What is Eye Witness testimony?video clip

What is Eye Witness testimony?video clip

What is EWT?Legal term for witnesses who give evidence

in court concerning the identity of a suspect.

Three stages of EWT

Eyewitness testimony

Loftus and Palmer (1974)

Do leading questions distort the accuracy of EWT?Aim: to investigate the accuracy of memory

after witnessing a car accident, in particular to see if leading questions

distort the accuracy of an eyewitnesses’ immediate recall.

ProceduresForty-five students Shown films of traffic accidents. Questions afterwards included a critical one

about speed of car containing the word ‘hit’, ‘smashed’, ‘collided’, ‘bumped’ or ‘contacted’.

FindingsVerb Mean Speed estimate

Smashed 40.8

Collided 39.3

Bumped 38.1

Hit 34.0

Contacted 31.8

FindingsThe group with ‘smashed’ estimated the

highest speed (about 41 m.p.h.).The group given the word ‘contacted’

estimated the lowest speed (about 30 m.p.h.).

ConclusionsLeading questions (post-event information)

can have a significant effect on memory (could be on original memory or recall).

Criticisms(1) Lacks validity because it is not true to real life and

lacks realism.Other research has found that recall is more accurate

in real life (Yuille and Cutshall, 1986).This may be because people don’t take the experiment

seriously or are not as emotionally aroused as in real accident.

(2) It has experimental control and therefore some validity.

This is because the IV (verb) effects the DV ( estimate. This demonstrates a causal relationship between leading questions and recall of information.

RMA Control group does not receive the

independent variable. But it’s performance is assessed on the dependent variable.

The results can be compared with the experimental group.

The control group serves as a baseline measure.

ValidityLab experiments may not be taken seriouslyParticipants are not emotionally involved.Foster et al better identification in real life

set up.

There is research support.Loftus and Palmer (1974)Procedures: 3 groups of participants: They were asked a series of questions including did you see any broken glass. group 1: smashed, group 2:hit; group

3: no questions about speed of

vehicle.

Verb condition

smashed hit control

Yes 16 7 6

No 34 43 44

Loftus and Palmer (1974)Findings: those given ‘smashed’ were more

likely to recollect broken glass (there was none).

Conclusions: Shows a significant effect of post-event information on later recall of events.

However…Loftus (1979b)Finding: when shown a series of pictures of

a man stealing a red wallet from a women’s hand bag, 98% correctly identified the colour. Furthermore despite later being given an erroneous description of the wallet as brown, participants persisted in describing the wallet as red.

Conclusions:This shows that we may have good recall for

important information, and the recall of such information may not be distorted even by misleading information.

ARMED ARMED ROBBERYROBBERY

EWT in real lifeYuille and Cutshall 1986 interviewed 13

people who had witnessed an armed robbery in Canada.

The interviews took place more than 4 months after the crime and included two misleading questions.

Yuille and Cutshall 1986Findings: Despite these questions, the

witnesses provided accurate recall that matched their initial detailed reports.

Conclusions:This suggests that post event information

may not affect memory in real life.This study also shows that EWT can be very

reliable.

Individual DifferencesLinsday 1990 identified two sources of

misinformation.Observation of event itselfSubsequent suggestions

Schacter et al 1991 found that elderly people have difficulty remembering the source of their information, but not the content.

This group is more prone to the effect of misleading information.

Individual differencesWells and Olsen 2003 found no differences

between males and females despite a different focus.

Real worldWells and Olsen 2003 found that EWT

testimony may be mistaken, this is supported by DNA exoneration cases.

Post event information

Broken glass Misleading questions affect storeage.Loftus stop and yieldBekerian and Bowers

Review Activity 4 p 27 fill in the blanks.Explain why studies of EWT have been

criticised as lacking in validity. 5 marks. (spec 1)

task 3 extended writing. 12 marks

AnxietyAge of witness

AnxietyDeffenbacher et al meta analysis shoed

anxiety reduced accuracy of EWT.Christianson and Hubinette 1993 foudn

anxiety increased accuarcy in real life bank robberies

Yerkes-Dodson law: accuracy is best under moderate arousal.

WEAPONS FOCUSWEAPONS FOCUS

Weapons focusLoftus 1979a. Identified weapons focus.

There were 2 conditions:In both conditions participants heard a

discussion in an adjoining room.In both condition 1 a man emerged

holding a pen with grease on his hands.In condition 2 the discussion was more

heating and a man emerged holding a paper knife covered in blood.

findingsWhen asked to identify the man from 50

photos, participants in condition 1 were 49% accurate compared with 33% accuracy in condition 1.

conclusionsThis suggests that the weapon may have

distracted attention from the man and might explain why eyewitnesses sometimes have poor recall for certain details of a crime.

Meta analysis Steblay 1992 found that the presence of a

weapon reduces the chance of correct identification of person holding the weapon.

Loftus 1987 monitored eye movements and found that the presence of the weapon causess attention to be physically drawn towards the weapon and away from the face.

RMMeta analysis

ApplicationsRiniolo et al EWT from titanic was accurate.

Age of witnessYarney describe young woman , younger

participants more confident no age differences.

Mermon et al older people less accurate when delay was one week.

Own age bias. Anastasi and Rhodes.

Clip to viewBasketball.

Individual differences

Alcohol impairs attention. Clifasefi et al 2006

Lab v field experiments.

Laboratory experimentIV manipulated to observe effect on DV,

controlled.(+) Can draw causal conclusion.(+) Confounding variables minimized.(+) Can be easily replicated. (-) Artificial, contrived situation.(-) Investigator and participant effects.

Field experimentInvestigate causal relationships in more

natural surroundings. IV directly manipulated by experimenter to

observe effect on DV. (+) Usually higher ecological validity than

lab experiment.(+) Avoids some participant effects.(-) Less control.(-) More time-consuming.

To doRM 3.9RM 3.10