Final answer:
Cesare Lombroso's research in prisons led him to believe that certain physical features, which he referred to as atavistic stigmata, could identify 'born criminals.'
Step-by-step explanation:
Cesare Lombroso, an Italian criminologist and physician in the late 19th and early 20th centuries, is known for his theory of the 'born criminal' and the physical characteristics he believed could be associated with criminality. During his research in prisons, Lombroso identified several physical features that he thought were markers of criminal behavior, including asymmetry of the face or head, large or protruding jaws, low sloping foreheads, high cheekbones, flattened or upturned noses, large or fleshy lips, and insensitivity to pain. These features, Lombroso theorized, were evolutionary throwbacks -- atavistic stigmata -- that were indicative of a more primitive and savage human development. His work has been largely discredited, as it lacks empirical support and is considered to be grounded in biological determinism and physiognomy, which are now viewed as pseudoscientific.