Biological Theories of Crime

VI. Post–World War II Research on Biology and Behavior

A. Body Physique and Crime

After World War II, research into the biological roots of crime persisted. Following in the footsteps of Lombroso in 1876, Kretschmer in 1925, and Hooten in 1939, William H. Sheldon (1898–1977) attempted to document a direct link between biology (specifically, physique) and personality (specifically, crime) through the development of a classification system of personality patterns and corresponding physical builds (Sheldon, 1940).

Running contrary to prevailing sociological emphases on the environmental correlates of crime, Sheldon chose to instead employ beliefs about Darwin’s survival of the fittest, Lombroso’s criminal man, and Galton’s eugenics. Sheldon argued for an “ideal” type, in which perfectly formed physique joined perfectly formed temperament and disposition. Any combination that deviated from this ideal was associated with disorders of both personality and behavior. He claimed a physical basis for all variations in personality and body build.

During the 1940s, Sheldon developed and tested his classification system, known as somatotyping. He created three classifications: (1) ectomorphs, who were thin, delicate, flat, and linear; (2) endomorphs, who were heavy or obese, with a round, soft shape; and (3) mesomorphs, who were rectangular, muscular, and sturdy.

In subsequent studies of juvenile delinquency, Sheldon argued that mesomorphic types were more likely to engage in crime, ectomorphs were more likely to commit suicide, and endomorphs were more likely to be mentally ill. Although Sheldon linked physical and psychological characteristics and concluded that both were the result of heredity, he failed to support that conclusion with valid statistical methods.

Also during the late 1940s and early 1950s, Sheldon Glueck and Eleanor Glueck conducted longitudinal research into juvenile delinquency using control groups and added to Sheldon’s list of somatotypes. They suggested the addition of a fourth type they called balanced. In their research, they found support for Sheldon’s proposition that mesomorphs are more likely to commit crime. Among the juveniles they studied, the mesomorphic somatotype was disproportionately represented among delinquents by a ratio of nearly two to one as compared with nondelinquent controls. In addition, whereas only about 14% of delinquents could be classified as ectomorphs, nearly 40% of the nondelinquent controls could be placed in this category. Instead of concluding that body type led to delinquency, the Gluecks (1956) concluded that participation in delinquency (for which individuals are more likely to get arrested) may be facilitated by having a mesomorphic body type rather than an ectomorphic, endomorphic, or balanced body type.

Biological explanations for behavior lost much of their popularity during the 1960s with the belief that their inherent implication of inferiority often was misused to justify prejudice and discrimination. In addition, the 1950s and 1960s brought significant advances in the natural sciences and in the social and behavioral sciences. Once again, criminologists and other scientists turned to evaluating the internal components and processes of the human body.