forensic psychology Flashcards
what is forensic psychology
the application of psychological knowledge and theories to all aspects of the criminal and civil justice systems including the processes and people
the criminal investigation
pre-trial
trial
post-trial
History of Forensic psychology
James Cattell (1885) - appleseeds question
- witnesses shouldn’t be expected to recall great levels of detail
Alfred Binet (1900) - asked children
- highly misleading questions resulted in poor accuracy
Varendock (1911)
- expert witness
- found children memories inaccurate & suggestible
what is the admissibility criteria of expert testimony
experts must have special knowledge above & beyond average juror and assistance will assist jurors
danger: jurors will pay to much attention to expert witness
recall memory
reporting details of previously witnessed event/person
- tell me what happened
Recognition memory
Reporting whether what is currently being viewed is the same as what has previously been viewed
- identification evidence
estimator variables
variables present at the time of the crime & cannot be changed
- dark lighting
- affect perception
- own race bias - difficulty identifying people of another race
- memory best at optimal arousal
- weapon focus effect
system variables
variables that can be manipulated after the fact and impact accuracy of witnesses
- leading questions
- delay between event and questions (forgetting curve)
what is the misinformation effect
exposure to incorrect information about an event after it has occurred often causes people to incorporate this misinformation into their own memories
- leading questions
- (affected by system variables)
- car crash study (leading questions, emotional wording)
factors affecting
- age
- suggestibility (characteristic)
- source of misinformation
what is false memory research?
- gave students 4 narratives of their childhood experiences , one was false (lost in the shops at 6)
- 25% said they were after suggestive questioning
- done with edited photos and 50% said occured
what are arguments for/against false/repressed memory debate?
For
- memories were repressed due to trauma
Against
- Loftus believed therapists implanted false memories of sexual abuse in patients
- people don’t think abuse is traumatic as child but realise it later on
ID inaccuracy Surveyed justice officials
US justice officials reported that over 70% thought erroneous confications occured in less than 1% of cases
- if ture 7,500 wrongful convictions
ID inaccuracy DNA exoneration cases
advances in DNA evidence has proved innocence of convicted inmates
- 72% of these cases based on mistaken ID
ID inaccuracy empirical studies
field studies (high ecological, low experiment control)
- 41% correct
- 35% false
- no difference with those trained in ID
lab studies (low ecological, high experiment control)
- false ID correlated with high witness confidence
showup lineup
one person containing only the suspect
- high rate false ID
composition of lineups
foils match verbal description from witness but vary from suspect in ways not mentioned by witness
format of lineups
live - expensive difficult to arrange
photos - larger database
mugshot - used in early stages
same person can’t appear in multiple line ups due to unconscious transference
instructions of lineup
witness told perpetrator may or may not be in lineup
double blind procedure
simultaneous lineup vs sequential lineup
simultaneous
- all lineup members at the same time
- relative judgement
sequential
- presented one at a time (yes/no given before move on)
- fewer false ID & fewer correct ID
- absolute judgment
what is profiling?
identifying the major personality & behavioural characteristics or an individual based upon analysis of the crimes they have committed
- uses demographics, statistics, personality
- used in cases of serial homicide & rape
deductive criminal profiling
profiling the background characteristics of an unknown offender based on evidence left at crime scene
relies on logical reasoning… but underlying logic can sometimes be faults
inductive criminal profiling
profiling the background characteristics of an unknown offender based on what we know about other solved cases
relies on a determination of how likely offenders are similar to each other
FBI approach
- interviewed 36 convicted sexually motivated murderers
- categorised into organised and disorganised
- deductive crime scene and way crime was committed reveals characteristics
- binary model, cannot account for those with mix of both traits
Statistical approach
- data collected from solved crimes and analysed using statistics
- each crime has different probabilities based on different characteristics
- only as good as data given (small sample size)
geographic profiling
- analysis of crime scene locations for serial crime
- assumes offenders don’t travel far yet don’t go to close
- doesn’t work for burglary
- often quite accurate
deception
a successful or unsuccessful deliberate attempt without forewarning, to create in another belief which the communicator considers to be untrure
what are polygraphs?
- measures physiological change not lies
- assumption telling a lie is more stressful than telling the truth
- not admissible in Aus court
Relevant/Irrelevant polygraph
- asks questions relevant to the crime and irrelevant to the crime
- assumes guilty people will respond more strongly when lying about the relevant questions
- innocent people know relevant questions and will worry about their responses (creating stress)
- lot’s of false positives, no longer used
Control question test
- uses irrelevant, relevant and control questions
- include control questions an innocent person would find stressful to answer
- phase 1: yes no questions previously discussed with all three types ask suspect to lie for some control questions to create a baseline
- phase 2: simulation test (often card trick) used to trick suspect into believing that the polygraph can detect lies
- phase 3: ask three types of questions over & over
- phase 4: score & quantify (global or numerical)
- false positives
guilty knowledge test
- asks questions only guilty would know the answer to
- asks multiple choice questions (1 answer correct) assumes guilty will react strongly to correct information
- innocent will respond same to all because they don’t know the answer
- innocent person will likely have higher accuracy due to chance
- false negatives
- need sufficient info that public does not know
nine steps to interrogation
1 postivie confronation
* direct presentation of real or fake evidence
* repeated accusations
2 theme development
* developed to justify the crime
* minimisation - emotional, not your fault
* macimisation - nonemotional, intimidating
3 handling denials
* stop suspects repeated denials due to unfounded assumptions (more they deny harder to get a confession)
4 overcoming objections
* showing understanding and returning to theme (2)
5 retaining syspects attenion
* moving physically closer
6 handling suspects passive mood
* creates a remorseful mood
* focuses on possible reasons for crime
7 creating an opportunity to confess
* give opportunity to provide explanation for the crime
8 oral confession
* development of inital confession
* brief questions asked
9 converting oral confession into written one
concerns with nine step approach
- officers enter with belief suspect is guilty
- unethical trickery and deceit
- boomerang effect
- police may think its ok to bluff in other circumstances
- may lead to false confessions
voluntary false confessions
without prompting by police
- desire for notoriety
- attempt to protect real offender
Coerced-compliant false confessions
- in response to a desire to escape further interrogation, gain reward or escape punishment
- confessor knows they are innocent & most common
Coerced-internalised confessions
- results from highly suggestive interrogations
- confessor comes to believe that they did commit the crime
Alt key test in laboratory for false confessions
- more compliance with false evidence
- more internalised told to type fast (reduced memory)
replicated study with consequences if didn’t sign
- 82% signed
- 42% internalised
- 58% compliant
PEACE model for interrogation
planning & preparation
- know all the facts
engage & explain
- encourage suspects perspective & inform of rights
account
- ask questions & mentions inconsistencies
closure
- give suspect summary
evaluation
- conversation management to secure confession
peremptory challenges
allowed to reject (3 in australia) people without a reason
challenge for cause
unlimited number by both parties, to throw out based on a reason
stages involved in jury verdict (with psychological research)
1 listening to evidence
- note taking & asking questions
2 disregarding inadmissible evidence
- instruction draws attention making it hard to forget
3 judges instructions
- jurors understand less than 50%
- mixed findings for proving written copy to jurors
4 Juror decision making
- evidence organized into a coherent whole (active interpretation)
5 jury deliberation
- leniency bias (towards acquittal)
- group polarisation following discussion
- minority influence not likely
