Forensic Psychology Flashcards
What does ‘forensics’ refer to?
Relates to the application of scientific methods and techniques to legal proceedings and the investigation of crime.
What is forensic psychology?
The practice of psychology applied to the law.
What is offender profiling? What is the main aim? When is it used?
An investigative tool that is intended to help investigators (the police) accurately predict the characteristics of unknown offenders.
-The main aim is to generate hypotheses about the probable characteristics of the offender (age, gender, background, occupation etc…) in order to narrow down the list of likely suspects.
-It is rare and professional profilers will only be called in to work alongside the police for serious and/or high-profile murder and rape cases - not used for less serious crimes.
What idea is offender profiling based on? What does it assume?
The idea that you can make assumptions about the characteristics of an offender by analysing the characteristics and particulars of the offence they commit.
-Assumes that crime is not random.
-Assumes that offenders have a distinctive way of committing crimes - ‘modus operandi’ (way of working).
-Assumes that offenders have a stable set of characteristics that will remain so over time - the principle of behavioural consistency.
What are the 2 approaches to offender profiling? What do they both involve?
1) Top-down approach - used in America.
2) Bottom-down approach - used in Britain.
-Although methods vary, the compiling of a profile in both approaches will involve the careful scrutiny of a crime scene and the analysis of other evidence (police reports, witness reports, crime scene photos, pathology reports etc…).
What is the top-down approach? How does it work? What is the basic premise?
The top-down approach (or the American approach) - where profilers start with a pre-established typology and work downwards to apply this to the crime scene and witness accounts in order to assign an offender to one of two categories/typologies.
-Starts with the big picture about the likely offender and then fills in the details.
-Attempts to fit the crime under one of the pre-established typologies based on the crime scene - hence top-down.
-The basic premise for this approach is that information left at the scene of a crime feeds back to the type of offender and tells us about their everyday behaviour - i.e how they offend may be consistent with parts of their life or everyday behaviour (not literally).
-The purpose of the approach is to detect signature aspects of the crime and similar patterns of modus operandi.
-Data can then be entered into a database and continually compared against other entries in relation to certain aspects of the crime.
How did the top-down approach originate? What research was conducted?
Originated in the USA as a result of work carried out by the FBI in the 1970’s.
-The FBI’s Behavioural Science Unit carried out in-depth interviews (qualitative data) with 36 sexually-motivated murderers - including Ted Bundy and Charles Manson - asked them about triggers and early warning signs.
-From the interview responses, as well as a thorough analysis of the details of their crimes, the offenders of serious crimes were categorised into organised and disorganised offenders (‘organised-disorganised’ typology) - each with certain characteristics.
-The characteristics of an offender could then be predicted by matching a crime scene to a pre-established typology.
What type of data is the top-down approach based on?
Top-down approach based on qualitative data.
What are the 2 types of offender?
1) Organised
2) Disorganised
-Based on the idea that the modus operandi of an offender generally correlates to a set of social and psychological characteristics.
What is an organised offender? What are the characteristics of an organised offence? What are the likely characteristics of an organised offender? What is their post-offence behaviour? Who is a classic example of an ‘organised’ killer?
An offender who shows evidence of planning, targets a specific victim and tends to be socially and sexually competent with above average intelligence.
-Planning is the key.
Offence (murder) characteristics:
-Planned/premeditated - e.g weapon hidden or materials brought to dispose of the victim’s body.
-Little evidence left at the scene - e.g might wear protective clothing to prevent blood splashes or DNA being left at the scene.
-Signs of self-control - e.g only stabbed once to kill, rather than inflicting multiple unnecessary wounds.
-Victim a targeted stranger - seeks to control them.
Likely offender characteristics:
-Above average IQ.
-Skilled occupation.
-Socially and sexually competent - charming.
-Married/cohabiting.
-Geographically mobile.
-Anger or depression at the time of offence.
-Likely kills after some sort of critical life event - e.g Ted Bundy’s girlfriend broke up with him.
Post-offence behaviour:
-Returns to the crime scene.
-Volunteers information.
Example - Ted Bundy:
-During the 1970’s, Bundy raped, tortured and brutally murdered over 30 women across 7 states.
-Bundy was charming and highly intelligent - traits he used to win the trust of his victims.
-While a student, Bundy had a serious relationship with a young woman who ultimately broke up with him - this was a pivotal moment in his descent into becoming a serial killer.
-Many of Bundy’s later victims resembled his girlfriend.
What is a disorganised offender? What are the characteristics of a disorganised offence? What are the likely characteristics of a disorganised offender? What is their post-offence behaviour?
An offender who shows little evidence of planning, randomly selects a victim and tends to be socially and sexually incompetent with lower-than-average intelligence.
-Impulsivity and recklessness is the key.
Offence (murder) characteristics:
-Unplanned/spontaneous - e.g driving in their car and see a potential victim.
-Evidence left at the scene - little attempt to hide.
-Minimum use of self-control or signs of constraint - e.g smashes window, rather than carefully removing a pane of glass.
-Victim randomly selected.
Likely offender characteristics:
-Lower-than-average IQ.
-Low skilled occupation or unemployed.
-Socially and sexually incompetent.
-Lives alone.
-Often lives and works near the crime scene.
-Fear or confusion at the time of the offence.
-Physically or sexually abused in childhood.
Post-offence behaviour:
-Returns to the crime scene to relive the offence.
-May keep a diary or the news articles of the incident.
What are the 4 stages of constructing of an offender profile using the top-down approach?
Constructing an FBI profile:
1) Data assimilation - information and evidence from multiple sources is gathered and reviewed (i.e police reports, witness reports, crime scene photos, pathology reports).
2) Crime scene classification - classified as either organised or disorganised.
3) Crime reconstruction - hypotheses in terms of the sequence of events and the victim’s behaviour are generated.
4) Profile generation - hypotheses related to the likely offender in terms of their demographic, physical characteristics and behavioural habits are generated - always compared to the typologies. Data can then be entered into a database and continually compared against other entries in relation to certain aspects of the crime.
The key thing with the top-down approach is that the typologies are pre-established and then applied to fit the crime scene - the crime scene only informs a pre-established category of profile rather than it building an independent profile in its own right.
What are the strengths and limitations of the top-down approach?
Strengths:
-Enormously influential as the first systematic approach for profiling offenders in serious crimes - adopted by many law enforcement agencies all over the world.
-Allows offences to be linked by offender typologies, thus facilitating predictions about the timeframe and nature of the next attack.
-Challenged the stereotype that investigators may have held about serious offenders being one thing - e.g Clarke and Morley (1998) interviewed 41 convicted rapists responsible for over 800 offences - found that they were typically average men living in normal family circumstances and in skilled employment (contrary to the stereotype of an inadequate loner).
Limitations:
-A typological approach assumes that offenders are one thing or the other and that this is stable over time - i.e behavioural consistency. Situationist psychologists argue that people’s behaviour is much more driven by the situation rather than by personality or the type of offender they are.
-Wilson et Al (1997) - suggests that most offenders show both organised and disorganised criminal behaviour and may shift between the, from crime to crime - so more of a continuum.
-Hypotheses generation subjective. Different profilers may reach different conclusions from the same evidence.
-Cannot establish a suspect in its own right - can only provide an outline or ‘sketch’ of the type of offender. Could result in innocent parties being implicated or arrested.
-Small and exclusive sample - the methods and motives of the 36 interviewed are of a very rare type of offender - may not be able to generalise to other offenders.
-Can only be applied to sexually motivated murder - although can be adapted to burglary in some cases. Canter et Al criticised the sample for its size and lack of randomness.
-Not scientifically verifiable - the vagueness of the profiled can lead to the ‘Barnum effect’, where the personality criteria are general enough to be applied to anyone.
-No ethical standards for the practice of profiling.
What is the bottom-up approach? Who developed it How does it work? What is the basic premise?
The bottom-up approach (or the British approach) - where profilers start with the evidence at the crime scene and work up to develop hypotheses about the likely characteristics and background of an offender by systematically analysing evidence.
-Developed by David Canter (1990) - said profiling needs to be scientific.
-Doesn’t begin with fixed typologies or theories - unlike the top-down approach.
-Starts with small details (the raw data) which are rigorously scrutinised to build up the bigger picture of a conclusion about the offender - e.g physical evidence - forensics, DNA.
-Assumes that offenders leave a ‘psychological fingerprint’ of unique and consistent behaviour.
-Data-driven so doesn’t rely on a subjective interpretation of an offender or crime scene - uses scientific and quantitative data - e.g forensics and DNA.
-This data is then inputted into a database and scientific and statistical predictions are made based on the evidence from other crime scenes.
What type of data is the bottom-up approach based on?
Bottom-down approach is based on quantitative data.
-More objective and reliable than top-down approach - more scientific.
-Helps to show how and why variations in criminal behaviour occur - not interested in subjective constructions about what happened.
What are 2 forms of the bottom-up approach?
1) Investigative psychology
2) Geographical profiling
-No pre-established typology - instead develops a data-driven profile.
*Both likely to come up in exam
What is geographical profiling? What does it involve? What principle is it based on?
A form of bottom-up profiling that uses information about the location and timing of linked crime scenes to make inferences about the likely home, work or operational base of an offender - (crime mapping - linked crime scenes plotted to create a ‘jeopardy surface’).
-Concerned with the where, rather than the who or the why.
-Based on the principle of spatial consistency - that people commit crimes within a limited geographical area. Offenders more likely to commit crimes in areas that they know.
-People reveal themselves through their chosen location as much as they do through their behaviour.
-Implies that an offender’s operational base and possible future offences can be revealed by the geographical location of their previous crimes.
-A hypotheses can be created on how the offender is thinking as well as their modus operandi.
-Can be used in conjunction with psychological theories (i.e those used in investigative psychology).
What theory did Canter and Larkin (1993) propose? What is the difference between the marauder and the commuter offender?
Canter and Larkin (1993) - Circle theory of environmental range.
-Proposes that offenders commit crimes within an imagined circle.
-This circle forms the spatial pattern of offending.
-The offender’s base is the middle of the circle / spatial pattern.
-The spatial decision-making (where) of an offender can offer insight into the nature of the offence (modus operandi) - planned or opportunistic, as well as revealing other important factors such as modes of transport, age, employment status etc…
2 types - based on the distribution of offences (not pre-established):
1) Marauder - an offender whose home is within the area the crimes were committed (most common - 91%).
-Their base and anchor point (middle of the circle) is home.
-Bounded by psychological barriers.
-Easier to geographically profile.
2) Commuter - an offender who travels to another area to commit a crime.
-Their base (middle of the circle) is away from home which may even be outside the circle.
-They lack an anchor point and commit crime over large areas - may not even operate within a circle.
-No psychological boundaries.
-Involves hunting strategies.
-Harder to geographically profile.
What computerised system did David Canter develop for geographical profiling?
Canter (2003) - ‘Dragnet’ developed.
-Used information about the location of offences to predict where an offender is likely to live.
-Remember, the bottom-up approach is data-driven.
What is investigative psychology? What does it involve? What principle is it based on?
A form of bottom-up profiling that matches details from the crime scene with statistical analysis of a typical offender’s patterns of behaviour based on established psychological theories - the aim is to establish patterns of behaviour that are likely to occur or co-exist across crime scenes and to use this to link a series of offences to one likely offender (‘case linkage’).
-Grew out of geographical profiling.
-Based on the principle of interpersonal coherence - that the way an offender behaves while committing a crime, including the way they ‘interact with the victim, may reflect the way they behave and interact in their everyday life.
-The concept of ‘forensic awareness’ must also be taken into account - if the person has been subject to police interrogation before, their behaviour may denote how mindful they are of covering their tracks.
-A statistical database is established which then acts as a base for comparison.
What series of London rapes and murders was David Canter asked to help investigate? How did Canter involve both forms of the bottom-up approach?
‘The Railway Rapist’ John Duffy.
-John Duffy carried out 24 sexual attacks and 3 murders of women near railway stations in North London in the 1980’s.
-Using crime scene evidence and information, Canter applied statistically analysed typical behaviour (based on psychological theories) to suggest where the offender was living, his type of job, his social life and his history of offending.
-Canter also analysed geographical information from the crime scenes of the previous attacks.
-Canter drew up a profile of the offender which proved surprisingly accurate as police began covertly observing Duffy - he lived near the area, was separated from his wife, had attacked his wife.
-This led (indirectly) to his eventual arrest and conviction - Canter’s contribution simply narrowed down the list of suspects to save the police time (so useful, but didn’t actually identify the offender directly).
Used geographical profiling and investigative psychology.
What are the strengths and limitations of the bottom-up approach?
Strengths:
-Lundrigan and Canter (2001) - using smallest space analysis - a technique that identifies correlations across different samples of behaviour - it was revealed that there was spatial consistency in the behaviour of the killers involved in 120 murder cases. There was a ‘centre of gravity’ as the body sites created a circular effect around the operational base - more noticeable for marauders.
-Canter and Heritage (1990) - smallest sample analysis used to identify several common behaviours common in different samples of behaviour across 66 sexual assault cases (e.g use of impersonal language and lack of reaction to the victim) and each individual displayed a characteristic patterns of such behaviour - this supports interpersonal coherence as the basis for investigative psychology. Also helps establish case linkage.
-Rossmo said that the bottom-up approach helps to target individuals that otherwise might not have been identified.
-More holistic than top-down approach - draws on a variety of psychological methods
-Increased validity.
-Statistical basis makes it more objective and reliable than the top-down approach.
-Can be applied to a wide range of offences.
-Copson (1995) - surveyed 48 police departments - found that the advice of the profiler was judged to be ‘useful’ in 83% of cases - suggests it’s a valid investigative tool.
Limitations:
-Geographical profiling and investigative psychology may not be sufficient on their own - they are reliant on access to and quality of data. This means they are not always accurate and can’t be used as standalone tools that the police can use.
-Ainsworth (2001) - the time of the offence and the age/experience of the offender are equally important in successfully capturing an offender - geographical information alone may not be enough.
-Case linkage is dependent on already solved historical crimes in a database - this means that investigative psychology is not really useful for crimes that have few links.
-‘Marauders’ and ‘commuters’ too generic - Canter and Larkin (1993) found that 91% were marauders.
-Copson (1995) - only 3% said it actually helped to catch the correct offender.
-An imagined circle is problematic - so still not completely scientific.
-Useful in narrowing down, but not for actually identifying.
What debate do biological explanations for offending behaviour fall into?
Nature-nurture - the question of whether criminals are born or made is certainly under this debate.
-Biological explanations for offending can be both nature and nurture.
-Nature = criminal behaviour may be inherited.
-Nurture = criminal behaviour may be due to acquired abnormalities in brain structure.
What are the 2 types of biological explanations for offending behaviour?
1) An historical approach - Atavism / Atavistic form.
2) Genetic and neural explanations - a more modern approach. (*due a question).
What book did Cesare Lombroso write in 1876? What theory did Lombroso suggest in this book? What did he base his theory on?
1876 - Cesare Lombroso, an Italian physician, eugenicist and phrenologist, wrote ‘L’Uomo Delinquente’ (Criminal Man).
-In this book, Lombroso suggested his theory of the atavistic form.
-His theory was based on his own study on criminals.
-Lombroso’s work was also influenced by and seen as supporting the eugenics philosophy and its practices.
-Eugenics, which was heavily influenced by Charles Darwin’s biological concept of ‘survival of the fittest’, was developed by Sir Francis Galton (Darwin’s cousin) in the 1880’s as a method of improving the human race by increasing the occurrence of heritable characteristics regarded as desirable through selective breeding.
-Based on the concept of social Darwinism.
What is Lombroso’s theory of the atavistic form? How does it explain offending behaviour?
A biological approach to offending that attributes offending behaviour to the fact that offenders/criminals are ‘genetic throwbacks’ - a reversion to a primitive subspecies ill-suited to the rules and expectations of modern society.
-‘Atavistic’ = reversion to ancestral.
-Offending behaviour an innate natural tendency, rooted in the genes of those who engage in it.
-Suggests that some people are ‘born criminal’ - i.e innately and inherently prone to criminality - they are not responsible for their actions and should not be blamed.
-Thus, criminals are biologically different from non-criminals in that they lack evolutionary development.
-Criminals find it impossible to adjust to the demands of society and will inevitably turn to crime.
-Such individuals are distinguishable by particular facial and cranial characteristics indicative of apes, lower primates, and early humans.
How did Lombroso (1876) conduct the study that formed the basis of his theory? What were the findings? What did he conclude?
Lombroso (1876) - aimed to identify distinguishing facial and cranial features among Italian male convicts (in prison).
-Examined and measured the features of 4000 criminals, as well as the skulls of 400 dead criminals.
-No control group.
Findings:
-40% of those examined had atavistic features, which indicated that such people were more primitive in an evolutionary sense.
-This relatively low correlation of 40% was used to justify an entire theory.
Conclusion:
-Lombroso concluded that there was an ‘atavistic form’ and that these features were key indicators, as well as the cause, of criminality.
-He also said that certain atavistic features were associated with certain crimes.
What are the general atavistic characteristics / ‘markers’ according to Lombroso? What other non-facial/cranial atavistic features did he suggest?
Atavistic characteristics (SHREK):
-Sloping, narrow brow (protruding forehead)
-High cheekbones and facial asymmetry
-(Really) large, prominent Jaw
-Ears are long
-K(c)urly hair
Other non-facial/cranial ‘markers’ include:
-Dark skin
-Extra toes, nipples or fingers
-Insensitivity to pain
-Use of slang
-Tattoos
-Unemployment
How did Lombroso categorise particular types of offenders in terms of facial and physical characteristics?
-Murderers - bloodshot eyes, curly hair and long ears.
-Sexual deviants - glinting eyes, swollen fleshy lips and projecting ears.
-Fraudsters - thin and ‘reedy’.
Which 2 studies support Lombroso’s theory?
1) Kurtzberg (1968) - found that the recidivism (reoffending) rate of prisoners decreased following facial surgery - had surgery (42%), no surgery (70%) - suggest their behaviour improved because of the facial surgery.
-Possibly as a result of the prisoners being treated differently due to their new appearance.
-However, you would expect a recidivism rate of close to 0% to be objectively sure.
2) Kretschmer (1921) - found 4 somatotypes, each associated with certain crimes:
-Tall and thin - petty thieves.
-Tall and muscular - violent crime.
-Short and fat - crimes of deception and sometimes violence.
-More than one type - crimes against morality (e.g prostitution).
What are the advantages and disadvantages of Lombroso’s theory of the atavistic form?
Advantages:
-Hugely influential - the first to establish a more scientific basis for the study of crime - ‘the father of modern criminology’ (he himself coined the term ‘criminology’).
-Revolutionary - Lombroso’s ideas challenged the Western notions of individual responsibility and that criminals were wicked or weak-minded. Instead, he offered a new perspective: that offending behaviour was innate and down to genetics - therefore an offender was not to blame for his actions.
-Led to the study of further biological explanations later down the line - e.g genetic and neural.
Disadvantages:
-Unscientific - Lombroso’s theory of the atavistic form is speculative and naive by today’s standards. Correlation does not mean causation - there was a correlation of 40% in Lombroso’s study (not 100%).
-As a fundamentally eugenicist theory, Lombroso’s research is pseudoscientific (pretend science) - the implication of a trait as desirable or undesirable is a subjective cultural choice, not a matter that can be determined through objective scientific inquiry.
-Racist - DeLisi (2012) branded Lombroso’s theory as racist. E.g the atavistic features of curly hair and dark skin most likely to be found among people of African descent, therefore justifying and reinforcing pre-existing prejudices and stereotypes towards black people (in line with 19th century eugenic attitudes).
-Exacerbated the criminal stereotype - social or environmental factors as to why people might commit crime ignored.
-Gender bias (beta bias) - Lombroso only used men in his 1876 study. Yet, his theory of the atavistic form attempts to explain behaviour for both men and women. This weakens the validity of his explanation. Female offenders have different features: shorter, more wrinkled, darker hair, smaller skulls.
-Deterministic - implies that people with atavistic feature have absolutely no free will to stop themselves from offending.
-Also ignores the fact that facial and cranial characteristics are not always genetically determined. Poor diet or an injury are not accounted for in Lombroso’s theory.
-Contradictory evidence - Goring (1913) - tested Lombroso’s atavistic form by comparing 3000 criminals to 3000 non-criminals. Found no difference between the groups in terms of facial characteristics - therefore, criminals are unlikely to be a primitive subspecies.
-Lack of control - unlike Goring, Lombroso did not compare his offender sample with a non-offender control group. This is a confounding variable because it ignores the links between crime and certain social conditions such as poverty and lack of education. These links may explain why offenders were more likely to be, for example, unemployed or have certain physical characteristics.
What do genetic explanations for offending behaviour propose?
Propose that one or more genes predispose individuals to criminal behaviour - suggests that offending behaviour is to some extent inherited.
What is the MAOA gene? What does the MAOA gene provide instructions for? What does the MAOA enzyme do?
MAOA gene - the ‘warrior gene’.
-The MAOA gene provides instructions for the making an enzyme called monoamine oxidase A (alpha) - (the MAO-A enzyme).
-The MAO-A enzyme regulates serotonin (a monoamine) by breaking it down in the synapse after synaptic transmission.
Why is the MAOA gene associated with aggressive behaviour? Which variant causes this? How might this lead to offending?
MAOA is a candidate gene (creates vulnerability) for aggressive behaviour.
-Some people have a low expression variant of the MAOA gene known as MAOA-L.
-The MAOA-L gene produces less of the MAO-A enzymes.
-Therefore less serotonin in the brain is broken down, causing levels to be high - so can’t be *regulated.
-Serotonin is thought to play an important role in impulsive aggression and loss of control, leading to offending.
*The main thing with levels of neurotransmitters is that they need to be stable (regulated) for our mood to be stable - and our genes are helping the neurotransmitters to produce expected behaviour. So don’t worry about genetic explanation saying high serotonin, and neural explanation saying low serotonin.
How does Han Brunner et Al (1993) support the role of the MAOA gene variant in aggressive behaviour? What is ‘Brunner syndrome’?
Han Brunner et Al (1993) - studied 28 men from a large Dutch family who were repeatedly involved in impulsively aggressive violent criminal behaviour.
-Found that these men had the MAOA-L gene variant, and had abnormally low levels of the enzyme MAO-A enzyme in their brains.
-Carrying the MAOA-L gene variant is sometimes referred to as ‘Brunner syndrome’ - characterised by impulsive aggressiveness and MAO-A enzyme deficiency.
Why is Brunner syndrome almost exclusive to men? What does this suggest about men?
The MAOA gene, and its variants (including MAOA-L) is located on the X chromosome.
-Because males only have one X chromosome (XY), the gene cannot be diluted by another X chromosome, as is the case in females (XX).
-This means that Brunner syndrome (i.e MAOA-L variant) is more likely to be inherited by men.
-Suggests that men are more genetically predisposed to impulsive aggression - could potentially explain why most violent offenders are men.
How does Case et Al (1995) support the role of the MAOA gene variant in aggressive behaviour?
Case et Al (1995) - studied genetically engineered mice to have low MAO-A levels.
-Found that the mice had abnormal serotonin levels and behaviour.
-They demonstrated increased levels of aggression and were aggressive during mating.
-But, the findings can’t be generalised to humans as mice don’t have conscious thoughts and behave instinctively - so this study should only used as an additional layer of support.
What other gene has been linked to violent crime? What did Tiihonen et Al (2015) find about the role of MAOA and CDH13 in severe violent crime in Finland?
MAOA not the only candidate gene linked to offending behaviour and violent crime.
-The Cadherin-13 (CDH13) gene and CDH13 deficiency has also been linked to violent crime, as well as substance abuse and ADHD.
-Tiihonen et Al (2015) - studied 900 offenders and found evidence of low MAO-A and CDH13 activity. Estimated that 5-10% of all severe violent crime in Finland is attributable to either the MAOA or CDH13 genotypes.
Where does most of the evidence for the genetic explanation of offending behaviour come from?
Twin studies - illustrate the importance of genes.
-Identical (Mz) and non-identical twins (Dz) are compared.
What did Christiansen (1977) investigate? What were the findings? What do they suggest?
Christiansen (1977) - studied over 3500 pairs of twins in Denmark and established concordance rates for offending behaviour.
Findings:
-Male twins - found concordance rates of 35% (Mz) and 13% (Dz).
-Female twins - found concordance rates of 21% (Mz) and 8% (Dz).
Conclusion:
-In both males and females, concordance rates for identical (Mz) twins is more than double that of non-identical (Dz) twins. This suggests that genes do play a role in offending behaviour - an element of heritability (albeit low) to criminal behaviour, meaning that predisposing traits can be inherited.
-However, the concordance rates were not 100% for Mz twins, which suggests that there must be other factors influencing offending behaviour.
What did Grove (1990) investigate? How were the twins assessed? What did they find? What does this suggest?
Grove (1990) - investigated the role of genes in offending behaviour, but using twins reared apart - all about minimising the effects of nurture (so we can see the real genetic contribution).
-32 Mz twin pairs, who grew up in different environments, were assessed through tests and interviews in terms of alcohol/drug problems and symptoms related to antisocial behaviour in childhood and adulthood.
Findings:
-Found that there was a (statistically significant) positive correlation between genetic influences and symptoms of antisocial behaviour - 0.28 for childhood antisocial behaviour, and 0.41 for adulthood antisocial behaviour.
Conclusion:
-Suggests that there is a genetic contribution to offending behaviour (or in this case antisocial behaviour).
-However, the correlations are relatively low / moderate, which indicates a contribution of environmental factors as well.
What is the diathesis-stress model? How does it relate to offending behaviour? How does this link to epigenetics?
The diathesis-stress model is a model used in genetics for conditions (or behaviours) that may require environmental stressors to trigger them.
1) Genetic Predisposition - the vulnerability to committing crime from candidate genes (e.g MAOA-L, CDH13).
2) Environmental Stressor - an aspect of the environment which triggers the person to actually offend and become a criminal. E.g the MAOA gene had to be activated - usually by exposure to extreme violence.
-Crime is not exclusively genetic - we know because concordance rates aren’t 100% for Mz twins.
-However, there may be biological tendencies towards offending behaviour, which come about through this combination of genetic predisposition and an environmental trigger - e.g criminal role models, a dysfunctional environment, exposure to violence.
-It’s about the interplay between genes and the environment. Epigenetics proposes that genes are switched on or off, altering genetic expression, in relation to environmental factors - aspects of lifestyle or events we encounter leave ‘marks’ on our DNA.
What do neural explanations for offending behaviour propose?
Propose that there may be neural differences in the brains of criminals compared to non-offenders - i.e dysfunctions of the brain and nervous system.
-Considers how structures in the brain may be different in criminals, as well as differences in neurotransmitter levels.
Which neurotransmitters are associated with offending behaviour?
-Serotonin - low levels may predispose individuals to greater impulsivity and a lack of self-control due to a lack of inhibition of impulsive urges by the prefrontal cortex. Dopamine hyperactivity may enhance this effect.
-Noradrenaline (Norepinephrine as a neurotransmitter) - high levels of noradrenaline have been linked to aggression and violence (because part of fight or flight).
What is APD? How does it link to the neural explanation?
Antisocial personality disorder (APD) - formerly referred to as psychopathy.
-A disorder associated with reduced emotional responses and a lack of empathy.
-It is a condition that characterises many convicted offenders - common among criminals.
-Much of the research focuses on individuals diagnosed with APD - e.g Adrian Raine’s PET scans.
What has Adrian Raine said about APD brains? What is the role of the prefrontal cortex and limbic system (amygdala) in offending behaviour? What 3 Adrian Raine studies support this?
Adrian Raine has conducted many APD brain-imaging studies using PET scans (and MRI).
-He has found that individuals with APD have reduced volume and activity in the prefrontal cortex - this caused the impulsiveness and lack of control associated with offending behaviour.
Prefrontal cortex:
-The prefrontal cortex is the part of the brain involved in regulating emotional behaviour, planning, decision-making, and controlling moral behaviour in general (choosing between right and wrong).
-Low activity and volume in the prefrontal cortex associated with impulsiveness and loss of control - can’t rationalise behaviour, which leads to poor decisions and possibly criminal behaviour.
Research (prefrontal cortex):
-Raine (2004) - 71 brain-imaging studies showed that murderers, psychopaths and violent individuals have reduced functioning in the prefrontal cortex.
-Raine et Al (2000) - MRI scans found an 11% reduction in the volume of grey matter in the prefrontal cortex of 21 people with APD compared to a control group of 21 people without APD.
-Overall summary of prefrontal cortex - reduced functioning/activity and volume of prefrontal cortex is common in violent offenders, suggesting less control over impulsive behaviour.
Limbic system (amygdala):
-Limbic system is the group of subcortical structures in the brain (including the amygdala, thalamus, hypothalamus, hippocampus etc…) thought to be closely involved in regulating emotional behaviour - including aggression.
-The amygdala is part of the limbic system and is the brain’s emotional centre.
-Reduced volume in the limbic system, particularly in the amygdala, associated with no remorse, guilt or empathy.
Research (limbic system):
-Raine et Al (1997) - studied the brain activity of murderers (found not guilty by reason of insanity - NGRI) and 41 non-murderers using PET scans. Found abnormal asymmetries and reduced volume in the limbic system of murderers, especially in the amygdala.
How late does the prefrontal cortex develop? What might this tell us?
The prefrontal cortex develops relatively late, sometimes not fully developed until early 20’s and later in males.
-This may explain the peak in antisocial behaviour in male teenagers.
What are the advantages and disadvantages of genetic explanations for offending behaviour?
Advantages:
-Research support - from twin studies.
-Diathesis-stress model takes into account both biology and environment.
Disadvantages:
-Issues with twin studies - works on the assumption of equal environments for twins growing up together. Even if you get around this by using twins reared apart, the environment is still a factor.
-Biologically reductionist - there are other risk factors associated with criminality.
-Deterministic - suggest the genes a person is born with determine their later behaviour - implies there is no free will.
What are the advantages and disadvantages of neural explanations for offending behaviour?
Advantages:
-Research support - Adrian Raine.
-PET scans are an objective and scientific technique - adds value on top of social predictors in terms of whether an individual is likely to commit a violent crime or not - leading to possible early intervention.
-Harmon (2012) - 60% of people in US prisons have had a brain injury.
Disadvantages:
-Biologically reductionist.
-The link between neural differences and APD may be complex. Other factors could be involved in causing APD - e.g childhood neglect, trauma and exposure to other risk factors early on - so not as simple as saying that APD is caused simply by neural differences.
-The environment may even impact physical structures in the brain.
-Neuro-ethical dilemma - to what extent do we hold people responsible if they have early risk factors predisposing them to violent crime.
What are the 4 types of psychological explanations for offending behaviour?
1) Eysenck’s theory - (*likely to come up in exam)
2) Cognitive explanations
3) Differential association theory
4) Psychodynamic explanations
Who was Hans Eysenck? What theory is he best known for?
Hans Eysenck, a German-born British psychologist, was an important figure in personality and intelligence research in the mid-20th century.
-The theory of the criminal personality.
Why is Eysencks’ theory a ‘halfway house’ in terms of the type of explanation it can be classified as?
‘Halfway house’ - Eysenck’s theory of the criminal personality is a psychological explanation as he says personality is shaped by interaction with the environment through the role of socialisation, but his arguments (about the nature of personality types) have a biological basis.
-Interactionist approach (nature-nurture) - issues and debates.
-Criminality a combined outcome of innate personality (i.e High PEN) and socialisation (where personality is shaped) - this is what makes Eysenck’s theory a psychological explanation.
What did Eysenck’s theory of personality (1947) initially focus on? What did it say about the nature of personality? How many dimensions did this theory say there were to personality?
Eysenck’s theory of personality (1947) - focused on personality in general - not yet applied to criminal behaviour and the idea of a criminal personality.
Theory:
-Eysenck said that personality is innate and therefore has a biological basis.
-He said we inherit a type of nervous system that predisposes us to certain personality traits that vary along 2 dimensions - extraversion-introversion (E) and neuroticism-stability (N).
-The extent to which you have these traits across the 2 dimensions determines your personality.
How and when did Eysenck apply his theory to criminal behaviour? What personality dimension did he add? What characterises someone with a criminal personality?
Eysenck (1964) - applied his general theory on personality to criminal behaviour, proposing a personality type called the criminal personality.
Theory of the criminal personality:
-Third dimension of psychoticism-sociability (P), added to extraversion-introversion (E) and neuroticism-stability (N).
-Eysenck said that personality varies along these three dimensions, but that the criminal personality scores highly on measures of extraversion, neuroticism and psychoticism - (‘High PEN’).
-This personality type is no different to others in that it is innate. Therefore, if you inherit the criminal personality, Eysenck says you are predisposed to offending and becoming a criminal.
-By contrast, most people would gain a low score on psychoticism and fall in the middle of the E and N spectrum.
What is the ‘recipe’ for the criminal personality?
‘High PEN’ - the criminal personality is someone who is extraverted, neurotic and psychotic.
What is extraversion and introversion? What are the characteristics of extraverts and introverts? What is the biological basis for extraversion and introversion? How might the biology behind extraversion lead to the offending behaviour?
Extraversion (correct spelling in psychology - not extroversion):
-The personality trait referring to a state of being where someone draws energy from being with other people.
-Characteristics - sociable/outgoing, talkative, impulsive, expressive (tend to flip very easily) and happy to take risks (criminality is inherently risky as your freedom is on the line).
Introversion:
-The personality trait referring to the state of being where someone draws energy from being alone.
-Characteristics - happy on their own, reflective, cautious and self-aware.
Biological basis for extraversion (and link to offending behaviour):
-Extraversion is due to a chronically under-aroused nervous system (in terms of cortical activity - lower).
-Because the nervous system is less responsive, this leads to thrill-seeking behaviour as the person seeks out external stimulation - hence more likely to engage in risky behaviour (possibly criminal activity) and more impulsive.
-Extraverts also do not condition easily and do not learn from their mistakes - hence more likely to reoffend.
Biological basis for introversion:
-Introverts have higher levels of cortical activity than extraverts - meaning their nervous system is highly responsive and so they require less external stimulation.
-This explains why introverts are less outgoing and take less risks.
