Criminal Behaviour - Lecture 2b Theories of Crime - Biological & Evolutionary Explanations student
Theories of Crime
Biological & Evolutionary Explanations
Presented by Dr. Shannon Vettor
Goals of Today's Class/Readings
Early theories of crime
Biological explanations of criminal behavior
Evolutionary theories related to crime
Criteria for a Good Theory
Parsimony: Offers simple explanations that effectively cover a wide range of phenomena, avoiding unnecessary complexity.
Causative Statements: Clearly identifies mediators and moderators that influence the relationship between variables.
Empirical Basis: Supported by data that accommodates new findings and evolves as more research is done.
Falsifiability: Must be testable against evidence and can be proven wrong if new evidence arises.
Interdisciplinary Compatibility: Should connect and make sense within various fields of study, enhancing understanding across disciplines.
Respect for Diversity: Considers diverse factors including gender, ethnicity, and culture in its explanations and recognizes that different groups may experience crime differently.
Mediation and Moderation in Theories
Mediation: Explains how and why a certain relationship occurs by identifying underlying processes.
Moderation: Illustrates when and for whom an effect occurs, highlighting contextual factors that influence outcomes.
Historical Theories of Crime
Franz Gall (1758-1828):
Introduced Phrenology, the belief that the shape and bumps of the skull could indicate personality traits and behaviors.
Example: A bulge above the ear might suggest a tendency toward destructiveness and aggression.
Cesare Lombroso (1835-1909):
Advocated the idea of Criminal Man (1876) which proposed that certain individuals are born predisposed to antisocial behavior.
Introduced the concepts of homo delinquens (criminal humans) vs. homo sapiens and the idea of Atavisms, which are primitive traits exemplified in physical characteristics.
Identified Physical Abnormalities Linked to Crime, such as a flattened nose, large ears, twisted lips, and sloping forehead, indicating a correlation between physical features and criminal behavior.
Criminal Taxonomy by Lombroso
Profession: Crime as a trade or profession.
Juridical: Crime committed out of impulsivity.
Passion: Crimes motivated by intense love or emotional states.
Criminaloids: Crimes influenced by poor role models and social environment.
Born Criminal: Concept where crime is viewed as a predisposition present from birth.
William Herbert Sheldon, Jr. (1898-1977):
Developed Constitutional Psychology linking physical characteristics to personality traits, proposing three categories of body types (somatotypes):
Endomorph: Characterized by a fat and soft physique; sociable and relaxed.
Mesomorph: Muscular, adventurous, and risk-taking personality; often associated with aggressive behavior.
Ectomorph: Thin, shy, reserved individual, less prone to criminal activity.
Biological Theories of Crime
Genetics and Crime: Examining hereditary aspects of criminal behavior, suggesting that genetics play a role in criminal tendencies.
Behavioral Genetics: Focuses on studying twins and adoption to distinguish genetic effects from environmental ones.
Molecular Genetics: Investigates neurochemistry and genetic variations related to criminal behavior.
Twin Studies
Research compares concordance rates of crime between identical (MZ) and fraternal (DZ) twins.
Lange (1929) initiated studies showing significant differences:
MZ twins exhibited a 77% concordance rate compared to only 12% for DZ twins.
Recent studies (Raine, 1993; Joseph, 2001) continue to confirm that MZ twins display higher concordance rates in criminal behavior, although criticisms exist over potential biases, small sample sizes, and the role of environmental factors.
Adoption Studies
Examine crime rates between biological and adoptive relatives, reinforcing the idea of genetic influence in crime.
Higher concordance rates observed between biological parents and their children underscore the genetic heritability of criminal behavior.
Genetic Influences in Criminal Convictions
Mednick et al. (1984): Studied conviction rates among non-familial adopted children in Denmark, finding notable correlations with biological relatives.
Rhee and Waldman Study (2002):
Analyzed results from 10 adoption studies and 42 twin studies, finding 41% heritability of crime, 16% shared environment, and 43% non-shared environment.
Molecular Genetics - XYY Syndrome
Jacob et al. (1965) proposed a link between violent crime and the XYY syndrome, which posits that males with an extra Y chromosome may have a predisposition to aggressive behaviors, though evidence remains mixed regarding its prevalence among criminals.
Understanding the 'Warrior Gene'
MAOA gene linked to aggression and crime, with the low activity version associated with an increased likelihood of engaging in criminal behavior.
A significant study by Caspi et al. (2002) tracked children into adulthood, examining how childhood maltreatment interacts with genetic predispositions to influence future criminal activity.
Neurotransmitters and Crime
Neurotransmitters serve as key chemical messengers in the brain that can influence behavior in profound ways.
Serotonin: Associated with impulse control—low levels can lead to impulsivity and aggressive behaviors.
Dopamine: Relates to pleasure and rewards, with mixed results regarding its association with aggression.
Norepinephrine: Linked to stress responses and potential aggression triggers.
The Brain and Crime
Key Brain Structures Involved in crime include:
Frontal Lobe: Involves executive functions such as planning, controlling impulses, and decision-making.
Limbic System: Responsible for processing emotions and storing memories, impacting emotional responses that may lead to criminal behavior.
Neuroimaging Studies:
Use technologies such as MRI and CT for structural insights and PET and fMRI for functional activity analysis of the brain.
Notable studies have compared brain activity and structures between criminals and non-criminals to identify underlying neurological factors.
Prefrontal Cortex and Aggression
Injury to the Prefrontal Cortex may lead to increased impulsivity and aggressive behaviors (example: Phineas Gage, who experienced notable changes in personality following an injury).
A study by Raine et al. (1997) showed that murderers claiming insanity had less prefrontal activity compared to noncriminals, indicating a potential neurological basis for impulsive criminal behavior.
Criticisms of brain research stress that studies focus primarily on violent offenders, leading to small sample sizes and correlational data, which raises questions about direct causation.
Evolutionary Theories of Crime
These theories examine human psychology through the lens of Darwinian evolution, positing that behaviors leading to crime may have been shaped by natural selection over time.
Natural Selection Process:
Genetic mutations can introduce potential adaptations that may enhance reproductive success, while selection pressures determine if these adaptations survive across generations.
Evolutionary Psychology
Focuses on how mental processes are shaped by evolutionary forces, enhancing survival and reproductive success.
Reflects distal rather than proximal explanations for crime, emphasizing historical factors rather than immediate causes.
Criticisms of Evolutionary Psychology
Critiques include determinism arguments, and the misconception that natural selection acts with conscious intent, rather than being a blind process.
Application of Evolutionary Theory in Forensic Psychology
Hypothesizes that ancestral selection pressures lead to psychological mechanisms manifesting as criminal behavior under modern circumstances.
Life History Theory
Explores strategies our ancestors utilized for survival and reproduction, which are reflected in today’s behaviors, especially in risky or criminal actions.
Balancing parental investment and mating efforts significantly shapes criminal behavior in terms of resource allocation.
Life History Theory & Antisocial Behavior
Childhood environments can significantly link to adult aggression and criminality, indicating the importance of early life experiences.
Frequency Dependence Selection: Suggests that psychopathy may arise as an adaptive strategy when certain conditions prevail in population dynamics.
Male-Male Competition and Homicide
Threats to reputation and social status among males may trigger violent responses, contributing to homicide rates, particularly in competitive environments.
Gender Differences in Crime
Examines differences in psychological mechanisms between males and females regarding crime and differing parental investment strategies, highlighting varied motivations and behaviors in criminology.
Sexual Coercion and Evolution
Investigates how evolutionary pressures may influence sexual behaviors and responses to mating opportunities, shedding light on underlying motivations for certain types of crime.
Conclusion on Theories of Crime
Prepare for next week’s discussions on Learning and the Environment theories of crime, further expanding our understanding of criminal behavior across diverse contexts.