Biological theories

1. Biological theories

2. Nature v. nurtureWhat’s presently accepted? • Inheritance & environment don’t “cause” but may “predispose” • Crime is a social definition -- Malum in se v. mala prohibita • Not all maladaptive behaviors are illegal • Behavior is affected by ... • Inherited characteristics • Inherited characteristics, affected by environment • Environment effects on health (injury, pollution, diet…) • General agreement that biology and environment interact • Sociologists, including criminologists, tend to minimize biological and psychological factors • But as we learn more about the human organism, more and more winds up being explained by chemistry

3. A trip through the past:body type (“somatotypes”) • Sheldon linked physique and temperament • Endomorph: Soft physique, relaxed and comfort-seeking temperament • Mesomorph: Muscled physique, active and assertive temperament • Ectomorph: Lean, frail physique, introverted temperament • Gluecks found correlation between mesomorph somatotype and aggressive/antisocial/uninhibited behavior

4. Family studies - Goring • Examined relationship between heredity, environment and length/frequency of imprisonment • Heredity  imprisonment? • Environment  imprisonment? • Findings • Environmental factors not correlated with imprisonment • Poverty, broken homes, nationality, birth order • Biological factors are correlated with imprisonment • Physical size (smaller, worse off) • Mental inferiority • Criminal family members

5. Criticisms of Goring and family studies • Failure to adequately measure environmental variables • Current data does not suggest that crime “runs rampant” in families • Difficult to control for environmental effects within families, as all are usually exposed to similar circumstances

6. Twin studies • Difficult to control environmental variables • So, control heredity • Fraternal twins: different eggs, different DNA • Can inherit different biological factors • Identical twins: one egg, same DNA • Biological factors the same • Look for similarities and differences in behavior • Similarities between identical twins can be hereditary or environmental; differences cannot be hereditary • If behavior of sets of identical twins is more alike than behavior of sets of fraternal twins, heredity may be important

7. Studies of identical twins -- Christiansen • 6,000 pairs of male twins • Male identical twins: 67 pairs where at least one was registered as a criminal. • In 36% of these pairs (n = 24) both were criminals • Male fraternal twins: 114 pairs where at least one was registered as a criminal • In 12% of these pairs (n=14) both were criminals • Higher concordance for serious crimes • Issue: Could higher concordance of behavior for identical twins be due to a more similar environment?

8. Twins reared apart • Similar environments might make identical twins act alike, so study identical twins reared apart • Grove (32 pairs separated shortly after birth); Christiansen (8 pairs). • Both found evidence that antisocial behavior can be inherited • Walters - 1992 meta-analysis of 14 twin studies • Considered sample size, quality of research design • Support for hereditary basis to criminality • May be difficult to control for environmental effects

9. Adoption studies • Attempt to control for environmental effects • Hutchings and Mednick -- biological fathers appear to influence boys’ criminality

10. Mednick -- cont’d • Number of court convictions of biological parents (not adoptive parents) influences youth criminality, but only for property crimes • Other influencers: • Socioeconomic status of biological and adoptive parents • Personality disorders of biological parents • Number of placements before adoption • Criminality of biological and adoptive fathers interacts • Issues with adoption studies • Low sample sizes • Recent studies found link between heredity and behavior only for minor and property crime (far more frequent than violent crime) • Adoptive parents often more law-abiding than general population

11. Brain chemistry • Neurotransmitters • Chemicals that transmit electrical impulses in the brain • Levels affected by medication, diet, drug use, stress • Imbalance may promote aggressive or compulsive behavior • Violence, drug use • Hormones • Testosterone: Documented role in animal aggression, effects found in human research • Issues • Causal order: Aggression may be the cause (not the effect) of high levels of hormones • Booth and Osgood study • Association between testosterone and adult deviancy • BUT – effect of high levels mediated by social integrationHigh levels  lack of social integration  aggression

12. Central nervous system (CNS) • Brain and spinal cord • Cerebral cortex - outer portion of the brain • Four lobes (frontal, temporal, parietal, occipital) • Frontal and temporal lobes control goal-directed behavior, impulses and emotions

13. CNS and criminal behavior • Some evidence that abnormalities in the lobes may be associated with violent and sexual offending • Frontal dysfunction may be associated with violent offending • Temporal dysfunction may be associated with sexual offending • Violent sexual offenders may have both dysfunctions • Issues • Research methodology - no sampling (with a hammer, everything’s a nail) • Precise path to offending is unknown

14. Autonomic nervous system (ANS) • Controls involuntary functions: Blood pressure, heart activity, intestinal activity, hormone levels • “Fight/flight” situations: ANS prepares body to respond • Blood from stomach to muscles • Increases respiration • Stimulates sweat (increases electrical conductivity of skin)

15. ANS - continued • Anxiety (e.g., conditioned fear of being punished for telling a lie) is basis for lie detection • Anxiety may be the primary socializing agent for children • They behave properly to avoid anxiety of punishment • Hypothesis that defective response can interfere with socialization • Antisocial persons might be more difficult to “condition”, so they are less likely to fear punishment

16. Environmental-biological factors:Drugs and alcohol • Alcohol in lower doses increases aggressive behavior, especially in males • Marijuana may reduce but does not increase aggression • Opiates may reduce aggression • Chronic use may increase aggression • Withdrawal from opiates may also increase aggression • Methamphetamine, PCP and LSD may increase aggression • May be especially true for those predisposed to violence • Police anecdotes about extreme violence and strength displayed by persons high on Meth and PCP • No direct evidence of effect of cocaine on violence • Association between violence and areas where rock cocaine is used (inner cities) • Note - “rock” cocaine is much more concentrated

17. Other environmental-biological factors • Lead in diet may affect brain functions • May cause hyperactivity and antisocial behavior in children • Head injury with brain damage may cause violent behavior • Decrease cognitive and social skills • Headaches and irritability • Damage frontal and temporal lobes, increasing anxiety, anger and hostility • Delivery complications correlated with violent offending • Particularly when parents had psychiatric problems