11. Forensic psychology
Top-down approach:
Offender profiling is used by police to narrow the suspect list. Profilers analyse the crime scene and
evidence to generate hypotheses about probable characteristics of offenders.
Top-down approach: “American approach” – profilers start with established typologies and work down
to assign offenders to categories using the crime scene/witness reports
Originated from FBI in 1970s.
Interviews done with sexually-motivated murderers; concluded that they had certain
characteristics that could be categorised into two types.
1. Organised offender: evidence of planning crime
o Victim is targeted/offender has a certain ‘type’ of victim.
o Evidence of a high level of control; little evidence left at the crime scene.
o Above average IQ/intelligence.
o Skilled occupation.
o Socially competent.
o Often married.
2. Disorganised offender: little evidence of planning; spontaneous
o Evidence of a lack of control (e.g., body left at scene, no attempt to conceal
evidence etc).
o Lower IQ/intelligence.
o Unskilled work/unemployed.
o Sexual/social dysfunction.
o Live alone/close to crime scene.
Profilers collect data from crime scene before deciding on category of offender.
Constructing an FBI profile:
1. Data assimilation: review evidence (crime scene, witness reports, etc.)
2. Crime scene classification: organised/disorganised
3. Crime reconstruction: hypothesis generated about the events of the crime.
4. Profile generation: hypothesis generated related to likely offender and characteristics
EVALUATION:
+ Research support
o Canter (2004): analysis of 100 US murders using smallest space analysis. Found distinct subset of
features that matched ‘organised’ typology.
o Therefore, increases validity of ‘organised’ typology as useful for offender profiling.
HOWEVER: - Typologies are not mutually exclusive
o Godwin (2002): typologies may overlap/there may be combinations of
characteristics for different offenders.
, o Therefore, lowers validity and usefulness of top-down approach for offender
profiling.
- Approach only applies to particular crimes
o E.g., rape, arson etc – crimes that require horrific practices. Not appropriate for burglary; crime
scene reveals little about the offender.
o Therefore, limited application to all offences.
- Flawed evidence (interviews with criminals)
o Canter (2004): poor sample due to all being the same type of offender. No standardised set of
questions used; use of self-report.
o Therefore, hard to compare results; lowers scientific credibility of top-down approach.
Bottom-up approach:
The bottom-up approach generates a picture of offender based on crime scene analysis. It does not begin
with fixed typologies and is ‘data driven’, meaning it uses data about crimes that have been committed to
make predictions about offenders’ characteristics.
Investigative psychology: applies statistical procedures to crime scene analysis
Establishes patterns of behaviour that are likely to occur across crime scenes to generate a
statistical database to be used as a baseline.
Details from crime scenes can be compared to database to reveal offenders’ likely
characteristics/if crimes are linked.
Interpersonal coherence suggests the way an offender behaves at a crime scene may reflect the
way they behave in everyday life.
Time and place of an offence may reveal where the offender lives.
Display of forensic awareness may indicate that the offender has previously been subject to
police investigation and may be known by police.
Geographical profiling: uses information about the location of a crime to make inferences about the
home/base of an offender
Crime mapping is based on spatial consistency, the idea that people commit crime in a limited
geographical space.
Spatial pattern used to create ‘centre of gravity’, likely to include the offender’s base (Canter’s
circle theory).
Used to create hypotheses about hoe the offender thinks and works. Categorised into either
marauder or commuter.
o Marauder = crime committed close to home.
o Commuter = crime committed a distance away from home.
Spatial decision-making can reveal nature of the crime (i.e., planned, or opportunistic), and
information about transport used, employment, age etc.
EVALUATION:
+ Scientific (in comparison to top-down approach)
o Uses statistical data and is evidence-based; does not rely on fixed typologies and inferences.
o Therefore, increased scientific credibility and more reliable than top-down approach for offender
profiling.
- Dependent on the quality of previous data
Top-down approach:
Offender profiling is used by police to narrow the suspect list. Profilers analyse the crime scene and
evidence to generate hypotheses about probable characteristics of offenders.
Top-down approach: “American approach” – profilers start with established typologies and work down
to assign offenders to categories using the crime scene/witness reports
Originated from FBI in 1970s.
Interviews done with sexually-motivated murderers; concluded that they had certain
characteristics that could be categorised into two types.
1. Organised offender: evidence of planning crime
o Victim is targeted/offender has a certain ‘type’ of victim.
o Evidence of a high level of control; little evidence left at the crime scene.
o Above average IQ/intelligence.
o Skilled occupation.
o Socially competent.
o Often married.
2. Disorganised offender: little evidence of planning; spontaneous
o Evidence of a lack of control (e.g., body left at scene, no attempt to conceal
evidence etc).
o Lower IQ/intelligence.
o Unskilled work/unemployed.
o Sexual/social dysfunction.
o Live alone/close to crime scene.
Profilers collect data from crime scene before deciding on category of offender.
Constructing an FBI profile:
1. Data assimilation: review evidence (crime scene, witness reports, etc.)
2. Crime scene classification: organised/disorganised
3. Crime reconstruction: hypothesis generated about the events of the crime.
4. Profile generation: hypothesis generated related to likely offender and characteristics
EVALUATION:
+ Research support
o Canter (2004): analysis of 100 US murders using smallest space analysis. Found distinct subset of
features that matched ‘organised’ typology.
o Therefore, increases validity of ‘organised’ typology as useful for offender profiling.
HOWEVER: - Typologies are not mutually exclusive
o Godwin (2002): typologies may overlap/there may be combinations of
characteristics for different offenders.
, o Therefore, lowers validity and usefulness of top-down approach for offender
profiling.
- Approach only applies to particular crimes
o E.g., rape, arson etc – crimes that require horrific practices. Not appropriate for burglary; crime
scene reveals little about the offender.
o Therefore, limited application to all offences.
- Flawed evidence (interviews with criminals)
o Canter (2004): poor sample due to all being the same type of offender. No standardised set of
questions used; use of self-report.
o Therefore, hard to compare results; lowers scientific credibility of top-down approach.
Bottom-up approach:
The bottom-up approach generates a picture of offender based on crime scene analysis. It does not begin
with fixed typologies and is ‘data driven’, meaning it uses data about crimes that have been committed to
make predictions about offenders’ characteristics.
Investigative psychology: applies statistical procedures to crime scene analysis
Establishes patterns of behaviour that are likely to occur across crime scenes to generate a
statistical database to be used as a baseline.
Details from crime scenes can be compared to database to reveal offenders’ likely
characteristics/if crimes are linked.
Interpersonal coherence suggests the way an offender behaves at a crime scene may reflect the
way they behave in everyday life.
Time and place of an offence may reveal where the offender lives.
Display of forensic awareness may indicate that the offender has previously been subject to
police investigation and may be known by police.
Geographical profiling: uses information about the location of a crime to make inferences about the
home/base of an offender
Crime mapping is based on spatial consistency, the idea that people commit crime in a limited
geographical space.
Spatial pattern used to create ‘centre of gravity’, likely to include the offender’s base (Canter’s
circle theory).
Used to create hypotheses about hoe the offender thinks and works. Categorised into either
marauder or commuter.
o Marauder = crime committed close to home.
o Commuter = crime committed a distance away from home.
Spatial decision-making can reveal nature of the crime (i.e., planned, or opportunistic), and
information about transport used, employment, age etc.
EVALUATION:
+ Scientific (in comparison to top-down approach)
o Uses statistical data and is evidence-based; does not rely on fixed typologies and inferences.
o Therefore, increased scientific credibility and more reliable than top-down approach for offender
profiling.
- Dependent on the quality of previous data
