William Herbert Sheldon (1899–1977) was an American psychologist and numismatist. Sheldon distinguished himself in both fields; in psychology, Sheldon pioneered the use of anthropometry in the development of his categories of somatotypes.
Through the use of many photographs and measurements of nude figures (many Ivy League students), Sheldon assigned people into three categories of body types in the 1940s: endomorphic, mesomorphic, and ectomorphic. He also assigned personality traits to the body types as well. Endomorphics had fat, soft, and round body types, and their personality was described as relaxed, fond of eating, and sociable. Mesomorphics were muscular, rectangular, strong, and personality-wise were filled with energy, courage, and assertive tendencies. Ectomorphics were thin, long, fragile, as well as brainy, artistic, and introverted; they would think about life, rather than consuming it or acting on it.()