Transcript Lesson 8 – Factors affecting eyewitness testimony

RECAP
1. what’s the difference between
state-dependent forgetting and
context dependent forgetting?
2. Outline the research to support
context-dependent forgetting
3. Outline the research to support
state-dependent forgetting
Factors
affecting
Eyewitness
Testimony
•
Objectives:
To be able to outline
factors affecting
eyewitness testimony
including leading
questions
Key Word
• Eyewitness Testimony
The testimony, based on
memory, of an individual
who saw an incident take
place.
EWT is important because…
Starter
• Can your memories be changed?
• https://www.youtube.com/watch?v=il0u
2s_WGXA
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Item list
□Refrigerator
□Oven
□Cabinets
□Dish rack
□Toaster
□Microwave
□ Toaster oven
□ Coffee maker
□ Rice cooker
□ Cereal box
□ Pot
□ Pan
□ Sink
□ Kitchen magnet
□ Salt and pepper
shaker
□ Can opener
□ Paper towel holder
□ Cup
□ Plate
□ Dish towel
□ Spoon
□ Fork
□ Bowl
□ Washing up liquid
□ Fruit
□ Picture frame
□ Water bottle
□ Oven mitt
□ Plant
□ Watch
□ Knife set/block
□ Fan
□ Fire extinguisher
□ Purse
□ Clock
□ Hawaiian garland
□ Pom pom
□ Television
□ Pill bottle
□ Cell phone
□ Hammer
□ Shoes
□ Perfume
□ Mr. Potato Head
□ Book
□ Baseball glove/mitt
□ Iron
□ Deodorant
Who would you most trust to
have given a good account?
Anxiety
Schemas
(previous
experiences)
Which factors effect EWT?
Leading
Questions/
Misinformation
Consequentiality
(thinking you’re
responsible)
Key Terms
Misleading information: incorrect information given to the
eye witness usually after the event (post-event information).
This can be leading questions or post-event discussion
between other witnesses and people.
Leading question: a question which, because of the way it
was phrased, suggests a certain answer. “was the knife in the
accused’s left hand?” this suggests that the answer is left
hand.
Post-event discussion (PED): occurs when there is more
than one witness to an event. Witnesses may discuss what
they have seen with co-witnesses or with other people. This
may influence the accuracy of each witness’s recall of the
event.
Car Crash Video
http://www.youtube.com/
watch?v=Rg5bBJQOL74
Watch the video and
answer the questions on
your sheet.
Loftus and Palmer
An investigation into
leading questions. Notice
that there were different
sheets, one said ‘bumped’
the other said ‘smashed’ –
what did our experiment
show?
What is a leading question?
Key Word
• Leading question
A question phrased in such
a way as to prompt a
particular answer.
For example “What colour
was the man’s hat?” rather
than, “Was the man
wearing a hat?”
Research into Leading Questions
• Loftus and Palmer (1974)
• Loftus (1975)
Loftus and Palmer (1974)
Reconstruction of
Automobile Destruction
Aim
To investigate how information
provided to a witness after an
event will influence their
memory of that event
Method – Experiment
1
• 45 student participants were shown short video clips
• They were split into 5 groups, with 9 participants in each one
• All of the participants were asked:
‘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
Results – Experiment 1
VERB
MEAN
ESTIMATE OF
SPEED (mph)
Smashed
40.8
Collided
39.3
Bumped
38.1
Hit
34.0
Contacted
31.8
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.
Method – 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).
• One group was asked:
‘How fast were the cars going when they hit each other?’
• The second was asked:
‘How fast were the cars going when they smashed into each other?’
• 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?’
There was no broken glass in the film.
Results – Experiment 2
Did you see any broken glass?
Response
Yes
No
Smashed
16
34
Hit
7
43
Control
6
44
What do these results show?
The results show that the verb used in the original question
influenced whether the participants thought they had seen
broken glass.
Why do leading questions affect
EWT?
• Response-bias explanation suggests the wording
of the question has no real effect on the
participants memory as such, but influences
how they decide to answer e.g the word
‘smashed’ encourages participants to increase
the speed estimate
• substitution explanation – the wording of a
leading question actually changes the
participants memory of the film clip.
Participants who heard ‘smashed’ were more
likely to report a broken headlight (there
wasn’t actually a broken headlight) later on than
those who heard ‘hit’.
Evaluation
• Discuss the evaluation of Loftus &
Palmer
• Can you think of any strengths?
• Are there any limitations?
• Complete your booklet using page 59
Post-event discussion
• When co-witnesses to a crime discuss it
with each other (post-event discussion),
their eye-witness testimonies become
contaminated.
• This is because they combine
(mis)information from other witnesses
with their own memories. Research to
support…
Read page 28 of your booklet and highlight
key points.
Supporting evidence – A03
P: there is further evidence supporting the
fact that leading questions can distort EWT
EE: Loftus (1975) found that 17% percent of
participants who watched a video of a car
ride and were asked ‘how fast was the car
going when it passed the white barn’ recalled
seeing a barn a week later
L: this supports the idea that post-event
information added to a memory after the
event has occurred, can affect recall.
Test Yourself…
1. Which of the following was not a cue word in the experiment by
Loftus and Palmer?
a) Smashed
b) Contacted
c) Knocked
d) Hit
The correct answer is… c) Knocked
Test Yourself…
2. The DV in the first experiment was…
a)
Estimate of speed
b) The verb ‘smashed’
c)
The question about broken glass
d) The film
The correct answer is… a) Estimate of Speed
Test Yourself…
3. In Experiment 1, how many experimental conditions were
there?
a)
1
b) 3
c)
5
d) 7
The correct answer is… c) 5
Test Yourself…
4. In Experiment 2, how many experimental groups were
there?
a)
1
b) 2
c)
3
d) 4
The correct answer is… b) 2
Test Yourself…
5. In Experiment 2, participants were tested immediately and then asked
to return for some more questions. How long afterwards was this?
a)
1 day
b) 3 days
c)
1 week
d) 2 weeks
The correct answer is… c) 1 week
Test Yourself…
6. In Experiment 2, which group saw the most broken
glass?
a)
The ‘smashed’ group
b) The ‘collided’ group
c) The ‘hit’ group
d) The control group
The correct answer is… a) The
‘smashed’ group
Test Yourself…
7. Which of the following is true?
a)
Experiment 1 and 2 were both repeated measures
b) Experiment 1 and 2 were both independent measures
c)
Only Experiment 1 was repeated measures
d) Only experiment 1 was independent measures
The correct answer is…
Experiment 1 and 2 were both
independent measures
b)
Test Yourself…
8. The participants in this study were:
a)
Children
b) Students
c)
Teachers
d) Adults
The correct answer is…
Students
b)
Exam Question
“Outline and evaluate research
into the effects of leading
questions on eyewitness
testimony (12)”