Hooton conducted an ambitious 12-year study that compared 13,873 male prisoners in 10 states with a haphazard sample of 3,023 men drawn from the general population, searching once more for physical differences. Hooton published his findings in The American Criminal and Crime and the Man, both books appearing in 1939. The books attributed criminal behavior to biological inferiority and "degeneration," ascribing a variety of unattractive physical characteristics to criminals (including sloping foreheads, compressed facial features, drooping eyelids, small, protruding ears, projecting cheekbones, narrow jaws, pointy chins, and rounded shoulders).
By the 1930s, however, biological research was rapidly losing favor, as criminologists increasingly argued that social factors alone cause criminal behavior. Hooton's research was ridiculed in particular, one sociologist dismissing his findings as comically inept in historic proportions (or "the funniest academic performance... since the invention of movable type" [Reuter 1939]). Hooton was condemned for his circular reasoning: offenders were assumed to be biologically inferior, so whatever features differentiated criminals from noncriminals were interpreted as indications of biological