forensic psych Flashcards
what is the american profilling system
top-down approach
what does the top-down approach mean
means the profillers start with pre-established typology and work down in order to assign offenders to categorise based on evidence from the crime scene
who develpoed the top-down approach and when
the FBI’s behavioural science unit in the 1970’s
how was the top down approach developed
in depth iterviews with 36 sexually motivated serial killers
what are the two categoires in top-down
- organised
- disorganised
describe the organised catagory
general approach, weapons, evidence, victim, offender
general approach - planned and controlled
weapons - brought to scene and taken away
evidence - destroyed or removed
victim - attempts to control (eg restraints), may be carefully chosen (fits a ‘type’)
offender - unknown to victim, socially/sexually contempt, living with partner, above average intelligence, angry/depressed
describe the disorganised catagory
general approach, weapons, evidence, victim, offender
general approach - unplanned and chaotic
weapons - improvised, left at scene
evidence - left at scene, no attempt to hide/destroy evidence
victim - little attempt to control, randomly chosen (wrong place, wrong time)
offender - possibly known to victim, socially/sexually inept, living alone, below average intelligence, anxious/psychotic
what is the process of constructing an FBI profile
- data assimilation (looks at evidence)
- crime scene classified (into 1 of 2 types)
- crime reconstruction (of sequence of events, behaviour of offender+victim)
- profile generation, related to likely offender (eg demographic background, physical characteristic, behaviours)
opposing evidnece to top down
Pinizzotto and Finkel (1990)
* compared five groups on their ability to write profiles of a solved murder case
* groups were: expert profilers, detectives with profiling expereince, detectives without profilling experince, clinical psychologists and undergrads
* detectives without profilling experince were significantly more accuarate in predicting characteristics of the murderer than any group
what does Pinizzotto and Finkel’s evidence suggest about top down approach
- not effective
- waste of time and money training people in top down
limitation of top down
development
- based on static and outdated models of personality
- assumes offenders have behaviours+motivations that remain consistent consistent across situations – however critics have argued that personality is more dynamic and affected by external factors
ANOTHER LIMITATION - developed by interview of 36 american killers
limitation of top down
applicability
- only applied to certain crimes eg serial murder and rape
- especially if they involve practices such as sadistic torture, dissection of the body and acting out fantasies - these offences are rare
- more common offences such as burgulary dont lend themselves to top-down because the crime scenes reveal very little about the offender
limitation of top down
simplistic
- classification of organised and disorganised is too simplistic
- many characteristocs of the types aren’t mutally exculsive and instead mnay crime scenes show a combination of characteristics
Holmes (1998) suggests there are 4 types of serial killer: visionary, mission, hedonistic and power/control - limitation because questions validity of top-down approach and the use of two categories for classification
what is britains profiling systen
bottom=up approach
what techniques are used in bottom-up
- investigative psych
- geographic profiling
what is investigative psych
investigative psychology is the use of scientific psychology and psychological theory to solve crimes and identify criminals.
two aspecvts in investigative psych
1.** interpersonal coherence**- his means that the way a criminal behaves when they are committing a crime will be consistent with how they behave in everyday life.
2. statistical analysis- identify common themes and patterns of behaviour across several crime scenes, Statistical data can also be used to provide information about the offender’s location through geographical profiling.
what is geographical profiling
use of statistical analysis to make inferences about the offender’s geographical location.
what is the circle hypothesis in regards to geographical profilling
says that serial offenders carry out their crimes within a geographical circle. The circle hypothesis also predicts that the offender’s home will be within this circle.
what are the two geographical models for offending locations
- the marauder
- the commuter
where does the marauder commit crime
commits crimes within a criminal range from their own home
where does the commuter commit crime
Travels away from their own home to an area and then commits crimes within a criminal range of that area
strengths of bottom up approach
- supporting evidence
- wider applications
- more scientific
supporting evidence for bottom up
investigative psych
David Canter used his bottom-up profiling methods to develop a profile of the ‘Railway Rapist’ – responsible for several rapes and murders of women near railway stations in south-east England in the 1980s. Canter developed the profile of a man in his mid-late 20s, with a criminal record, working in a semi-skilled job, who had a poor relationship with women, knowledge of the railways, and lived near the crime scenes. This profile turned out to closely match the details of the offender, John Duffy, who was found guilty of these crimes.
supporting evidence for bottom up
geographic profiling
In addition to Canter and Larkin (1993) above, several studies support the validity of geographical profiling. For example, Canter and Lundrigan (2001) plotted the locations where 120 serial killers disposed of bodies and analysed this data using a statistical technique called smallest space analysis. The researchers found the killers’ homes tended to be in the centre of the plotted area where they disposed of bodies, which supports the validity of geographical profiling.
wider application of bottom up approahc
Whereas the top-down approach only really works for crimes with a particular modus operandi, such as rape and murder, the bottom-up approach can be applied to a much wider range of crimes. For example, most burglaries are similar in method and so a top-down approach won’t reveal much about the offender’s profile. However,* geographical profiling only requires the locations of the crimes, and so this bottom-up approach can be applied to basically every type of crime.*
how is bottom up apparoch more scientific
relies on objective and measurable data (e.g. plotting geographic locations of crimes), uses mathematical tools (e.g. statistical analysis), and is often based on psychological theory (e.g. interpersonal coherence). Because of this, Canter argues the bottom-up approach is more scientific than the top-down approach, which relies more on intuition and gut-feeling.
weakness of bottom up approach
Conflicting evidence: Copson (1995) surveyed 184 UK police officers (UK = bottom-up approach) on the use of offender profiles created by trained profilers. Although 83% of the police surveyed said the profiles were ‘useful’, just 3% of profiles created by trained profilers resulted in identification of the offender. This suggests bottom-up profiles are not particularly useful in practice.
what are the 3 biological explanations for crim. behaviour
- Atavistic form
- Genetics
- Neural factors
who created atavistic form
lombroso
what is atavistic form
proposed that criminals are biologically different from modern humans. He argued that criminals have more in common with our evolutionary ancestors than normal humans do.
The idea is that criminality represents the behaviours of earlier, more savage, pre-human species – like Neanderthals or homo habilis.
examples of facial features of criminal accoridng to lombroso
- heavy brow
- strong jaw
- extra fingers/toes
according to lombroso how may diff. criminals look
a murderer and a sex offender
argued that murderers typically have curly hair and bloodshot eyes, whereas sex offenders have swollen and fleshy lips
strength of atavistic form
Historical influence: Even though Lombroso’s atavistic form explanation is widely dismissed by modern-day scientists, it played an important role in advancing criminology and scientific explanations of criminal behaviour. Prior to Lombroso, explanations of criminal behaviour tended to be religious (e.g. bad spirits, Satan, etc.) or moralistic (e.g. weak-mindedness). In appealing to evolutionary reasoning, Lombroso’s approach shifted the discussion towards more scientific explanations. This paved the way for more scientific explanations of criminal behaviour, such as genetic factors.
what are the weaknesses of atavistic form
- methodological concerns
- alternative explanations
- ethical concerns
methodological concerns
weakness of atavistic form
A key methodological flaw in Lombroso’s approach was that he did not use a non-criminal control group to compare his measurements of criminals against. Without comparing the features of criminals against the features of non-criminals, it is impossible to say whether criminals do actually have distinctive features that differentiate them from non-criminals as Lombroso claimed.
alternative explanations
weakness of atavistic form
Even if it were true that criminals do have distinctive facial structures, there might be other causal reasons for this besides having evolutionarily primitive (atavistic) biology. For example, if someone is ‘ugly’, this could cause other people to treat them badly and this bad treatment could cause a person to engage in criminal behaviour. In this case, the link between physical appearance and criminal behaviour would be the result of environmental factors rather than biological factors (i.e. atavistic form).
ethical concerns
weakness of atavistic form
Lombroso’s atatvistic form explanation is socially sensitive because it could lead to stereotyping and discrimination based on the way a person looks.
twin studies to support genetic explanation
2
- Christiansen (1977) analysed the concordance rates for criminal convictions among 3,586 pairs of twins. Among males, concordance rates were 35% for identical twins and 12% for non-identical twins. Among females, the concordance rates were 21% for identical twins and 8% for non-identical twins
- Lange (1931) compared concordance rates for prison sentences among 13 identical twins and 17 non-identical twins. 10 of the 13 pairs of identical twins (77%) had both spent time in prison, whereas only 2 of the 17 non-identical twins (12%) had both spent time in prison.
These studies show the concordance rates for criminal behaviour are higher among identical twins (who share 100% of their genes) than non-identical twins (who only share 50% of their genes). This supports a role for genetics in explaining criminal behaviour.
further study to support genetic explanation
Mednick et al (1984) looked at 14,427 adopted children and compared the likelihood that a child would grow up to engage in criminal activity if their biological parent or adoptive parents were convicted criminals. The results were as follows:
criminal bio+adoptive parents= 24.5%
crim. adoptive+non-crim bio = 14.7%
non-crim adoptive+crim bio = 20%
non-crim bio+adoptive= 13.5%
suggest that having a biological parent who is a criminal is a better predictor of whether the child will go on to be a criminal than if the adoptive parents are crimina
candidate gene linked to criminal behaviour
the MAOA gene is linked with aggressive behaviour (see the aggression page for more details), which is in turn linked with criminal behaviour. For example, Brunner et al (1993) studied a family with a history of aggressive and criminal behaviour, and found that all the male members had the MAOA gene. This is an example of a gene that could (partly) explain criminal behaviour.
The MAOA gene affects how neurotransmitters, such as serotonin, are processed. The fact that this gene is associated with criminality thus also supports a neural explanation of criminal behaviour.
strength of genetic explanation
supporting evidence
weaknesses of genetic explanation
- other factors
- methodological issues
- deterministic
other factors
weakness of genetic explanation
If criminal behaviour was entirely determined by genetics, the concordance rate would be 100% among identical twins. However, both Christiansen (1977) and Lange (1931) found the concordance rates for criminal behaviour among identical twins to be less than 100%, which demonstrates that other factors (e.g. different experiences and psychological factors) are needed for a complete explanation of criminal behaviour.
methodological issues
weakness of genetic explanation
- Twin studies: The usual methodological concerns with twin studies apply to Christiansen (1977) and Lange (1931). For example, it’s possible that identical twins are more likely to be treated similarly than non-identical twins due to their identical appearance. This similarity in environment may be (at least partly) responsible for the higher concordance rates for criminality among identical twins than non-identical twins.
- Adoption studies: There are also methodological issues with adoption studies like Mednick et al (1984), too: Adoptees are often raised by their biological parents for a long time before being adopted, so the correlation between having a biological parent who is a criminal and becoming a criminal could be due (at least in part) to environmental factors rather than genetics.
deterministic
weakness of genetic explanation
Genetic explanations are deterministic because they say that a person’s genes are what cause criminal behaviour, not free will. However, this raises legal and moral issues: It is hard to hold someone morally responsible for criminal actions if they didn’t choose them, and so it may seem unfair to punish them.
what are neural explantions for crime
- brainstructures
- neurotransmitters
brain structures
neural explantions for crime
Raine et al (1997) compared brain scans conducted on 41 convicted murderers and with brain scans conducted on 41 control participants. The researchers observed that the murderers had reduced activity in the prefrontal cortex, the superior parietal gyrus, left angular gyrus, and the corpus callosum compared to the control group.
neurotransmitters
neural explantions for crime
Neurotransmitters, such as serotonin and dopamine, may also explain criminal behaviour. For example,** Brunner et al** (1993) described a link between genes responsible for processing neurotransmitters and violent behaviour. These effects on neurotransmitters may be why these genes increase violent behaviour, suggesting a link between abnormal neurotransmitter activity and criminality.
strengths of neural explanaions of crim behavioue
supporting evidence
weaknesses of neural explanation
- small samples
- ethical issues
- deterministic
small sample sizes
weakness of neural explanation
Studies linking criminal behaviour with neural factors often use small sample sizes. One reason for this is that the population of serious criminals (e.g. murderers) are hard to gain scientific access to. This effect is compounded by the high costs of brain-scanning tools, such as fMRI, which makes it even more difficult to carry out this research on large numbers of people. Because of these small sample sizes, it may be invalid to generalise the findings from these studies to the wider population.
ethical issues
weakness of neural explanation
An implication of Raine’s research is that brain scans in childhood could be used to identify potentially violent criminals of the future. This policy, if enacted, could potentially reduce crime but is* socially sensitive because it could lead to discrimination* against people with these brain structures.
deterministic
weakness of neural explanation
Neural explanations are biologically deterministic because they say that neural factors are what cause criminal behaviour, not free will. However, this raises legal and moral issues: If someone doesn’t choose their criminal actions, it may seem unfair to hold them morally or legally responsible for them.