Eyewitness TestimonyElizabeth Loftus

Aims/Objectives:

Aim: To start looking at memory in everyday life:Objectives:•To be able to understand the basis of EWT (Eyewitness Testimony).•To begin to understand the various stages of EWT•To begin looking at factors that effect EWT

Task:

•Fill in the handouts. You have 5 minutes to do this.

Answers to tasks:VISUO-SPATIAL SKETCHPAD

HOLDS VISUAL MEMORIESEG: FACES

EPISODIC BUFFER ADDED IN 2000 (BADDELEY)INTEGRATES INFORMATION from the central executive, the visuo-spatial sketchpad and phonological loopLIMITED CAPACITY

CENTRAL EXECUTIVE

MODALITY -FREE.ROUGHLY THE SAME AS ATTENTIONALLOCATES RESOURCES TO OTHER COMPONENTS

Application of memoryApplication of memory

Memory research has valuable application•Can you think of some examples?

•One relevance to real / day to day life is eyewitness testimony (EWT)

How good is memory?

• You may be surprised how difficult it is to remember what a 10p looks like without having one in front of you

• There will be a number of inaccuracies

• We do not need to have 100% recall for all information we use everyday. For example we only need to know the shape of coins and notes to be able to use them correctly.

In pairs and without looking anything up, try to do the following 2 tasks.

1.Draw a picture of a 10p coin, front and back.2.Write down the person on the front of a £5 note. Write down the words written at the top of the front of the note of any denomination (i.e. £5, £10, £20, £50).

TASK: pg 48 in your packs…

• Watch the clip carefully

• Half way through I will stop the video and you must write down all the changes you saw in the clip. Over all there are 21. You have 3 minutes!

• Test Your Awareness : Whodunnit? - YouTube

SchemasSchemas• Knowledge packages built up through our experience of

the world. They also help us to interpret new experiences.

• For example-knowing that there will be tables and chairs in a restaurant. This would be your restaurant schema.

• They help to fill in gaps in knowledge we have. • However they can lead to distortions when new

information doesn’t fit properly into our existing knowledge.

• Cultural experiences and stereotypes affect memory.• These distortions are particularly interesting when we

look at EWT.

Research findings on the role of Research findings on the role of schemas:schemas:

• Brewer and Treyens (1981) looked at the effects of schemas on visual memory. • They asked 30 p’s, one at a time, to wait in a

room that had been set up to look like an office for 35 seconds.

• In the room there were objects such as a desk, chair, calendar and typewriter

• These objects were compatible with an office schema

• However there were a few items that were non-compatible, such as a skull, a pair of pliers and a brick.

Continued:Continued:

In an unexpected recall task the following results were found:•P’s recalled the obvious office items that fitted with schema expectancy, but were less successful at recalling the strange items

•8 p’s, however, recalled the really bizarre item-the skull8 p’s, however, recalled the really bizarre item-the skull

•Most errors in recall were substitutionssubstitutions. • For example p’s would add in items that weren’t there such as pens,

books, and a telephone, which would have a high schema expectancy but weren’t there on this occasion.

1. Why do you think that some p’s recalled seeing a skull in the office (Brewer and Treyens, 1981)?

You have 3 minutes to answer the question. Prepare to feedback.

TASK…

EWT Stages:EWT Stages:

1. The witness encodes info into LTM (the event and the person involved)

may be partial as the event occurs quickly, at night and accompanied by rapid, violent, complex action

2. Witness retains info for a time. Memories may be lost or modified during retention, other activities may interfere with the memory itself

3. Witness retrieves memory from storage. What happens next is there may be a presence or absence of info that may affect the accuracy of the memory.

Factors affecting EWT:Factors affecting EWT:

The main factors affecting accuracy of memory can be placed into two categories:

1.1.Witness factorsWitness factors: age, race, gender and individual response to anxiety or stress.

2.2.Event factorsEvent factors: duration of event and level of violence witnessed.

We will be looking at age, anxiety and the effect of misleading information.

• Turning to the person next to you, identify at least 5 factors that you think could affect an eyewitness’s account

• Consider why and how these factors could affect• You have 5mins – be prepared to feed back to the class

Misleading Information 1 - Leading Questions 1 - Leading Questions

2 - Post Event Information 2 - Post Event Information

LoftusLoftus

Factors affecting eyewitness testimony:•Elizabeth Loftus is a psychologist who argues that eyewitness testimony in court is very unreliable.unreliable.•She looked at:

• whether people reconstruct memory, • whether the memory persists (stays) or • whether they can be ‘led’ in to answering in a certain way.

Loftus and Leading Questions

How does information presented after an event

affect a witness’s memory for that event?

PProcedure

Experiment 145 participants took part. •They all saw a video of a traffic accident.•After the video they were all asked the same questions about the accident. •Apart from 1 question which was about the speed the cars were going

‘About how fast were the cars going when they ________ each other’

Each group was given a different verb to fill in the blank. These verbs were ‘smashed, collided, bumped, hit or contacted’.

Therefore the independent variable was the verb used.

The dependent variable was the estimate of speed given by the participants

RResults

Experiment 1

VerbVerb Mean Speed Mean Speed EstimatesEstimates

Smashed Smashed 40.840.8

CollidedCollided 39.339.3

BumpedBumped 38.138.1

HitHit 34.034.0

ContactedContacted 31.831.8

What do these results show?

• How the question was phrased influenced the participants’ speed estimates

• When the verb ‘smashed’ was used, participants estimated that the cars were travelling much faster than when the verb ‘contacted’ was used.

CConclusion

We can conclude that people’s memory for an event can be influenced by the questions they are asked about it and those questions can distort (change) our long term memory for an event

We don’t know whether the reported speed was due to a genuine change in the participant’s memory, or through demand characteristics (participants guessing the true nature of the experiment)

Experiment 2

150 student participants were shown a short film that showed a multi-vehicle car accident and then they were asked questions about it.

The participants were split into 3 groups (with 50 in each group)

1. One group was asked:

‘How fast were the cars going when they hit each other?’

2. The second was asked:

‘How fast were the cars going when they smashed into each other?’

3. The third group was not asked about the speed of the vehicles

One week later, all participants returned and were asked:

‘‘Did you see any broken glass?’Did you see any broken glass?’

There was no broken glass in the film.

PProcedure

Response Smashed Hit Control

Yes 16 7 6

No 34 43 44

Did you see any broken glass?

The results show that the verb used in the original question influenced whether the participants thought they had seen broken glass.

RResults

Experiment 2

What do these results show?

CConclusion

There seems to be evidence that suggests post event misleading questions can have an adverse effect on EWT.

Task: using your text books and this PP complete pgs50-54 in your packs.

• Do you think that demand characteristics may have affected the results of Loftus and Palmers study? Explain your answer.

• What extraneous variables could have effected the results of the study?

• What method was used? And how might that have effected the results?

Work in pairs to answer the questions. You have 5 minutes.

Research methods check:

Now, complete a GRAVE!

Questions to consider:Questions to consider:

•How useful was the research?

(How can the results of the study be Applied to other situations?)

•How realistic were the studies?

(Think about the differences between the tasks the participants did, and real life situations where you need to remember what you have seen)

•Who were the participants?

(Could the results be Generalised to other people?)

•Any other issues

(Think about the type of tasks, the content of the video, etc)

•What differences would there be in ‘real life situations?’•How easy is it to estimate speed?

•What if the car had been a Porsche or a Smart Car?

•Was the memory really changed?

2 - Post event Discussion / Information

If you witness a crime and then discuss it with another person, what could happen?

CONTAMINATION!!!

GABBERT (2003)PP - Pairs of p’s watched a video of the same crime but filmed from different viewpoints•Each P therefore had different elements of the event•Both p’s then discussed with their partner before individually answering questions

RR - 71% p’s mistakenly recalled aspects of the event that they did not see •They had picked this info up through discussion•Control group – no discussion – 0%

CC - Witnesses go along with each otherWhy??!! Is there any other explanation we have looked at that could explain this?

SOCIAL APPROVAL?

THEY BELIEVE THE OTHER PERSON IS

CORRECT – ISI???

MEMORY CONFORMITY!!

Complete pg 55 in your pack

Ticket to leave….

• One thing I have learned….• One question I still have….

Question 1

What are the two types of cue in the cue-dependent theory of forgetting?

Question 2

Name two psychologists who have studied memory and say which theory/topic it relates to.

Question 3

Give one fact about the participants in Loftus and Palmer’s study.

Question 4

Explain in your own words, what a memory trace is.

Question 6

Give two features about the short-term memory store.

Question 7

Name three of the verbs used in Loftus and Palmer’s study.