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Chapter 2

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Department
Psychology
Course
PSYC39H3
Professor
David Naussbaum
Semester
Fall

Description
Chapter 2 – Theories of Crime: Biological and Evolutionary Explanations INTRODUCTION Ancestral environment: the hunter-gatherer era from which most of our current-day adaptations are hypothesized to evolve What makes a strong theory?  a theory is an explanation of a phenomenon A strong theory is: 1. parsimonious 2. identifies the causal mechanisms and corresponding mediators and moderators underlying the phenomenon of interest 3. testable and falsifiable 4. based on empirical data and changes in response to new data 5. interdisciplinary compatibility 6. respects gender, ethnicity and culture BACKGROUND Historical Context  Franz Gall  phrenology; a r/l b/w the shape and size of a person’s head and behavior  Gall’s student, Spurzheim, used phrenology to explain why 30 women killed their kids  He said they had an underdeveloped part of the brain responsible for loving children  Sp failed to include a comparison group (women who didn’t kill their kids)  Lombroso began comparing criminals to normal people  He argued criminals possess distinctive physical features  atavisms  Criminals were evolutionary throwbacks who have more in common with Neanderthals  Although his theory lost their gusto, Lombroso is the “father of criminology” Darwin  Published On the Origins of Species in 1859, 17 yrs before Lombroso published The Criminal Man  Humans evolved from ancestral species via natural selection  His cousin Galton misused Darwin’s work;  Galton founded eugenics – the theory responsible for the forced sterilization of thousands of ppl deemed unfit to reproduce in early part of 20 century; also for the forced abortion, sterilization and death of ppl under Hitler’s regime RESEARCHING BIOLOGICAL EXPLANATIONS OF CRIME  Behavioral genetics uses twin methodology to see if identical twins are more likely to commit crime than non-identical twins  Molecular biologists compare the genetic makeup to look for distinct genetic differences  Neurochemical approaches look at how genes actually express themselves in terms of the brain’s neurotransmitter systems  Computer tomography (CT)  functions of the brain Defining crime is a hard task  Some researchers compare “normal” ppl to those with antisocial personality disorder (ASPD), conduct disorder, psychopathy; others have used measures of aggression or composite indices of antisocial behavior obtained via self-report or parents/teachers  Researchers often define crime using current legal definitions and see if bio factors correlate or predict official criminal offending in the form of arrest or convictions  Targets of study are varied (some focus on males some focus on females)  Research methods and participant pools are vast and complex Genetics and Crime – Twins, Adoption and Molecular Genetics Twin Studies  Behavioral genetics relies a lot on the study of twins and adoptions, can help separate genetic from environmental influences  Every human shares about 99% of DNA sequence  The percentage is fixed for basic similarities (two arms, one heart, two eyes)  BG focuses on the remaining 1% that is free to vary  Monozygotic (MZ) or identical twins are genetically identical; the share 100% of their genes; the 1% that is free to vary for other humans is 100% the same for MZ twins  Dizygotic (DZ) twins/fraternal share on avg 50% of that 1% that varies Research  Sample of MZ and DZ twins, both raised by bio fams, get an estimate of criminal behavior via self-report  Next, record the number of times each set of twins (crim and non-crime) was identified as criminal  The frequency gets converted into a concordance rate; calculated separately for MZ and DZ and then compared  Rate of 30% for DZ means if one of the DZ twins was “criminal” 30% chance the other DZ twin is criminal; same for MZ  Genetic contribution to crime is inferred if rates are higher among MZ than DZ  Concordance rates are converted into heritability coefficient – represents the proportion of phenotypic variance; attributed to genetic variation  Now, more sophisticated stat methods like biometric modeling estimate h. coefficients  Statistical modeling estimates 2 types of environmental factors: 1) shared environmental factors (aspects of environment shared by family, like living in poverty); and 2) non- shared environmental factors (exposure to difference peer groups or differential treatment by parents)  A common criticism of stats studies is that it may overestimate or underestimate the genetic contribution 1. more similar environments for MZ (same clothes, toys, learning opportunities) than DZ, artificially inflating the genetic contribution; - some twin studies have solved this problem by performing “natural experiments” where MZ twins are separated at birth and reared independently 2. heritability estimates for MZ twins may be confounded by prenatal factors that aren’t necessarily genetic - earlier twin studies were criticized for using small sample sizes and for being subject to political influence Adoption Studies  in the parent-offspring paradigm, concordance rates (or correlations) b/w adoptive parents and adoptees’ antisocial behaviour are compared to c. rates b/w biological parents and adoptees  if the c. rates are higher for the bio parents and adopted offspring than adoptive parents and adopted, genetic contributions are inferred  cross-fostering paradigm, whereby kids who had bio parents who were criminal or non- and adoptive parents who were crime or non-  in the sibling-offspring paradigm, c. rates b/we adoptive siblings are compared with concordance rates b/w biological siblings  in a study by Mednick, the highest level of criminality (24.5%) was observed if both sets of parents – bio and adoptive – had criminal records  the study shows genes play a role in explaining crime and shows importance of environmental effects Limitations: 1) Generalizability – adoptees have higher rates of ASB; 2) Environments of adopted offspring more advantageous, thereby reducing shared environmental effects due to restricted range  Rhee and Waldman (2002) completed the most comprehensive meta-analytics review by aggregating the results of 10 independent adoption samples and 42 independent twin samples  In sum, across all studies, the variance in ASB: heritability, .41; shared env, .16, and non- shared env, .43  They also examined moderators that impact the size of the heritability coefficient 1. Zygosity determination (self report vs. blood typing) 2. Assessment method (parental vs. teacher-and-self vs. criminal records) 3. Operational definition of ASB (diagnoses of conduct disorder and antisocial personality disorder vs. legal definitions vs. overt aggressive behavior – one uses a weapon frequently) 4. Sex of the participants 5. Age  Genetics and environment both contribute to variance in ASB  The gene-crime link is most likely not a direct conduit but rather meditational effects predispose a person to engage in ASB  Pathways to ASB are not usually direct, nor uni-dimensional  ASB often results from a series of complex interactions b/w numerous factors that in and of themselves may seem benign, but in combination produce devastating consequences  Genetics may reduce or magnify the effects of environmental risk factors  Behavioral geneticists are now asking if there are interactive effects between genes and the environment: IS there a “gene” by “environment” effect?  experiences of maltreatment increased the probability of receiving a conduct disorder diagnosis by 1.6% among “lowest genetic risk” children – i.e., MZ co-twin did not have CD diagnosis  the probability of receiving a conduct disorder diagnosis increased to 23.5% among “highest genetic risk” kids – i.e., MZ co-twin had CD diagnosis Molecular Genetics Research  twin and adoption studies show a clear link b/w genetics and ASB  however, the actual functional gene(s) involved haven’t been identified  main function of a genes is to produce proteins that are made of amino acids (the basic building blocks of life)  proteins are responsible for phenotypic expression of our genotypes  faulty genes produce too much or too little of a particular protein  human genes stored in 46 chromosomes (23 pairs)  one pair is the sex one – males XY and female XX  X-linked genes are on the X chromosome  Caspi (2002) published the first ground-breaking study demonstrating an interaction between a specific gene and a risk factor – childhood maltreatment  They wanted to know how a low-activity version of the monoamine oxidase A (MAOA) gene may or may not intensify the effect of maltreatment  MAOA located on the X chromosome  so it’s sex-linked  Responsible for encoding the MAOA enzyme, which is responsible for metabolizing or breaking down brain NT’s like norepinephrine (NE), serotonin (5-Ht) and dopamine (DA); all of these NTs are implicated in aggression and forms of ASB  the low and high activity versions of the MAOA gene are the result of polymorphism  Caspi tested MAOA genes by environment interaction  Epidemiological study  Followed an entire cohort from birth until age 26 in New Zealand town of Dunedin  There was a strong gene by environment interaction across all four measure of ASB – conduct disorder, violent convictions, violent disposition, and antisocial personality disorder symptoms  Over 80% of youth with low MAOA activity and severely maltreated had CD  However, only 40% with high MAOA activity plus severe maltreatment had CD  Maltreatment has deleterious effects, they were exacerbated by the presence of a low- activity MAOA gene  There’s increasing evidence that the low-activity version of the MAOA gene, the “warrior gene” plays a big role in the expression of ASB, particularly aggression and violence  The low activity MAOA gene only expresses itself in the presence of certain environmental cues like childhood abuse or provocation Neurochemistry and Crime – Hormones and Neurotransmitters Hormones and Crime  Endocrine system governs more than 50 hormones in the human body  Hormones regulate metabolism, growth, development; also impact behavior  Testosterone is a steroidal hormone within the family of androgens  Develops and maintains male primary (penis and testes) and secondary sexual characteristics (deepening of voice, facial hair, muscle mass)  Two earlier meta-analyses – the r/l b/w testosterone and aggression is positive yet weak  Two factors moderated the effect: age and time of day  Testosterone levels fluctuate more in the morning, stabilizing in the afternoon/evening  Vast majority of these studies were correlational in nature and few if any shown that testosterone levels are either causally related to or predictive of future aggression  Aggression actually causes testosterone levels to increase or some third, mediating variable(s) is accounting for the effect  Physical chemical castration studies have shown that sexual re-offending is reduced in offenders who have undergone chemical and/or castration vs. those who did not  Results suggest r/l b/w testosterone and sexual aggression may be more than correlational ***Box 2.1 pages 40 Neurotransmitters and Crime  Neurons transmit instructional signals from one part of the body to another  NTs play a big role in this communication process  Presynaptic is the sender, and uses its axon’s synaptic terminals to transmit the message to the postsynaptic (receiver)  Postsynaptic receives the msg using dendrites  There are gaps (or synapses) b/w the pre and post  Some synapses are electrical, some chemical  An electric signal goes across the Presynaptic cell but can’t cross the synaptic cleft w/o becoming chemical  The thing that converts the electric signal to chemical is the neurotransmitter  NTs are stored in the synaptic vesicles Serotonin (5-HT)  Important for behavioral inhibition and mood regulation  Produced from the essential amino acid, tryptophan  Tryptophan not produced from body, so you have to get it from food (turkey, chocolate)  Since 1959, research shows there is a link b/w a malfunctioning serotonin system and impulsivity, irritability, and aggression (towards self and others)  Cerebrospinal fluid (CSF) studies are the most reliable way to measure serotonin levels  Meta-analytic review showed on avg, 5-Ht levels (measured with CSF 5HT metabolites) were lower among antisocial individuals  The effect even more pronounced for ppl under age 30 vs. over 30; The effect did not change as a fn of gender, target of violence, history of suicide, or alcoholism  In addition to being correlational in nature, the vast majority of studies included in the meta-analysis were based relatively on small non-random samples (e.g. less than 30)  High levels of 5HT in the blood indicate low 5HT in the brain  Moffit’s cohort is representative of a population  The results confirmed a moderate (positive) correlation b/w blood 5HT levels and violent criminal behavior for men but not women  The results did not vary as a fn of whether or not criminal behavior was measured officially or via self-report  The research suggests at the very least, there’s a correlational link b/w a malfunctioning serotonin system and aggression  Studies that artificially manipulate the level of tryptophan and then examine aggression, suggest a causal link; this research is preliminary and requires replication  Other research shows low levels of 5HT increase impulsivity (a known correlate of aggression)  Linnoila 1983, suggests that 5HT may exert its influence indirectly on aggression through the mediator of impulsivity Dopamine  Release of dopamine causes feelings of pleasure that accompany factors like sex, love  It can be triggered artificially with illicit drugs, alcohol, nicotine, some of which are known to increase aggression  Unfortunately, research is sparse compared to 5HT  It is also mixed, with both high and low levels of dope related to aggression  One hypothesis posits that individuals with low levels of dope require greater levels of stimulation to experience pleasure – hence more likely to get addicted to drugs  Regulates NTs including 5HT and norepinephrine  It’s possible dopamine exerts its influence indirectly via these NTs Norepinephrine  Norepinephrine signals the body to react to short-term stress by increasing heart rate and BP  limited research suggests high levels of NE are correlated with aggression  the finding is supported by the finding that certain drugs that reduce NE levels also reduce aggression; but further research needs to be done Psychophysiology and Crime  these theories try to link measures of autonomic response (heart rate, skin response) to various measures along the antisocial spectrum  Electrodermal activity (EDA) measure the amount of electrical current b/w two points on the skin; changes in electrical activity from sweating recorded by a polygraph  Increases in HR an EDA related to general emotional responses like fear, anger, anxiety Gray’s Arousal Model  Based largely on animal models  He hypothesized that personality, learning, motivation and emotional responses are largely governed by the behavioral activation system (BAS) and behavioral inhibition system (BIS)  The BIS is an avoidance system; stops behavior in the face of punishment; “I’m not gonna kill him b/c I don’t wanna go to prison.”  The BAS is reward-seeking; “If I punch John for flirting with my girlfriend I’ll feel happy.”  While the BIS is linked to anxiety, the BAS is linked to impulsivity and sensation- seeking behavior  Antisocial individuals have underactive behavioural inhibition systems, and are more fearless, less anxious, and less responsive to aversive cues  The fearlessness manifests in autonomic responses like low resting HR or low EDA  AS ppl have underactive BAS and thus prone to sensation-seeking and impulsive tendencies that lead to antisocial behavior  Rest: HR/EDA measured in the absence of stimuli  Task: HR/EDA measured in the presence of a stimuli (listening to a tone)  Reactivity: HR/EDA measured before and after a stimuli  Stimuli may also be neutral or aversive Lorber (2004)  Used meta-analytic framework, summarized the results of 95 studies  At most, there is a small effect for the relationship b/w HR and EDA and various conceptualizations of antisocial behavior (e.g. aggression, psychopathy/sociopathy, conduct problems);  This small effect most evident for psychopathy when EDA is used as the measure of autonomic arousal (regardless of whether the paradigm involved rest, task, or reactivity)  Psychopathic ppl show deficits in their BIS  Many of the studies were correlational and it’s hard to ascertain what came first: did a faulty BIS lead to psychopathic tendencies? Or did psychopath tendencies lead to faulty BIS?  Heart-rate level is a medium-sized correlate of antisocial behavior in children  Cohen d’s ranged from -0.43 in the resting HR to -0.76 in the reactivity)  Ortiz and Raine (2004) included 5 studies that show HR is predictive of future ASB  While measure of autonomic arousal are small or possibly moderate correlates of ASB, the predictive and/or causal status requires more research The Brain and Crime – Neuroimaging and Neuropsychology (p. 46) Brain Imaging – direct physical means  Examines the structural and functional characteristics of the brain (blood flow, glucose metabolism – the brain’s primary energy source)  Brain structure studied with MRI and CT  Brain function studied with PET and SPECT  More recent studies have compared brain function while participants are engaged in cognitive activity (such as when viewing emotionally negative pictures)  Raine and Yang (2006) say these studies help in summarizing results and provides an integrated conceptual framework  Raine and Yang (2006) hypothesized that damage to the brain areas responsible for moral reasoning and emotional regulation result in an “antisocial tendency”  Manifests in ways ranging from vilonet and sexual offending to psychopathic tendencies  Structural/functional deficits in 4 areas of the brain: 1. The frontal lobe – higher order functions like cognitive reasoning, planning, patience 2. Temporal lobe – production and inhibition of aggression (amygdala for emotional and fear; hippocampus for memory, learning and emotion regulation) 3. Parietal lobe – integrates sensory info related to movement and space 4. Cingulated gyrus – surrounds the corpus callosum (joins left and right hemispheres)  The limbic system  emotion and autonomic expression of emotion – faster heartbeat, faster respiration; basic drives like sex, hunger, thirst, “fight or flight” response Raine and Yang made several conclusions 1. Damage to pre-frontal lobe is the most replicated brain imaging abnormality found in offenders to date 2. Structural/functional damage to the limbic system (amygdala and hippocampus) and the temporal lobe are implicated in antisocial behavior 3. No single brain structure is ultimately necessary for the development of antisocial behavior; rather there are multiple potential contenders, and as the number of deficits increase, so does the probability of antisocial behavior  The research is not flawless - It is built on small samples of incarcerated offenders (sex and violent ones) without non-criminal comparison groups Neuropsychology  Neuropsyc
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