Biology and Crime
• Early Theories of Biology
and Crime
• Modern Approaches
– Behavioral Genetics
– Biological Factors Related to
Crime
– Biosocial Theory
– Policy Implications
Early Biological Theories (1 of 2)
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Early history of criminology
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Many early criminologists were physicians
General idea = the presence of certain physical traits
makes criminal behavior more likely
Early Biological Theories (2 of 2)
1. Phrenology
2. Lombroso’s “born criminal”
3. Physical deficiencies
4. The XYY “supermale”
5. Somatotype theory
Phrenology
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Exterior of the skull reflects the mind
Bumps on the head indicate criminal
tendencies
Lombroso’s “Born Criminal” (1 of 3)
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Cesare Lombroso
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19th-century Italian physician
Led the movement from classical school to
scientific positivism
Major contributions
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Study of the individual offender and crime conditions
Application of statistical methods to data collection and
analysis, as well as multiple-factor analysis
Use of typological methods to classify and study
criminals and examine criminological phenomena
Lombroso’s “Born Criminal” (2 of 3)
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Atavism
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Criminals as evolutionary
“throwbacks”
Physical traits (Stigmata)
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Peaked nose (as bird of prey)
Sloped forehead, large jaws
Strong canine teeth (as with carnivores)
General hairiness of the body
Low foreheads
Lombroso’s “Born Criminal” (3 of 3)
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Types of criminals
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Insane
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Idiots, drug addicts, moral degenerates
Criminaloids
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Those who have less pronounced physical stigmata
Criminals by passion
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Passion (like love, hate, honor) fueled their criminal
rage
Physical Deficiencies
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Charles Goring
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Criminal behavior related to defective
intelligence
Earnest Hooten
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Criminals physiologically inferior
Physical traits
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Low foreheads
Pinched noses
Compressed faces
Narrow jaws
Somatotype Theory (1 of 3)
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Developed by William Sheldon (supported
by the Gluecks at Harvard)
Body build (somatotype) linked to:
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Behavioral tendencies
Temperament
Life expectancy
Susceptibility to disease
Somatotype Theory (2 of 3)
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Basic body types
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Endomorph
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Fat, soft, and round
Tend to be extroverts
Ectomorph
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Thin and wiry
Easily worried, sensitive, and introverted
Mesomorph (most criminals)
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Muscular
Gregarious, aggressive, assertive, and action oriented
Somatotype Theory (3 of 3)
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Explanations
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Those with muscular builds tend to enjoy the
physical activity involved in crime.
Mesomorphic body type may have an advantage
in the rough-and-tumble activities of street
crime.
Mesomorph is perceived as a threat and is
therefore more likely to be arrested and/or
incarcerated.
The XYY
“Supermale”
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Chromosomal abnormality
(extra Y chromosome)
▪ May be more likely to
engage in criminal
behavior (but not violent
behavior)
▪ Extremely rare
chromosome structure
(less than 0.1% of total
male population)
Policy Implications of Early Biological
Research
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Focused on single, direct cause of crime that
cannot be changed
Policy implication = Eugenics
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Remove these individuals from society through
forced sterilization, internment in camps, or death
Eugenics movement waned after WWII
The demise of early positivism
1. Poor theory
– Single biological trait as direct cause of crime.
2. Poor/biased research
– Any small criminal/non-criminal difference were
assumed to reflect the superiority of noncriminals
3. Dangerous policy implications
– Eugenics movement
Largely discredited by Sociologists by 1950.
Modern Biological Approach (2 of 2)
1. Behavioral genetics
2. Biological correlates of criminal behavior
3. Biosocial theory
4. Evolutionary theory (sociobiology)
Behavioral Genetics (1 of 5)
Can criminality be inherited?
Trying to separate nature (genes) from nurture
(environment)
▪ Family studies
▪ Twin studies
▪ Adoption studies
▪ Molecular genetics
Behavioral Genetics (2 of 5)
Family studies
▪ Early studies traced family history (Jukes)
▪ Modern studies look at parent’s crime
(Sampson and Laub)
▪ Findings: Parental crime consistently predicts
children’s criminal behavior.
▪ Criticism: Environment (poor parenting,
shared environment) could easily explain this
finding.
Behavioral Genetics (3 of 5)
Twin studies
▪ Compare monozygotic (MZ) and dizygotic (DZ) twins
▪ MZ twins have higher concordance rates than DZ
twins: Danish Study (Christiansen, 1979)
• MZ=52%
• DZ=22%
▪ Criticism:
▪ People may treat MZ twins more similarly
▪ MZ twins more likely to share friends (including delinquent
peers)
Behavioral Genetics (4 of 5)
Adoption studies
▪ Compare criminal record of adopted children
with their biological and adoptive parents.
▪ Findings: Children’s criminal behavior relates
more to biological parents.
▪ Criticism: Adoption agencies might have
biased placements.
Cross Fostering Analysis
Mednick et al. (1984)
Environment
Adoptive
Parents
Criminal?
YES
NO
Biological Parents
Criminal?
YES
NO
24.5%
14.7%
20.0%
13.5%
“Genetic” Effect
Behavioral Genetics (5 of 5)
Molecular genetics
▪ Isolates particular genes
that may relate to crime
– DNA
– Bases (A,T,C,G)
– Gene
Gene-linkage
– Hans Brunner Case as
“OGOD”
Human Genome Project
Many biological factors may contribute
to criminal behavior
1. Neurological factors
2. Autonomic nervous system
3. Biological harms
4. Hormones
Neurological Factors (1 of 2)
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Direct measures of the brain
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Prefrontal cortex
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Executive functions (e.g., cognition, attention,
impulsivity)
MRI and PET scans analyze brain structure and
activity
Differences in the frontal lobe exist between
criminals and noncriminal control groups
Neurological Factors (2 of 2)
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Neurochemical measures
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Neurotransmitters (like serotonin) allow cells to
communicate with each other.
Low levels of serotonin are sometimes linked
with impulsive and aggressive behavior
• Monoamine oxidase A (MAOA) gene implicated in
several studies
– Hans Brunner study
– Interaction between specific forms of the gene and
violence/crime (New Zealand study)
Autonomic Nervous System
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Controls how the body reacts to stimuli
(heart rate, gland secretions)
Some criminals have lower resting heart
rates than noncriminals.
Studies of skin conductance (sweat) yield
mixed results.
Criminals potentially have low levels of
arousal.
Biological Harms (1 of 3)
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Perinatal risks linked with criminality
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Smoking (cigarettes, marijuana)
Alcohol consumption (fetal alcohol syndrome)
Delivery complications
Low birth-weight children
More pronounced effect in unstable families
Biological Harms (2 of 2)
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Environmental toxins
Lead exposure
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Highly toxic substance (especially for young
children)
Found in lead paint and leaded gasoline
Can cause serious health and behavioral
problems
Linked to delinquent behavior
Biosocial Theory
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Combinations of environmental and
biological risk cause criminal behavior
1. Life-course-persistent offending
2. Personality-based theory
3. Female delinquency
Life-Course-Persistent Offending
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Developed by Terrie Moffitt
Adolescent-limited (AL) offenders
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Criminal behavior limited to adolescence
Life-course-persistent (LCP) offenders
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Chronic offending starts early in life
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Argue that LCP path is caused by neurological deficits
and ineffective parenting
Personality-Based Theory
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Hans Eysenck
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Personality traits driven by underlying biology
cause crime.
Children with low arousal will be difficult to
socialize.
In criminal families, low arousal might prevent
children from learning criminal behavior.
Female Delinquency
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Early onset of puberty is linked to criminal
behavior.
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Caspi et al. = This is true for girls in coed
schools, but not for those in all-girls schools.
Conclusion: Girls who start puberty early attract
the attention of older, crime-prone males, which
may lead to delinquency. Good example of a
biology x environment interaction.
Evolutionary Theory (1 of 2)
▪ Uses principles of evolution to explain modern
human behavior
▪ Research
▪ Rape
▪ “Cads and dads” theory
▪ Criticism
▪ Difficult if not impossible to test
▪ Evidence sometimes runs counter to predictions
Evolutionary Theory (2 of 2)
▪ Rape
▪ Evolutionary processes allow males who are pushy
and aggressive in the pursuit of sex to pass on
their genes successfully.
▪ “Cads and dads” theory
▪ Alternative strategies for reproductive success
▪ Cads—pretend caregivers who really want to
reproduce with as many females as possible
▪ Dads—invest time and energy to help nurture and
raise offspring
Summary
▪ Many biological factors appear to be related
to criminal behavior:
▪ Inherited
▪ Results of biological harm
▪ Biological factors contribute to criminality in
certain environmental circumstances.
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“Biosocial” Theories
Biological Theories Criticisms
▪ Ignores some types of crimes
▪ White-collar
▪ Organized
▪ Political crime
▪ Focuses on aggression or antisocial behavior
in children and street crime in adults
Policy Implications (1 of 2)
▪ Still fear of ethical problems
▪ Biology not necessarily destiny
▪ Provide unsound justifications for the control of
minority populations
▪ New eugenics
▪ Gene therapy
▪ Discrimination based on presence of biological risk
indicators
Policy Implications (2 of 2)
▪ The upside? Criminality as a public health
problem
▪ Prenatal care for at-risk mothers
▪ Strengthen environmental counterbalances for
children with biological risk indicators