6 - Factors Affecting EWT: Misleading Info + Anxiety Flashcards
What is an eyewitness testimony (EWT)?
Ability of individuals to remember + retell details of events (often crimes) they have observed
What two things can affect the accuracy of an EWT?
- Misleading info (leading questions + post-event discussion)
- Anxiety
What is misleading information?
Incorrect info given to the eyewitness, usually after the event, that may affect the accuracy of their EWT
What are the two aspects of misleading info we look at?
- Leading questions
- Post-event discussion (PED)
What are leading questions?
Questions that, because of the way they are phrased, encourage a certain answer (therefore having potential to affect EWT accuracy)
Is misleading info thought to increase or decrease the accuracy of EWT?
Decrease - individuals begin to recall things they didn’t see
In what two ways are leading questions thought to affect the accuracy of an EWT?
- Response-bias explanation
- Substitution explanation
What is the response-bias explanation?
- Explanation of how leading questions impact EWT accuracy
- Wording of question has no enduring effect on EW’s memory, but influences the answer they give
What is the substitution explanation?
- Explanation of how leading questions impact EWT accuracy
- Wording of question affects EW’s memory of an event
Who did a study to investigate the impact of leading questions on EWT accuracy? When?
Loftus + Palmer (1974)
Outline Loftus + Palmer’s 1974 research on leading questions
Aim:
- To investigate the effect of leading questions on the accuracy of EWTs
Procedure:
- Lab experiment
- 45 American students
- Showed film clip about car accident, then asked questions about speed
- 5 independent groups of ppts, each given different verb in critical question about speed: hit, contacted, bumped, collided, smashed
Findings:
- ‘Contacted’ condition reported lowest mean speed est: 31.8mph
- ‘Smashed’ condition reported highest mean speed est: 40.5mph
Conclusion:
- Leading questions have ability to affect EWT (in this case most likely because of response-bias explanation: memory not changed)
What did Loftus + Palmer’s second 1974 experiment support? Why?
- Supported: leading questions causing substitution explanation
- Why: when repeated experiment + asked ppts to recall the event, people in the ‘smashed’ condition were most likely to report broken glass, even though there wasn’t any (memory changed)
What is post-event discussion (PED)?
EWs discussing their observation of an event with other people or co-witnesses (therefore having potential of affecting EWT accuracy)
What phenomenon is post-event discussion thought to cause?
Memory contamination (info from other witnesses mixes with own memories)
Why are post-event discussions thought to reduce the accuracy of EWTs?
Memory conformity (EWs go along with each other to win social approval, NSI, or because they believe the others are right, ISI)
Outline Gabbert et Al’s 2003 research on PED
Aim:
- To investigate the impact of PED on EWT accuracy
Procedure:
- Lab experiment
- 120 ppts (60 students from Aberdeen Uni + 60 local adults)-volunteer
- 2 independent groups
Control condition: individuals watched + recalled crime alone (no PED)
Experimental condition: individuals paired up + watched diff perspectives of a crime (one incriminating one not), had PED, then recalled individually
Findings:
- Control group: no mistakes or wrongful convictions
- Experimental group: 71% ppts recalled things they didn’t see + 60% who saw a non-incriminating perspective wrongfully convicted them
Conclusion:
- PED causes memory contamination, affecting the accuracy of EWTs
Who did a study to investigate the impact of PED on EWT accuracy? When?
Gabbert et al (2003)
Give 2 positive evaluation points for misleading info being a factor that affects EWT accuracy
Research support
- Loftus + Palmer 1974 (leading questions)
- Gabbert et al 2003 (post-event discussion)
- Multiple studies have supported idea that misleading info reduces the accuracy of EWTs
Practical applications
- Conclusions have increased understanding of how to improve accuracy of EWTs
- Can now reduce misleading info to improve EWT accuracy + hopefully reduce wrongful convictions in the legal system
- E.g. Remove leading questions from interviews + keep EWs apart to prevent PEDs
Give 2 negative evaluation points for misleading info being a factor that affects EWT accuracy
Methodological issues with research support reduces external validity
- Loftus + Palmer and Gabbert et al used lab studies with vids of crimes
- Foster et al (1994) argued this method has low external validity, as ppts will put in less effort to accurately recall info if they don’t expect real consequences
- So, the situation has low mundane realism + may not be generalisable to real situations where EWTs are used
Samples in research studies may not have been representative
- Loftus + Palmer and Gabbert et al used independent groups design, so individual differences may have been able to confound results (e.g. differences in driving experience impacted speed recalled)
- The ppts were also both small (45 + 120) and from specific areas in Western cultures (US + Aberdeen) so population validity may have been low
What theory affecting EWT did Anastasi + Rhodes propose in 2006?
Theory of own age bias
EWs better at identifying people their own age
What is anxiety?
A state of emotional + physical arousal which may have an affect on the accuracy of EWTs
What characteristics show the emotional arousal from anxiety?
Feelings of worry + tension
What characteristics show the physical arousal from anxiety?
- Increased heart rate
- Sweatiness
Is anxiety thought to increase or decrease the accuracy of EWTs?
Unclear - inconclusive research
Why is anxiety thought by some to decrease the accuracy of EWTs?
The emotional + physical arousal from anxiety prevents us paying attention to important cues, as we focus on the source of the anxiety (TUNNEL THEORY) damaging recall/accuracy of EWT
Why is anxiety thought by some to increase the accuracy of EWTs?
Anxiety triggers a fight or flight response, increasing alertness + awareness of cues, improving recall/accuracy of EWT
Who did research to support the theory that anxiety negatively affects EWT accuracy? When?
Johnson + Scott (1976)
Outline the research by Johnson + Scott 1976 on anxiety affecting EWT
Aim:
- To investigate the affect of anxiety on EWT accuracy
Procedure:
- Lab study
- Ppts believed they were in a waiting room before starting a study
- Overheard argument in next room
- Independent groups…
Group 1 (High anxiety condition): man walked through room holding paper knife covered in blood
Group 2 (Low anxiety condition): man walked through rooms holding pen covered in grease
- Ppts later asked to identify man from 50 photos
Findings:
- Group 1 (high): less accurate (33%)
- Group 2 (low): more accurate (49%)
Conclusion:
Anxiety causes focus on source of anxiety rather than whole situation, decreasing EWT accuracy
Who did research to support the theory that anxiety positively affects EWT accuracy? When?
Yuille + Cutshall (1986)
Outline the research by Yuille + Cutshall 1986 on anxiety affecting EWT
Aim:
- To investigate the affect of anxiety on EWT accuracy
Procedure:
- Used 13 of the 21 witnesses of a real crime in a Canadian gun shop, where owner shot thief dead (high anxiety)
- Ppts interviewed to give EWT straight after + rate level of stress
- Ppts interviewed to give EWT 4-5 months later
- Accuracy of EWT compared
Findings:
- Witnesses very accurate after 4-5 months
- Most accurate accounts were from witnesses who had highest stress/anxiety (88% accurate compared to less stressed group 75%)
Conclusion:
- Anxiety increases EWT accuracy by heightening senses + awareness in preparation for a fight of flight response
Give 2 negative evaluation points for Johnson + Scott’s 1976 research on anxiety affecting EWT
Negative: Ethical issues
- Used deception (didn’t know true aim of study or that weapon was fake)
- No protection from harm
- May have found situation psychologically distressing
Negative: Alternative explanation (measuring affect of surprise on EWT, not affect of anxiety)
- Pickel (1998)
- Repeated study in salon, using 4 conditions: scissors, wallet, handgun, chicken
- Identification of man much less accurate in conditions with surprise: handgun + chicken
- Suggests surprise causes tunnel theory, not anxiety
Give 1 positive + 1 negative evaluation point for Yuille + Cutshall’s 1986 research on anxiety affecting EWT
Positive: Methodology
- Real life study (natural experiment)
- Higher external validity, so more generalisable results, as better mimics real situations
Negative: Methodology
- Lacked control of extraneous variables
- Other factors may have influenced EWT accuracy, e.g. PEDs
- Internal validity lowered, as may not be solely measuring affects of anxiety on EWT accuracy
Who created a theory to explain the contradictory findings regarding the affect of anxiety on EWT accuracy? When? What was the theory?
Yerkes + Dodson (1908)
- ‘Yerkes-Dodson Law’
- Theory that relationship between performance + arousal from anxiety is an inverted U shape
Deffenbacher (1983)
- Applied Yerkes-Dodson Law to EWT
- Theory that recall accuracy increases as anxiety increases up to an optimal point, but after this point as anxiety continues to increase the accuracy of recall decreases
Why may the inverted-U explanation be criticised?
Too simplistic - anxiety is a complex process
What is the term for when tunnel theory happens around a weapon? Does this decrease or increase EWT accuracy?
- Weapon focus effect
- Decreases EWT accuracy
