Forensic Psychology Flashcards
What is offender profiling?
Used to identify suspects
Determine most likely characteristics
Outline Top Down approach
FBI interviewed 36 sexually motivated killers to gain insight on patterns in behaviour and thinking
- based on intuition and deductive reasoning (not empirical data)
- appies theories and concepts to information at the crime scene
follows stages developed by FBI (see later)
data from interviws and crime scenes helped identify 2 catagories of offenders
- organised and disorganised
found these characteristics often related to their personal life and the crime scene
- helps identify characteristics
Characteristics of an organised offender
Personal life:
- intelligent - employed
- socially competent - have friends and relationships
Crime scene:
- no forensic evidence
- planned
- shows control
Characteristics of a disorganised offender
Personal life:
- unemployed/ low skilled
- behaves impulsively
- socially incompetent - few friends/ loner
Crime scene:
- forensic evidence
- unplanned
- shows no control
FBI stages in developing a profile
- Assimilating data - collecting all information from scene and victim
- Crime scene classification - organised or disorganised
- Crime scene reconstruction - recreate behaviour and actions of offender and victim
- Generate a profile - make judgement of possible physical and lifestyle characteristics
Strengths of Top Down
+ Copson, 90% senior officers would use it again
real world application
+ makes use of expertise
Based on intuition so utilises the experience of profilers to make judgments that a model couldn’t make - may be more accurate
Weaknesses of Top Down
- small sample size, can’t be generalised to all crimes, 36
- based on self report interviews, subjective and unreliable (likely to lie)
- temporal validity - interviews in 70s
- can’t be categorised into one of 2 categories, may be mixed - less valid/useful
Canter (2004) - Allison, 50% officers said profile was accurate when it was fake (distinctly different to actual offender)
Outline Bottom Up approach
developed by David Canter
- based on statistics and past cases rather then deduction
- uses data at scene as source of information to develop a theory (of offender)
investigative psychology - applying psychological research to investigations
- Interpersonal coherence - offender behaves consistently so crime scene reflects everyday behaviours
- forensic awareness - how well crimes were covered could indicate past convictions
geographical profiling - uses location as clues to offenders job, life etc
- circle theory - offenders commit crimes in certain radius of where they live (marauder) or where they know well (commuter)
Strengths of Bottom Up
+ emphasis on data, more scientific, uses more objective techniques
Less intuition
therefore more reliable
+ Canter and Larkin, support for circle theory in 45 sexual assults
+ Copson - 75% police officers said useful
Weaknesses of Bottom Up
- circle theory oversimplified
more useful for some crimes
- 85% murder
- 50% theft
effectiveness
- Copson - only 3% officers found it helped to actually identify offender
- Petherick - claimed geographical profiling encourages officers to look in wrong direction, may not always be certain radius
Less useful
issues with offender profiling
Holmes
in 192 cases using offender profiling
only 88 arrests made
profiling helped with 17% of these
only useful for limited range of crimes
- not useful for material gain eg theft
Biological approaches to offending behaviour
Lombroso - atavistic form
Genetic
Neural
Outline Lombroso
Linked physical characteristics to crime (those with features had innate criminal tendencies)
Criminals more likely to have atavistic features (primitive)
- strong jaw
- heavy brow
- large ears
Believed criminality came from primitive instincts that had survived evolution - ‘genetic throwback’
Strengths of Lombroso
+ highlighted role of biology
+ suggests interactions between biology and environment, highly influential
+ scientific for the time - studied criminals systematically with over 50,000
Weaknesses of Lombroso
- didn’t use non criminal control, features not unique to criminals
- ethnocentrism - problematic views on different races, believed they were born criminals (evolutionary throwback)
- unethical - prejudice towards those with characteristics
- reductionist - explains complex idea through physical characteristics, ignores environment
- biological determinism, innate and inherited, can’t be blamed
Genetic explanations for offending behaviour
Gene predispose individuals to criminal behaviour
- evidence from twin and adoption studies
Candidate genes found
- mutation of MAOA - causes abnormal serotonin levels (warrior gene)
- Brunner et al, violent male family members, inherited - all had MAOA
Evidence for genetic explanations
+ Raine, concordance rates in delinquent twins
- 52% MZ
- 21% DZ
+ Mednick, 14,000 adoptees
15% sons adopted by criminal families
20% biologically related to criminals became criminals
Shows genes more influential than environment
Neural explanations for criminal behaviour
Abnormal transmission of neurotransmitters
- serotonin - inhibitory neurotransmitter
- low levels linked to impulsive offending behaviour
Differences in brain functioning
- less activity in prefrontal cortex - linked with regulating emotion and moral behaviour
- leads to impulsiveness
Evidence for neural explanations
+ Raine, PET scans
Murderers shows reduced activity in prefrontal cortex
Associated with regulating emotion
Shows dysfunctional brain processing in criminals
+ Seo et al, low levels of serotonin
Predispose people to aggression and crime
Weaknesses of genetic explanation
- no study found 100% concordance rates, must involve other factors
- biological determinism
- reductionist
- Caspi - those with MAOA gene only became violent if mistreated in childhood
Interactionist approach
Weaknesses of neural explanation
- biological determinism
- reductionist
- correlation doesn’t mean causation