Memory Eyewitness Testimony. Learning objectives Understand what is meant by eyewitness testimony...

Memory

Eyewitness Testimony

Learning objectives

Understand what is meant by eyewitness testimony (EWT)

Be aware of some of the factors that affect the accuracy of EWT.

Understand the impact of misleading information on EWT.

Describe the cognitive interview technique and understand its rationale.

Describe and evaluate evidence that underpins our understanding of EWT.

From The TimesMay 23, 2007

201 wrongful convictions are tip of the iceberg, says DNA charity Tim Reid in Washington A man who spent 19 years in jail for the murder of two children

will be exonerated formally in July, putting the number of inmates in America cleared by DNA evidence at more than 200.

Byron Halsey, who narrowly avoided the death penalty when he was convicted in 1988 of the sexual assault and murder of a girl, 7, and a boy, 8, had his conviction thrown out by a judge last week after DNA evidence pointed to another man as the killer.

Mr Halsey’s exoneration means that since the first American inmate was cleared by DNA evidence in 1989 another 200 have now been proven to be convicted wrongfully, according to the Innocence Project, a New York legal charity that pioneered the use of DNA analysis.

Affects of misleading information

Distortion after the event Due to post-event

information Loftus (1992) called this ‘misinformation

acceptance’ More so as time goes on

after the event Important implications

for questioning suspects.

Elizabeth Loftus

Used lab experiments

Using videos of road traffic incidents

Barbara Loftus

Followed by post-event informationIncluding leading questionsTest for memory of original eventFinding – false info after the event can

change the original memory

Classic study by Loftus (1975)

Participants were shown a film

Then divided into 2 groups

Group 1 was asked questions consistent with what they had seen

Procedure

How fast was the white sports car going when it passed the Stop sign.

How fast was the white sports car going when it passed the barn while travelling along the country road?

Findings

There had been a stop sign in the film but no barn.

17% in the experimental group (the group asked the leading questions) reported seeing a barn.

Only 3% in the control group (not asked leading questions) made this error.

Conclusion

Participants who are given misleading post-event information believed they had really seen the barn.

This information had been absorbed into their original memory.

Criticisms

Is it possible that participants are responding to demand characteristics?

This would mean participants hadn’t really had their memory changed.

To test this…

Loftus offered a money rewardFor correct recollection of details from a

film of an accident.One group saw a film involving a

pedestrian being knocked over after a car stopped at a Stop sign.

The other group saw the same incident except the car stopped at a Yield sign (American equivalent of Give Way).

Two days later Participants were given a set of questions

about the incident. One question was misleading. Participants who saw the Stop sign were

asked about a Yield sign. Participants who saw the Yield sign were

asked about a Stop sign. Loftus showed pairs of slides, one with a Yield

and one with a Stop.

Participants were divided as follows:1 offered no monetary rewardOffered $1 for each correct answerOffered $5 for each correct answer$25 offered for person in the group who

scored the most correct answersNEED FOR CORRECT ANSWERS

WAS EMPHASISED BY LOFTUS

Findings

In spite of financial incentives Over 70% made an error on the crucial

question in line with the misleading info they received.

This suggestsThat the original memory had been

altered as a result of the misleading post-event information.

Divide class into 2 groups:A and BGroup B should close their eyes when

Group A are doing the task and vice versa

Group B – write your answers down

Did you see a broken headlight in the clip you saw earlier?

How fast do you think the bike was going when it made contact with the car?

Group A – write your answers down

Did you see the broken headlight in the clip you saw earlier?

How fast do you think the bike was going when it smashed into the car?

findings

Are our findings the same as Loftus and Zanni (1975)?

They found17% of those with the leading question

reported seeing it7% of those asked about ‘a’ broken

headlight reported seeing it.

findings

The verbs, ‘smashed’, ‘bumped’, ‘collided’, or ‘contacted’

Had a significant effect on the estimates of speed.

A week later, those who had been given the word ‘smashed’ were more likely to report seeing broken glass even though there had been none.

Other factors affecting EWT

Information may not be registered in the first place.

In real life situations, accidents happen suddenly and people aren’t expecting something to happen.

Memories are reconstructed with preconceptions.

We fill in gaps with our own knowledge and experience of the world (schemas).

Schema for a bank robbery

Write a list of things that immediately comes to mind when thinking of a bank robbery.

Male Disguise Dark clothes Getaway car outside Driver in the car waiting According to Tuckey and Brewer (2003)

Interference with memory

Palace or museum

Lindsay et al. (2004)

Participants told about a

Burglary at a palace Or a school trip to a

palace

Interference when things are similar

When shown a video of a burglary at a museum who would make more errors on recall of details?

Those who had heard about palace burglary previously rather than a school trip.

Why?

Other factors that affect EWT

Anxiety

http://www.onlineclassroom.tv/psychology/catalogue/psychology_critical_issues/eyewitness_testimony