Ch6: Eye Witness Identification and Testimony

memory processes

encoding: gathering information and putting in a form that can be held in memory,

storage: holding the encoded information in the brain over time

retrieval: accessing and pulling out the stored information at a later time

yerkes-dodson law

looking at the relationship between stress/emotional arousal and memory

low arousal-weak performance

medium arousal- peak

high arousal- weak

viewing conditions

might be dark, might not have glasses, witnesses might be hiding, etc

time estimates and exposure

people are usually not good at estimating time

juries opinion on seeing suspect for 20 secs vs 5 mins

the more stressful the experience, the longer people estimate seeing the suspect in front of them

weapon focus

if someone has a gun, eyes usually are focused on that

when a gun was in the scene, witness was less likely to accurately identify the suspect

even in cases of celery, there was a weapon focus

types of identification

in-person line up

walk-through or show-up

photo array

selection of foils in line-ups

photos can be taken from divers license

mugshots

in lineups other police officers or people chosen on the street

simultaneous vs. sequential presentation

research shows showing potential suspects on at at time is better

if you look at more than one, you start to compare and it feels like it’s a multiple choice

target present vs target absent line-ups

police are always going to have a line-up with a suspect

in research, shown if the suspect really isn’t apart of the case, the witness will choose someone regardless

administrator’s potential bias

if the administrator knowns who the suspect is, could purposefully or accidently point the witness towards that photo

experimenter bias- and double-blind procedures

cross-race identifications

people are used to looking at people of the same race

might have a harder time identifying people outside of their race

maybe won’t pay attention to details etc

called the cross-race effect or own-race bias

post-event information

if there are two witnesses police will usually separate them right away

they can influence and effect the others memories

photo-biased identification

making the identification multiple times

in the second lineup, all the fillers have been changed except the suspect, does the person choose the suspect because they have been shown twice?

unconscious transference

the mistaken recollection of a person seen in one situation as the person seen in a different situation

confidence and certainty of eyewitness

confidence over time tends to increase

the increase in confidence doesn’t mean it’s correct

suggestibility

degree to which encoding, storage, retrieval, and reporting of events can be influenced by a range of internal and external factors

suggestive questioning

what was the perpetrator wearing vs what color mask were they wearing

children as eyewitnesses

suggestibility in children

pressure and rewards during questioning

co-witness statements

confirming the questioner’s belief

adults as authority figures

memory traces

the biochemical representations of experiences in the brain- appear to deteriorate with time

distortion of a memory can occur during the process of retrieval

research on eyewitness and conviction

in 347 cases in which the only evidence was eyewitness testimony

74% of those cases the defendant was convicted

in 49% there was only one eyewitness

stats on eyewitness

mistaken eyewitness leads to more wrongful convictions than any other type of evidence

mistaken identifications played a role in 71% of cases where wrongly convicted persons were released from prison because DNA testing later proved their innocence

the Manson criteria

the courts have emphasized five factors at should be taken into account when evaluating the accuracy of an eyewitness’s identification

1. the witness’s opportunity to view the perpetrator

2. the witness’s level of attention

3. the accuracy of the witness’s previous description of the offender

4. the witness’s degree of certainty

5. the amount of time between witnessing the crime and making the identification

voir dire

intended to expose potentially biased jurors so that attorneys can dismiss them

jurors thoughts on eyewitness

research shows that jurors place undue faith in the reliability of eyewitnesses, place too much weight on eyewitness confidence, and are not very skilled at distinguishing between accurate and inaccurate eyewitnesses

postidentificaiton feedback effect

tendency for biased feedback or distort the memory of eyewitnesses

those who received positive feedback were more confident

cognitive dissonance

predicts that once you commit yourself to a particular course of action, you will become motivated to justify that course of action

once you’ve committed yourself to a particular identification, you become increasingly certain that you picked our the right person

children and eyewitness

children are only lightly less accurate than adults when presented with lineups or photo spreads if the true perpetrator is present in the lineup

if the true perpetrator is absent, children do worse

children have greater suggestibility

estimator variables

variables that are outside the control of the legal system

who witnesses a crime, how carefully, or the race

system variables

factors that are under the control of the justice system

how a witness is questioned and how lineups are constructed

nine recommendations to reduce the number of mistaken identifications

1. prelineup interviews

2. evidence based grounds for putting suspects in lineups

3. double-blind lineups

4. appropriate lineup fillers

5. pre lineup instructions to eyewitnesses

6. video recording

7. avoiding repeated identification procedures with the same witness and suspect

8. Avoiding the use of showups

9. Expert testimony

prelineup interviews

police should interview eyewitnesses as soon as possible and the interview should be recorded

include verbal descriptions, information about prior familiarity, self-reports about level of attention, and self-reports about viewing conditions at the time of the crime

warn witness not to discuss with other co-witnesses and not to identify the culprit on their own

evidence based grounds for putting suspects in lineups

• A suspect’s unique fit to a specific description given by an eyewitness (e.g., “blue teardrop tattoo under left eye” or “moon-shaped scar on chin”).

• Self-incriminating statements by the suspect.

• The suspect’s possession of materials linked to the crime, along with a fit to the general physical description given by an eyewitness.

• Investigators’ knowledge that the suspect was in the area of the crime around the time of the crime, along with a fit to the general physical description given by an eyewitness.

• Physical evidence at the crime scene linked to the suspect, along with a fit to the general physical description given by an eyewitness.

• A unique pattern to the crime that is known to be associated with the suspect, along with a fit to the general physical description given by an eyewitness.

double blind lineups

the administrator nor the witness should know who the suspect is in the lineup

appropriate lineup fillers

all of the people in the lineup should closely resemble each other and all should match the witness’s verbal descriptions of the culprit

pre lineup instructions to eyewitnesses

The eyewitness should be instructed that (

• a) the lineup administrator does not know which person is the suspect and which persons are fillers

• b) the culprit might not be in the lineup at all, so the correct answer might be “not present” or “none of these”

• c) if they feel unable to make a decision they have the option of responding “don’t know”;

• d) after making a decision they will be asked to state how confident they are in that decision

• e) the investigation will continue even if no identification is made

bias-reducing instructions remove the presumption that the witness is obliged to choose someone from the available options

obtaining an immediate postlineup confidence statement

obtain a clear statement about how confident the witness is that he or she identified the right person

must be taken immediately after the witness identifies the culprit and before any feedback is given to the witness

video recording

video taping of the prelineup instructions and confidence statement

avoiding repeated identification procedures with the same witness and suspect

earlier identification procedures can contaminate the later procedures

avoiding the use of showups

showups tend to be highly suggestive, indicating ot eyewitnesses that the police already believe the person is guiltye

expert testimony

expert testimony is particularly helpful when eyewitness identification procedures significantly deviate from the nine recommendations summarized above

expert testimony findings

it sensitized jurors to the importance of viewing and lineup conditions that compromise or enhance accuracy

it led jurors to put less credence in witness confidence as an indicator of accuracy

techniques for refreshing the memories of witnesses

1. hypnosis: people usually recall more information when they are hypnotized then when they are not (hypnotic hypermnesia)

2. cognitive interview: subtle step-by-step procedure designed to relax the witness and to mentally reinstate the context surrounding the crime with the goal of improving retrieval and accurate information