Week 1 Flashcards
What is Investigative Psychology?
Investigative Psychology is the application of psychological principles and research to the investigation of crime.
Treating memory like a crime scene
Justice system must optimise ‘system variables’ (Wells, 1979) to:
-enhance the completeness and accuracy of the complainant’s account
Memory is not like a video recording! Events are reconstructed using stored memory and our knowledge about the world
Overview:
witness reports
proivde major leads in an investigation how often?
36% ‘always’ or almost always’
51% ‘usually’ (Kebbell & Milne, 1998)
Estimator variables
Estimator variables are external factors that influence eyewitness testimony and how accurate the recollection of the events are. Estimator variables cannot be controlled by others.
Examples are how good the witness’ vision is, how close the witness was to the event, and how clear the weather and visual conditions were on that day. These variables are influential to the testimony of the witness and cannot be controlled by legal professionals.
System variables
Things that forensic investigators can influence.
Examples of system variables include how and when a police lineup is arranged and instructions given to the witness.
Variables controlled within an actual court case are system variables (Wells, Memon, & Penrod, 2006). System variables are divided into two categories; interviewing eyewitnesses and identification of suspects. Interviewing eyewitnesses is the process that involves recall memory and identification of suspects involves recognition memory (Wells et al., 2006).
System variable research has focused primarily on four factors, namely the instructions to eyewitnesses, the content of a lineup, the presentation procedures used during the lineup, and the behaviors of the lineup administrator.
The importance of eyewitnesses
D.N.A. testing and other research indicates that inaccurate eyewitness evidence is the major factor responsible for false convictions (Huff, Rattner and Sagarin, 1996).
Memory Processes
Human memory is not like a video camera (Cutler and Penrod, 1995)
Basket-ball example (selective attention/invisible gorrilla)
For a memory to recalled it must go through three stages:
encoding
storage
retrieval
Encoding
The process of storing or representing information in memory
Depends on where attention is perceived
We cannot take in all the information in our environment
Information to which we do not actively attend is rarely encoded
Example: Daniel Morcombe case
Storage
As we do not encode everything we have gaps in our memory
We may “fill-in” the gaps to fit in with our attitudes, beliefs and expectations
External sources may be incorporated into memory (e.g., told someone had a moustache)
Often unable to distinguish the source of memories (source amnesia)
Example: Newcastle shooting
Retrieval
We cannot claim to have successfully remembered material unless we have recalled it
Retrieval cues are important here
eg. Joke endings Security guard (?)
Example: Try to recall as many words as possible from the cue _ _ _ _ I _ _
vs cue:
Now try to recall as many words as possible from the cue _ _ _ _ I N G
Recognition versus Recall
Recall- when we have to call something up cold
Recognition- when the information to be remembered is presented to us and we have to decide whether we have seen it before
Identification accuracy
Dwayne Scruggs sentenced to 40 years for rape (served 7.5) based on victim id and the similarity of his boots.
Connors, E., Lundregan, T., Miller, N., & McEwen, T. (1996). Convicted
by juries, exonerated by science: Case studies in the use of DNA
evidence to establish innocence after trial. Washington, DC: References U.S. Department of Justice.
Line Ups:
Four recommended rules (Wells, Small, Penrod, Malpas, Fulero, & Brimacombe, 1998)
Rule 1
Rule 1: Who conducts the lineup
The person who conducts the lineup should not be aware of which member of the lineup or photospread is the suspect
Lineup as experiment analogy
Clever Hans, rat mazes
State v’s Washington
Prevents feedback
LINE UPS
Four recommended rules
Rule 2
Eyewitnesses should be told explicitly that the person in question might not be in the lineup or photospread and therefore should not feel that they must make an identification.
They should also be told that the person administering the lineup does not know which person is the suspect in the case.
Four recommended rules rule 2 contd? less likely to... encourages? Selective effect? prevents..?
Less likely to make a false id if they know the offender may not be there (Malpass & Devine, 1981)
Encourages not to make a relative judgement
Selective effect- no appreciable reduction in culprit present lineups (Steblay, 1997)
Prevents witnesses from looking for cues
Lineup Rule Recomendations
Rule 3 Structure of the lineup or photospread
The suspect should not stand out in the lineup or photospread as being different from the distractors based on the eyewitness’s previous description of the culprit or based on other factors that would draw extra attention to the suspect.
line up rule recommendations
rule 3 part 2: godamnit I hate mylife
important that?
show ups are?
can be tested using?
distractors should not…?
Important that the research hypothesis is not conveyed to the participant (e.g., if only the suspect has the described clothes)
Show-ups not acceptable
Can be tested using a mock-witness procedure (Malpas, 1981)
Selecting distractors that look like the suspect is not desirable as you eventually could end up with clones
Line ups Rule 3 continued:
Misfit between…
unique non-described….
Misfit between suspect and description:
- -E.g. if evidence suggests someone else
- –Default to the suspect description
Unique non-described features of the suspect
—-Does not matter unless he stands out in such a way as to appear guilty
Four recommended rules
Rule 3 Continued again FUCK
Common non-described features
E.g., default to clean shaven if not mentioned
If description is so unique, e.g., scar or tattoo then a lineup may not be necessary
Line-ups:
RULE 4
Obtaining Confidence Judgements
A clear statement should be taken from the eyewitness at the time of the identification and prior to any feedback as to his or her confidence that the identified person is the actual culprit.
Rule 4: confidence judgements
continued
Confidence is a powerful factor in determining accuracy
Confidence may increase due to post-event factors
Require a record
What do you want from an eyewitness?
Kebbell & Wagstaff (1998) state it is to:
Identify offence
Identify offender
Remove inappropriate defence
Accuracy of eyewitness accounts
Factors concerning the crime- can be remembered from the mnemonic “ADVOKATE”
(A)dvokate
Amount of…
Amount of time under observation
Alexander & Lane (1971) presented slides for 10 s or 32 s. Correct identifications were made 47% of the time with the short exposure and 58% of the time with the longer exposure
a(D)vokate
how far?
Distance
The further away the more difficult to remember details.
Wagenaar & van der Schrier (1994) found identifications became more dubious when the distance between the witness and target was over 15 m
ad(V)okate
can you see it?
The time of day and quality of streetlighting will also have an impact.
Wagenaar & van der Schrier (1994) found identification was often inaccurate at light levels of less than 5 lux.
adv(O)kate
whats in the way?
Obstructions
If something obstructs the witness’s view, it will prevent the witness seeing, encoding and retrieving the information
Wells & Murray (1983) showed a 5 min video with the target occluded for 20, 50, or 80% of the time
Estimates of the occlusion were 10.6%, 21.3%, and 53.5% respectively
advo(K)ate
do I know you?
Known or seen before
If a witness has previously seen an offender he or she will be more able to provide details
Bruce (1982) showed familiar and unfamiliar pictures. Accuracy rate was 95% for familiar and 55% for unfamiliar
advok(A)te
why remember?
Any reason to remember
We are more likely to remember memorable information.
Pezdek & Prull (1993 found that recognition memory for sexually explicit
content is better than memory for nonexplicit content, and
that this difference is more pronounced when the utterance is
contextually incongruous
“I can’t keep my eyes off your sensuous moist lips” More likely to be remembered in an office situation than a bar situation
advoka(T)e
delay vs accuracy
Time lapse
The longer the delay the less complete and accurate the memory will be
Ebbinghaus (1885) memory of nonsense symbols
advokat(E)
material discrepancies
Errors or material discrepancies
Not always the case. For example, Wells & Leippe (1981) found that accuracy of peripheral information not related to accuracy of identification
advokate V
violence/presence of a weapon
Violence and presence of a weapon
The more intense something is the more likely it is to have an impact on us and we are to remember it
Keep recalling the event (Christianson, 1992)
“Weapon focus” When a weapon is used the witness is likely to focus on that weapon to the detriment of their memory for other factors
