roles of forensic psych in legal process
roles:
actuarial
clinical
experimental
working with offenders - clinical
risk assessment + management (reoffending, potential criminals)
counselling + treatment
working with law enforcement (police) (investigative)
eyewitness testimony + memory
eye witness interview techniques
Roles as experts in court/ legal process
To improve decision making:
- Clinical (assessment) - risk assessment for reoffending
- Actuarial - likelihood of future events - stats
- Experimental - test plausibility of testimonies practically
Clinical role (assessment)
conducts clinical assessment (questionnaire) to test for:
- ‘fitness to plead’ - mental competence to stand trial - using ECST-R - clinical diagnosis/ assessment in court
- criminal liability: direct intention (mens rea) vs negligence
mens rea
the intention to commit crime - either:
- direct intention (intent to perform crime knowing outcome) or
- negligence/ recklessness (knowledge of risk but still continues - without direct intent to commit crime)
actus reus
voluntary physical action that lead to crime
ECST-R
Evaluation of Competency to Stand Trial - Revised - American semi-structured interview manual used to test for offenders’ ‘adjudicative competency’
e.g, schizophrenia - don’t understand they are being accused
Sally Clark 1996
prosecutor’s fallacy shows statistical prediction cannot prove guilty
sudden infant death syndrome to both her children 1 year apart
Roy Meadow - paediatrician testified it so rare to occur (2 children to die of sids (1/8500 squared = 1/73 million) = she was guilty for murder
- also incorrect stats, 2 children’s death from sids is not independent - genetic/environmental factors
prosecutor’s fallacy
probability of occurrence (both children dying from SIDS) is much rarer than other causes of death BUT not rarer than mother killing both her children.
- issue: probability of the evidence given she is innocent (sids / other causes of death = low, should be sids / murder = P(innocence)=high
- can be applied to eye witness misidentification - prosecutors fallacy present in determining likelihood of innocence given identified by witness vs probability of identification given they are innocent
Experimental role
perform experiments to test plausibility of eye witness testimonies
ex. Glasgow ice cream war murders 1984-2004 - police collusion of identical reports = unlikely considering our memory
eyewitness misidentification stats
Since 1989, 349 wrongful convictions have been overturned through DNA testing, and eyewitness misidentification played a role in over 70% of those cases—far more than any other contributing cause (Innocence Project, 2016)
post crime interference - (Perlini & Silvaggio, 2007)
single blind police lineup reported increased false identification rates from mock eye witnesses with presenting suspect images simultaneously than when shown sequentially. therefore, to reduce bias show images sequentially to reduce police input or do double blind.
extralegal factors - psychology of the court - credibility cues & complexity of argument
high credibility - heuristic causes jargon to introduce bias to rely on credibility of argument/ evidence
post crime interference - (Perlini & Silvaggio, 2007)
(Lowenstein et al., 2010) - uniform on selecting wrong suspect with children
single blind police lineup reported increased false identification rates from mock eye witnesses with presenting suspect images simultaneously than when shown sequentially. therefore, to reduce bias show images sequentially to reduce police input or do double blind.
Johnson & King (2017)
extralegal factors: physical attractiveness in judicial sentencing decisions
probationary sentence
1119 photos of defendants - coders (independant people) rate from 1 -7 defendants’ attractiveness
defendants of higher attractiveness received lighter sentences +1 point = -33% chance to go to prison
working with offenders
- risk assessment + management
- counselling + treatment
HCR-20
Historical, Clinical & Risk Management - 20
predicts likelihood of future offending based on:
- Historical factors: psychosocial adjustment/ history of violence (10Q) e.g substance abuse, early maladjustment
- Clinical: recent/ current mental health problems (5Qs) eg. impulsivity
- Risk management: ability to adjust to society after prison (5Qs) eg. triggers irl
each Q SCORED 0-2 not present-prevalent
total score /40 - high score = likely to reoffend
Cartwright et al. (2017) investigation on HCR’s accuracy
Cartwright et al. (2017)
investigation on HCR’s accuracy
152 detained males for sexual violent predator laws
aggressive acts recorded over 180 days - records from institution
those who scored highly in HCR20 20.62x more likely to exhibit aggression
moderate sc0re - 3.6x more likely than those who scored low
= HCR is good predictor
- short term study - longitudinal effects may not be captured by HCR 20 as may arise long after
- very rigid measurement scale - mostly based off historical - not reflective of future given personal progression - does not tackle rehabilitation
o’shea et al 2013 - meta analysis
Cartwright et al. (2017)
investigation on HCR’s accuracy
152 detained males for sexual violent predator laws
aggressive acts recorded over 180 days - records from institution
those who scored highly in HCR20 20.62x more likely to exhibit aggression
moderate sc0re - 3.6x more likely than those who scored low
= HCR is good predictor
- short term study - longitudinal effects may not be captured by HCR 20 as may arise long after
- very rigid measurement scale - mostly based off historical - not reflective of future given personal progression - does not address influence of rehabilitation
o’shea et al 2013 - meta analysis
working with law enforcement
improving interviewing:
- witnesses - rapport, open ended qs, not interrupting
- suspects -
accuracy/ reliability of eye witness testimonies
- Loftus + palmer 1974 - leading questions influence perception of memories - reconstructive memories smashed vs contacted - slower vs faster speed
- Kirk Bloodsworth 1984 - (State of Maryland v. Kirk N. Bloodsworth, 1984) - case study
5 eye witnesses identified him as the perpetrator to murder - years later innocent through DNA exoneration - YUILLE AND CUTSHALL 1986 - real life crime + real witnesses, 13 participants reported low response to leading questions - smashed headlight
84.56% of witnesses accurate info 5 months after crime
= eye witnesses are more reliable than experiments often show - could be explained by flashbulb memories which is only present in real life crimes not experiments - unexpected event = effect attention more memorable
- Loftus, Loftus + Messo 1987 - weapon focus effect - impairs memory of peripheral events - focus only on gun
2 conditions: testing identification accuracy when individual held a check (35% correct face) or gun (15%)
unexpected vs expected
explained by 2 theories: - arousal/threat hypothesis: as gun is immediate threat - fixation on weapon - lower peripheral monitoring
- unusual item hypothesis - items not fitting with what is expected in that scene draw attention - attention paid = memory
better alternative =
- DNA testing
- sequential lineup
- double blind - not familiar w case = no leading qs
- remember certainty of identification at lineup - may be more certain later - reconstruct original memory
absolute-relative judgment theory (Wells, 1984)
better witness discrimination - less bias in own memory
- fewer misidentifications (picking known innocent filler suspects)
- less likely to pick out best fit
- but results in more conservative reports - fewer identifications (Palmer & Brewer, 2012).
