.123