Memory L7 - Accuracy Of Eye-Witness Testimony: Misleading Information

Question 1

What’s Eye-Witness Testimony?

Answer 1

• this refers to an account given by people of an event they have witnessed
  Definition: the ability of people to remember the detail of events, such as accidents and crimes, which they themselves have observed.

Question 2

What affects EWT

Answer 2

suggested accuracy can be effected by misleading information such as leading questions and post event discussions

Question 3

What’s misleading information

Answer 3

• seen as incorrect information given to the eyewitness usually after the event (hence often called ‘post event discussion’).
• It can take many forms, such as leading questions and post-event discussion between co-witnesses and/or other people.

Question 4

Leading questions

Answer 4

a question that suggests to the witness what answer is desired, or leads him/her to give a certain answer because of the way it was phrased

Question 5

Studies to support leading questions

Answer 5

Loftus and Palmer (1974) (1)
Loftus and Palmer (1974) (2)
Loftus and Zanni (1975)

Question 6

Loftus and Palmer (1974) (1)

Answer 6

• 45 students were shown a video of car accident - then asked about the speed of the car on impact
• One group of participants asked, ‘how fast were the cars going when they hit each other?’
• Other participants were asked the same question but the verb ‘hit’ was replaced with either ‘smashed’, ‘bumped’, ‘collided’ or ‘contacted’.

Results:The verb used had a significant effect on the estimated speed. The verb ‘contacted’ lead to the lowest estimated speed (a mean of 31.8 mph) and ‘smashed’ the highest (a mean of 40.5 mph)

Conclusion: Some of the verbs used in the experimenter’s questions were leading, encouraging participants to believe that cars were going faster (in the case of smashed) or slower (in the case of contacted) than they really were.

Question 7

Loftus and Palmer (1974) (2)

Answer 7

• Shocked by findings of first experiment so they conducted a second experiment to see if the wording of a leading question actually changes the participants’ memory of the film clip
• This was demonstrated because participants who originally heard ‘smashed’ later were more likely to report seeing broken glass (there was none) than those who heard the verb ‘hit’
• The critical verb altered their memories of the discussion.

Question 8

Loftus and Zanni (1975)

Answer 8

• Participants shown video of car accident and then asked questions
• When they were asked if that had seen ‘a’ broken headlight, 7% of participants said yes
• 17% of participants said yes if they were asked if they had seen ‘the’ broken headlight, even though there was no broken headlight
  Conclusion: The word ‘the’ was leading as it implied there was a broken headlight - this leading question affected participants’ memory

Question 9

Post-event discussion

Answer 9

Post event discussion involves when witnesses to an event discuss what they have experienced after the event.

This is argued to affect accuracy of EWT due to:
1) Memory contamination: Witnesses mix information from other witnesses into their own memories
2) Memory conformity: Witnesses pick up details from the eye witness testimony of other witnesses because they want social approval (NSI) or because they believe other witnesses are right (ISI), and they are wrong.

Question 10

Post-event discussion research

Answer 10

Gabbert et al. (2003)

Question 11

Gabbert et al. (2003) aim and method

Answer 11

Aim: To investigate the effect of post‐event discussion on the accuracy of eyewitness testimony.
Method:The sample comprised 60 students from the University of Aberdeen and 60 older adults recruited from a local community.
- Participants watched a video of a girl stealing money from a wallet.
- The participants were either tested individually (control group) or in pairs (co‐witness group).
- The participants in the co‐witness group were told that they had watched the same video; however, they had in fact seen different perspectives of the same crime and only one person had actually witnessed the girl stealing.
- Participants in the co‐witness group discussed the crime together.
- All of the participants then completed a questionnaire, testing their memory of the event.

Question 12

Gabbert et al. (2003) results and conclusion

Answer 12

Results: 71% of the witnesses in the co‐witness group recalled information they had not actually seen (compared to 0% in the control group) and 60% said that the girl was guilty, despite the fact that they had not seen her commit a crime.
Conclusion: These results highlight the issue of post‐event discussion and the powerful effect this can have on the accuracy of eyewitness testimony
- Thus, witnesses will absorb information from other witnesses, either because of memory contamination or memory conformity.

Question 13

Evaluation of research into the effects of misleading information (leading Q’s & post-event discussion) on EWT

Answer 13

strengths
- mostly well-controlled lab studies
- important applications to real life
weaknesses
- lack validity
- population validity

Question 14

Mostly well-controlled lab studies

Answer 14

• One strength of research into the effects of misleading information on EWT is that they were mostly well-controlled lab studies.
• Extraneous variables are easy to control making it easier to make a conclusion about the effect of misleading information.
• Also, studies can be easily replicated to test reliability.
• e.g. both Loftus and Palmer’s study and Loftus and Zanni’s study were carried out under controlled condition where all participants experienced exactly the same standardized procedure – e.g. the verbs used (hit, smashed etc.) - this could be repeated as many times as needed with different participants over time.

Question 15

Real-life application

Answer 15

• Research into misleading information on the accuracy of ETW has important applications to real life
• Because leading questions can affect witnesses memory, this shows that the police must be very careful in how they phrase questions when interviewing witnesses.
• Research also suggests that where possible, co-witnesses should be prevented from discussing their testimony – this was shown in Gabbert’s study whereby pps who had discussed the film clip with fellow pps were more likely to include information that was not even in the film clip than the control group who had not discussed the film clip with anyone.
• Research of this nature therefore shows the dangers of post-event discussion and has had a real impact on the legal system and in improving the accuracy of EWT.

Question 16

Lack validity

Answer 16

• Normally watching a video of an event such as the car accident in Loftus’ study is very different to watching a real event in real time.
• Watching a staged event on a video does not cause any anxiety. Studies have shown small amount of anxiety increase accuracy.
• In real life EWT may have serious consequences. This is not true in a research study and so participants are less motivated to be accurate.
• All these factors make memory recall in a lab very different to EWT in real life, and therefore challenges the validity of EWT research. In real life memory recall may be more accurate and less affected by misleading information.
• In lab studies into EWT there is risk of demand characteristics- participants may guess the aim of the experiment and give answers they feel the experimenter wants to hear. Again this effects the validity of EWT research as participants may be giving answers which don’t reflect their true memories.

Question 17

Study that shows the impact of real life incidents and accuracy of EWT

Answer 17

Yuille and Cutshall (1986)
– this was an ecologically valid study because it was a real life incident.

Question 18

Yuille and Cutshall (1986)

Answer 18

• In this study 13 witnesses of a real crime (an armed robbery) were interviewed 5 months after event. - Whilst being interviewed, participants were also asked two leading questions to see if this would affect their accuracy.
• Recall was found to be accurate, and two leading questions had no effect on recall accuracy.

Conclusion: This suggests that EWT is more accurate and less affected by leading questions in real life. Again this suggests that studying EWT in a lab may not be a valid way of investigating EWT in real life.

Question 19

Population validity

Answer 19

A final weakness of research studying the effects of misleading information particularly leading questions on the accuracy of EWTs was that many of Loftus’ key experiments involved student participants.
- This is not a representative group (students may have better memories for example) so we cannot generalize the findings.
- We can therefore say that the sample has low population validity.