The idea that people can be born bad goes back at least as far as the Old Testament, which accounts for the transmission of original sin by relating the story of the fall of Adam and Eve.  The Bible’s theological concept of original sin was translated into scientific terms during the first days of the American republic, when Dr. Benjamin Rush, a signer of the Declaration of Independence, proposed a biological explanation for the behavior of people who seemed unable to obey the law.1

The concept of inherent criminality has evolved through many stages since Benjamin Rush’s day. This exhibit asks how proponents of the various biological explanations of criminality presented their theories and persuaded audiences of those theories’ validity.

Phrenology: ca. 1800-1870

The first systematic efforts to identify biological causes of crime were made as part of the broader science of phrenology, an approach to understanding human behavior that is usually traced back to the work of Franz Joseph Gall (d. 1828), an Austrian physician.  According to Gall and other phrenologists, each of our mental abilities is located in a separate part of the brain and functions independently, in relative isolation from the others.  One of the brain’s “faculties” or “organs” can be normal, while another lies dormant or atrophies.

Phrenologists differed over the number and names of the faculties but agreed that crime results when faculties such as acquisitiveness and combativeness become disordered.  Because they were unable to study the brain directly, phrenologists drew conclusions about it from the contours of the skull. That is, they assumed that the development of the brain’s various faculties or organs is reflected in the skull’s bumps and hollows. (Thus critics derided phrenology as “bumpology.”)

Phrenology contributed powerfully to nineteenth-century thinking about criminality as a mental illness.  Championed most strongly by physicians, phrenology encouraged articulation of the so‑called medical model of criminality, which interprets criminal behavior as a sickness and hence properly part of medicine’s jurisdiction.  Phrenology supported the belief that criminals, because sick, are not responsible for their behavior, a belief that became the basis for the legal defense of insanity.  Additionally, phrenology provided a biological (and sometimes hereditarian) explanation for crime. The immensely popular phrenologist Johann Gaspar Spurzheim, for example, argued that criminality can be inherited—-and that through reproductive controls it can be prevented in the next generation.

Benjamin Rush, the American patriot and physician, foreshadowed phrenology in a 1786 speech on “The Influence of Physical Causes upon the Moral Faculty.”  In this and later writings, Rush attributed “innate moral depravity”— by which he meant uncontrollable criminality—to “defective organization in those parts of the body, which are occupied by the moral faculties of the mind.” 2  Moral depravity, Rush argued, is similar to a physical disease, and those who suffer from it are “very properly...subjects of medicine.” 3  But Rush did not argue that moral depravity is usually inherited.  Rather, he believed that most criminalistic people induce their own depravity through gluttony, habitual drunkenness, and other behaviors that damage the moral faculties.

Phrenology peaked about 1850, but it continued to attract adherents throughout the nineteenth-century. Moreover, the phrenological view that people can induce criminal behavior through excessive eating, drinking, and sexual activity led directly to degeneration theory, the next stage in the development of biological theories of crime. 


Degeneration Theory: ca. 1870-1910

The late nineteenth-century physicians and social scientists who studied human degeneration taught that individuals can devolve over the course of a life span.  Self-abuse and excess lead to degeneration, a weakened physical condition that in turn weakens one’s moral capacity and thus leads to crime and other social problems.  However, by obeying the laws of good health and morality, even degenerates can reverse their downward slide and begin to regenerate physically and ethically.

Working before the discovery of genes, degenerationists attributed heredity to “the germ plasm,” a substance that they thought transmitted certain traits through the generations.  Weakened germ plasm, in the degenerationists’ view, is the fundamental cause of most social problems.  According to this way of thinking, a criminal grandfather and sexually promiscuous grandmother—both obviously carriers of unhealthy germ plasm—might produce an insane son and alcoholic daughter, whose offspring, in turn, might bear children who are “feebleminded” (mentally retarded), thievish, or “pauperized” (dependent on welfare).  In the degenerationists’ view, the manifestations of degenerate germ plasm are interchangeable.

To study degeneration scientifically, researchers conducted genealogical research on “bad” families.  This method originated with “The Jukes” (1877), Richard Dugdale’s famous study of a rural clan that, over seven generations, produced 1,200 bastards, beggars, murderers, prostitutes, thieves, and syphilitics.4

The findings of bad-family research alarmed policymakers, who concluded that degeneration could wreak havoc in generations to come.  The message was not entirely gloomy, however, because degenerationists did not view inheritance as fixed and immutable.  If degenerates could be persuaded (or forced) to lead more upright lives, they might produce better “stock” and thus produce fewer social problems in the next generation.


Criminal Anthropology: ca. 1880-1910

Much more pessimistic was the message of the next (and overlapping) group of biological theorists, criminal anthropologists, who taught that some criminals are unchangeable “born” criminals, doomed to lives of crime.  According to criminal anthropologists, born criminals form a distinct criminal type with twisted bodies, minds, and morals.  Low-browed, long-armed, and apelike in appearance, they are in fact throwbacks to an earlier phase of evolution, primitives who are incapable of conforming to the laws of civilized societies.

Combining degenerationist themes with the new science of evolution, criminal anthropology began attracting public attention in the 1880s in both Europe and the United States.  In Europe its main proponent was the Italian physician Cesare Lombroso, whose treatise Criminal Man went through five editions, was widely translated, and inspired many imitations.  With his son-in-law William Ferrero, Lombroso also wrote The Female Offender, the first book on women law-breakers.

Heightening the impact of criminal anthropology was a new method of identifying repeat offenders introduced by a Frenchman, August Bertillon.  Bertillon’s method involved taking a series of measurements of criminals’ feet, forearms, heads, and so on, and then filing this information in such a way that it could be used to identify a criminal if he or she were rearrested—even if the offender used an alias.  The procedure was not based on criminal anthropology (or, for that matter, on any other theory of crime).  Bertillon’s interest, in this period before fingerprinting, lay solely in detecting repeat offenders.  However, his method, which was adopted in both the United States and Europe, so closely resembled the measurement procedures of criminal anthropologists that it helped persuade the public of the validity of criminal anthropology.

Degeneration theory and criminal anthropology converged to convince policymakers and members of the general public of the need for eugenic policies that would prevent socially undesirable people from reproducing.  Eugenic concepts had been advocated for centuries, but they did not become the basis for an organized social movement until after 1883, when the Englishman Sir Francis Galton coined the term “eugenics” to refer to “the science of improving stock” through selective matings.5

Although Lombroso did not draw eugenic conclusions from criminal anthropology, many of his American followers did.  By the end of the nineteenth-century, policymakers were calling for sterilization or lifetime institutionalization of “born” criminals to prevent their reproduction.  But by this time it was clear that many criminals did not exhibit the physical abnormalities predicted by criminal anthropology.  The problem became one of finding a simple and sure method of distinguishing “born” criminals from offenders who merely fell into crime through circumstance.


Feeblemindedness Theory: ca. 1905-1920 and beyond

An apparent solution to the problem of identifying “born” criminals arrived about 1910, with the introduction of Binet’s method of intelligence testing.  Even before this, however, American eugenicists had begun advancing a new biological theory according to which the worst or born criminals are feebleminded (mentally retarded) and “the feebleminded” (persons with mental retardation) are by nature criminalistic.

Feeblemindedness theory was prompted by developments in genetics.  In 1900, scientists rediscovered the laws of inheritance that Gregor Mendel, an Austrian monk, had formulated through experimentation with garden peas.  And early in the twentieth-century, scientists also began to reject the idea that acquired characteristics can be inherited, replacing it with the new view that chromosomal germ cells (what today we call genes) determine heredity.  Applying Mendel’s rules to human inheritance, and assuming that feeblemindedness was a single, inherited trait, eugenicists reasoned that if they could prevent feebleminded people from having children, they would be able to rid the country of feeblemindedness and crime in a few generations.

One of the foremost American proponents of this new theory was the eugenicist Henry H. Goddard, a psychologist at the New Jersey Training School for Feebleminded Boys and Girls.  In 1908, during a European tour, Goddard learned of a method of measuring intelligence with pencil-and-paper tests that was being pioneered by the French psychologist Alfred Binet.  Quickly translating Binet’s tests and applying them, without standardization, in institutions for juvenile delinquents, Goddard found that most law‑breakers tested at or below the “mental age” of twelve, which he immediately identified as the upper limit of feeblemindedness.

Goddard’s apparently definitive evidence that what ails criminals is weak intelligence was confirmed by other psychologists who administered intelligence tests in prisons and reformatories.  At the same time, officials at institutions for the feebleminded proclaimed that nearly all of their charges were inclined to criminal behavior.  The feeblemindedness theory of crime seemed to have been scientifically verified.

One result of this theory was a rapid expansion of the system of training schools for the feebleminded and their transformation into custodial institutions where people with mental retardation could be held for life.  Another result was the enactment in several states of “defective delinquent” laws that enabled authorities to hold accused and convicted offenders who seemed feebleminded for up‑to‑life terms, again for eugenic purposes.6

Advances in genetics and mental testing began undermining the feeblemindedness theory of crime about 1915.  Nevertheless, eugenicists continued endorsing it for many years.  For instance, in 1934 the criminologists Sheldon and Eleanor Glueck reported that most inmates of the Massachusetts reformatory for women were mentally defective.  They recommended that such women be held for life, irrespective of their crimes.


Multiple and Diverse Biological Theories:
ca. 1930-2000

Since the heyday of feeblemindedness theory, scientists have proposed a range of biological explanations of crime, some incorporating themes of the past, others striking out in new directions.

About 1915, some psychiatrists began translating the psychological concept of feeblemindedness into their own theory of psychopathy.  They portrayed the psychopath as “constitutionally inferior” but not necessarily feebleminded.  Moreover, although many of these theorists sympathized with eugenics, few claimed that psychopathy per se is inherited.

More in tune with earlier traditions was The American Criminal (1939), an anthropological study by Harvard professor Ernest A. Hooton that called for eugenic control of offenders.  A companion volume, Crime and the Man (1939), examined the anthropological characteristics of criminals by race and ethnicity, closing with a cartoon (sketched by Hooton himself) of a policeman hauling a criminal off to a prison labeled “Birth Control Clinic.”

Inspired by Hooton, in the 1940s Harvard psychologist William H. Sheldon launched the field of “constitutional psychology,” an attempt to correlate criminal tendencies with body types.  Like Hooton, Sheldon was a eugenicist.  His self-described aim was to make “a direct attack on our most deadly enemy—- careless reproduction.”

Nazi efforts to eliminate “degenerates” made eugenics disreputable.  However, research continues on biological factors in crime, and when it purports to identify factors that are genetic, it has distinctly eugenic implications.  In The Bell Curve (1994), for instance, Richard Herrnstein and Charles Murray argue that “IQ is substantially heritable” and that low IQ scores are strongly associated with criminality.

Some late twentieth-century theorists have speculated about links between criminal behavior and brain anomalies, while others have attributed criminality to abnormalities of the endocrine system.  Hormones are indicted by PMS (pre-menstrual syndrome) theorists, who posit a correlation between menstruation and violence in women.  For a while, XYY theorists claimed to have established an association between men with an extra Y chromosome and violent behavior. Recently, crime has been tied to deficits in levels of the neurotransmitter serotonin and to unusually small amounts of gray matter in the brain.  Returning to Richard Dugdale’s genealogical method, some scientists are again studying families for histories of violence and other psychopathologies.

As in the past, late twentieth-century biological theories of crime have tended to picture criminality as a sort of disease or physical abnormality.  Today’s theories are less deterministic than their predecessors, however; they speak of probabilities and of people who are “genetically at risk” rather than claiming that all people with a certain trait will become offenders.  And they are more likely than earlier theories to recognize the effects of interactions between people and their environments.

Biological theories offer just one type of explanation of crime; many other theories explain criminal behavior in social terms.  In this exhibit, we focus solely on biological theories, concentrating on their visual strategies.  This history of the sciences of criminal bodies is designed to encourage viewers to decode and analyze the rhetorical imagery of those sciences and to ponder assumptions about the boundaries between science and art.


1.   At about the same time, the first French psychiatrists embarked on similar work.

2.   This particular quotation is from a second essay by Rush, “Of Derangement in the Moral Faculties,” in Benjamin Rush, Medical Inquiries and Observations, upon the Diseases of the Mind (Philadelphia: Kimber and Richardson, 1812): 360.

3.   Benjamin Rush, “An Inquiry into the Influence of Physical Causes upon the Moral Faculty,” in Benjamin Rush, Medical Inquiries and Observations, 4th ed., Vol. I, 1786 (reprinted Philadelphia: M. Corey, 1815): 97.

4.   Many of the bad-family studies are collected in Nicole Hahn Rafter, White Trash: The Eugenic Family Studies, 1877-1919 (Boston: Northeastern University Press, 1988).

5.   Francis Galton, Inquiries into Human Faculty and Its Development, 1883 (reprinted. New York: AMS Press, 1973): 17, n. 1.

6.   Nicole Hahn Rafter, Creating Born Criminals (Chicago: University of Illinois Press, 1997).