Forensic Test 4 Flashcards
the development of exonerations correspond with the development of
DNA analysis
90% of exonerations come from physical evidence
how many exonerations per year by innocence projects does:
- Canada
- US
US - 367 (255 due to faulty eye witness, 69% of all cases)
Canada - 24
Explain the study by P. Delvin involving eye-witness testimony
Looked at 2116 court cases
- in 45% of cases a suspect was picked from a lineup
- 90% of the subjects picked from the lineup were brought to persecution
- In 347 of those cases, eyewitness testimony was the only evidence
- yet, 75% of the cases that only had prosecution were convicted
What happened in the study of a mock jury that looked at how much eyewitness evidence impacts convictions
What is the take away from this study?
Corner store robbery and murder
Conviction rates based on given evidence:
18% : Given short description of facts, circumstantial evidence, defence rebuttal
72%: When eyewitness ID’d the defendant
68% : When eyewitness evidence was undermined (“Witness wasn’t wearing their glasses)
Take away: Just getting eye witness evidence in, even if not reliable, is very important for prosecution
Explain the Porter, Yuille & Lehman (1999) study about recovered memories
- Tested false memory implementation for emotional events
- Examine whether we can tell what are false memories and what are genuine memories
- 77 participants
- Researchers got parents to fill out survey which identify the history of the child so researchers could come up with one real memory, one fabricated memory, and one memory for implantation
- participants believe it is a memory task where they are asked to remember memory details and their parents will be called later to corroborate them
- researcher says both are real, take time to answer, use social pressure, guided imagery
- at end, told that if they can convince a third party that a new event, given to participant in an envelope, happened/
Results: 75/77 recalled real event
20/77 recalled false memory with all criteria
- 34 had no recall whatsoever
- when telling rela event - tell in third person
detail - most in fabricated, lowest in implanted
- don’t show confidence for fabricated
Asked to bet if individually, the memory was genuine
- 31% believe false memory is real
- 35% bet implanted memory is real
92% were correct when told to guess which is real if only one is real and other is fake
What is a false memory
When you believe something happened that didn’t
What is repression
When the event occurred, your mind locked it away in a box. You have no memory of it even at the time of it happenin
What is a recovered memory
A repressed memory that is unlocked
- idea that it is pristine since it hasn’t gone through decay or interference
What is memory suppression
When something happened, and you know it happened at the time of the event, but you don’t want to think about it
What are flashbulb memories
an impression may be so exciting emotionally as to leave a scar on the cerebral tissues
How can we test flashbulb memories
we can look at events that create flashbulb memories for a large amount of people
- 9/11
- Inauguration of O/Bama
- Challenger explosion
the exact same techniques used to recover memories are also used to ____
induce memories
- this makes I hard to determine where these memories are actually coming from
When did false memory research take off? What disorder began taking off as a concept, resulting in increased diagnoses during this time?
1980s
Multiple personality disorder
- theory: repressed memory locked away in a personality
What is some evidence in history that ppl can induce disorders or behaviour?
demonic possession - demonic position cases tend to present symptoms of the persons own proposed religion
Certain communities suddenly have higher incidence of Multiple Personality Disorders or another disorder, - seems to be a single therapist
Explain the study by Patihis (2014) That looked at professionals’ beliefs in repressed/supressed memories
Less belief that repressed memories can be retrieved in therapy accurately
From most to least belief in repressed memories and recovery: General public, alternative therapists’, clinical psychologist practitioners, clinical psychologist researchers
Maybe they believe in repressed memories but when recovery of memory is attempted, it can easily be done wrong to induce a memory
Alternative therapists (anyone who isn’t a clinical therapist or psychologist)
Why was the challenger such a huge event?
christa mcauliffe - in 1960/70s ppl going to moon schools would show the launches of rockets - these celebrities that they became, instrumental in getting nasa funding - the challenger was an attempt to bring back all that excitement, she was a school teacher, there was a contest to be the first non astronaut to go to space - shown at all schools -
Explain the study on the challenger explosion flashbulb memory by Neisser and Harsch
A study of memories of the challenger disaster
1992 - they wanted to test their memory later on
Question them on day of disaster and wait for 2 years and 44 of 106 students answer another questionnaire - about elements of that flashbulb memory
The day after - that info the researchers used as ground truth
Then back 2 years later they asked the same questions and they wanted to see if answers matched
Each question was also accompanied by a confidence scale 1-5
25% (11) claimed to remember seeing the questionnaire before but most did claim they had this flashbulb memory
After an analysis - memories weren’t great - researchers wanted to see if they could help them match up -
Asked them to answer a bunch of questions about the event to get details about everything they remembered
Also shown original questionnaire they filled out and signed 2 years earlier
the majority got nothing rightdespite confidence ratings on being right were very very high
So: flashbulb memory doesn’t seem to be very good
Follow up interview - things dont improve - memory got worse
When shown their own questionnaire they were shocked and were not willing to change their recollection of it now - the way they saw it now was the way it actually happened
Some didn’t even believe they themselves had filled out that questionnaire
Ratings of vividness and intensity of memory nd whether the statements were accurate
Only auditory seemed to be a significant correlation as being accurate
The stories ppl were telling were that stories were converging -
On TV you couldn’t help but see the explosion everyday, so even though most people had found out through a friend, or overheard it, there subsequent memory of what it was first finding out about it watching TV
what has the US courts told ppl about confidence? is it right?
they told ppl more they tell juries they can use witnesss confidence as some evidence related to the accuracy of their testimony confidence = more likely telling the truth
not right based on studies, particularly the one with the challenger flashbulb memories
When does confidence play a role in the accuracy of testimony
only directly after the event. in initial police interviews that are unbiased
how do we treat the fragility of eyewitness testimony?
not well
- not treated with same care as physical evidence (protect the scene, don’t contaminate anything)
- eyewitness testimony usually contaminated by:
- query construction
- leaking
- poor recording
- rookies who want to find out things from witnesses
what is the best interview style for questioning a witness
the cognitive interview
interview vs interrogration
interview - any time police are talking to someone
interrogation - talking to a suspect
difference of talking during these:
- during interrogation sometimes rapport building is used as the ol is confession
Explain the cognitive interview
- Rapport building
- Supportive interviewer behaviour - let them tell their story then later go back and ask questions
- Transfer of control - let witness control the interview - everyone tells stories differently
- Focused retrieval - only after the previous steps do you go to this
- Witness-compatible questioning - when asking questions you want to try that they are in a style that matches how the witness thinks about things
recommendations for lineups
double-blind administration
the different lineup by brewer et al. (results in best accuracy)
What is: A Different Lineup
Brewer et al 2012
Used just confidence judgments on how confident you are this is the perp under deadline pressure
Get photos sequentially
Relative confidence? Which one are you most confidence about? That’s the perpetrator
Accuracy increased from 11% to 38%
Still, no one uses it
Rejected by prosecutors - all these 6s and 5s goes to the defense - goes back to whole story of portraying more confidence than you have - the defense could say they picked this person and say this is almost just as good
describe the stages/ processes of memory
encoding (when you are perceiving and paying attention to something), then short-term, then long-term (where it can be retrieved as needed
how does stress influence memory
it can actually result in poorer memory - contrary to popular belief