eyewitness memory Flashcards
define eyewtiness testimony
Eyewitness testimony -account given by people of an event they have witnessed
outline the memory proccesses involved in EWT
Crime= encoding
Storage
Investigating= retrieval
what is a photo line up?
fillers and only 1 suspect fillers known to be innocent
Outline the issues with photoline ups
19 84- Jenifer Thompson rape Later picked up Cotton Costly false ID Sentenced to life +54 years Served 11 years before exonerated.
Not picked out of a line up
Bundy- killed at least 9 more
Costly miss
what do you want in ROC in line ups?
high descriminability
what is the differcne between descriminabiltiy and reliability?
descriminability:
Ability to distinguish innocent from guilty suspects
Measured by receiver operating (ROC) characteristic analysis
Policymakers
relaibility:
Likelihood identified suspect is the perpetrator
Measured by confidenceaccuracy characteristic (CAC) analysis
Judges and jurors
are eyewitnesses unreliable?
Loftus & Palmer (1974)
Participants: • N = 150 • 3 groups: Smashed, Hit, Control
Procedure: • Watch video of car accident • Answer questions about the accident • “how fast were the cars going…” • “Did you see any broken glass?”
Memory Is malleable
ID 2- contminated
Pay attnetion only to the 2nd identification
explain the issues with eyewtiness confidence and reliability
btained court and police records for 161 DNA exoneration cases.
In 57% of those cases, the eyewitness was initially uncertain about his or her identification.
A witness who expresses low confidence is effectively saying “there is a good chance I am making an error”
Thompson initially chose two pictures, one of which was Cotton.
She examined those two pictures for 4-5 minutes and then said: “Yeah. This is the one…I think this is the guy.”
Thompson’s low-confidence initial ID illustrates how reliable eyewitness memory is.
outline influnces that can effect EWT at tim of encoding
weapon focis effect Exposure Duration cross-race bias- remember faces of same race more Stress Distinctiveness of Perpetrator
outline a study into CAC and ROC analysis
Palmer, Brewer, Weber & Nagesh(2013)
Participants: N = 986
Procedure: Study Phase: View a target for 5 s or 90 s Delay Test Phase: 6-person simultaneous lineup
• ½ target-present lineups and ½ target-absent lineups • Collect confidence ratings on 100-point scale
outline the influcnes that can effect EWT at storage stage
verbal overshadowing -effects of verbalisation
Appearance change: change in looks
Retention interval: time between crime and ID
co-witness effects: memory collaberation
outtline a study into verbal overshadowing
Wilson, Seale-Carlisle & Mickes (in prep)
Participants: N = 700
Procedure: Study Phase: View video of crime Delay Describe perpetrator or control task Test Phase: 6-person simultaneous lineup • ½ target-present lineups and ½ target-absent lineups • Collect confidence ratings on 7-point scale
outline influences effecting EWT at retrieval stage
filler selection -line up members
lineup presentation - SIM, SEQ, Show up
blind admin- doesn’t show suspect
line up instructions “may or may not be there”
give a study into line up presentation
Participants: N = 600
Procedure: Study Phase: View video of crime Delay Test Phase:
• 6-person simultaneous or sequential lineup • ½ target-present & ½ target-absent lineups
• Collect confidence ratings on 100-point scale
Mickes, Flowe& Wixted (2012)
explain the differecne bwtween estimator and system varaibles
System variables are those that are (or can be) under the control of the justice system, whereas estimator variables cannot be controlled by the justice system.
Examples of system variables include factors such as the instructions given to eyewitnesses prior to their viewing a lineup or the number of people who are used in a lineup.
Examples of estimator variables include factors such as how good a view the eyewitness had of the perpetrator during the crime or whether the witness and perpetrator were of the same or different race.
