Sheldon's constitutional psychology

n. The psychology of William H. Sheldon, who suggested that there were three basic breeds of humans called somatotypes in which body form and character are interrelated. The three somatotypes are endomorph, mesomorph, and ectomorph. Sheldon suggested these come about because of the dominance of the inner, middle, or outer portion of the embryonic tube as the individual matures. The inside of the embryonic tube matures into the inner organs of the body, and a person dominated by this physique tends to be soft, spherical, and dominated by the digestive process. The character of endomorphs tends to be warm, sociable, relaxed, tolerant, and affectionate, and they tend to grow fat because of their appreciation of food. Mesomorphs are dominated by the growth of the middle portion of the embryonic tube, which matures into muscle and bone. They tend to have wide shoulders, narrow waists, and a larger proportion of muscle in their bodies than the other somatotypes. The character of mesomorphs is active, aggressive, risk taking, callous, and dominant. Ectomorphs are dominated by the development of the outside of the embryonic tube, which develops into the skin and nervous system. They tend to be tall and skinny with a low muscle mass. The character of ectomorphs tends to be oversensitive, inhibited, tense, and avoidant, with a wish for concealment. Most humans are crossbreeds of the somatoypes as most dogs are crossbreeds, and so most people show a mixture of the body and personality traits associated with the different somatotypes, depending on their particular mix of somatotypes.