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Loftus and Palmer - Eye Witness Testimony
Transcript of Loftus and Palmer - Eye Witness Testimony
What is Cognition?
Cognition refers to several different mental processes we have.
It isn't easy to study these processes because they are not directly observable.
Everything we see and hear is interpreted by our minds and thoughts.
Things can appear different for different people.
Newborn babies don't see objects. They just see an array of colours changing in front of them.
How do we perceive things differently?
How much can you remember?
Memory is the ability to store and recall information.
There are 3 major types of memory:
Long Term Memory
2. Short Term Memory
Years, Hours, Weeks.
What happened on your first day of primary school?
What is your first memory?
Memory that you hold onto for 15-30 seconds.
How many can you remember?
Is this easier?
Moving memories from STM (short term memory) to LTM is usually done through the process of rehearsal.
This process is known as chunking.
Count backwards from 200
Can we rely on our memories?
Sometimes our memories cannot be trusted.
In what situation would a false memory cause serious problems?
Eye witness testimony
3. Sensory Memory
A very brief (less than a second) period of memory that your senses use.
For example when looking around, your eyes keep a sensory memory of what is in your immediate surroundings.
Your eyes don't actually see that much but you think you see more than you do because of sensory memory.
Reconstruction of automobile destruction: an example of the interaction between language and memory.
Sample (experiment 2)
To Investigate the effect of Language (leading questions) on Memory.
Who questions who in a courtroom?
To see if estimates given by participants about the speed of vehicles in a traffic accident would be influenced by the wording of the question asked.
45 American Students
Split into 5 groups of 9
The participants were shown 7 video clips taken from a Seattle police road safety video.
4 of them contained a crash.
Participants were asked to recount what they had seen and then fill out a questionnaire about what they saw in the crash.
The questions in the questionnaire were identical except for one question (the critical question)
5 different "Critical Questions" were asked to 5 different groups.
Group 1 were asked:
"About how fast were the cars going when they HIT each other?"
Group 2 were asked:
"...how fast were the cars going when they SMASHED each other?"
But the 5 different verbs used for the 5 different groups were:
The Critical Question was always
"About how fast were the cars going when they _____ each other?"
The participants' answer to this question (the speed estimate) was the data collected for this study.
There was a clear indication that the severity of the verb used caused participants to give an higher estimate of speed.
Leading questions can affect the accuracy of a memory.
Loftus and Palmer gave two reasons for this:
1. RESPONSE BIAS
Participants respond to the situation. The critical word influences a persons' perspective and they follow along (similar to demand characteristics)
2. MEMORY ALTERED
The language has actually caused the memory of the participant to change. They believe the accident was more severe than it really was.
Wanting to see which explanation was the real one, Loftus and Palmer conducted a second experiment.
To investigate whether participants were estimating higher speeds from the response set or a genuine memory change.
Would participants who were in the "smashed group" be more likely to say they saw broken glass when there was none?
(3 Groups of 50)
All participants watch a 1 minute video clip that had a multiple car crash.
This time there was 3 groups:
"How fast were the cars going when they HIT each other?"
"How fast were the cars going when they SMASHED each other?"
NOT asked this question.
Second CRITICAL QUESTION.
ALL groups were asked:
"Did you see the broken glass?"
There was no broken glass in the clip.
Afterwards, the 2 experimental groups of participants were asked the critical question within a questionnaire.
Participants in the SMASHED group predicted the speed was 10.46mph
Participants in the HIT group predicted the speed was 8.00mph
16 said they saw the broken glass.
34 said they didn't.
7 said they saw the broken glass.
43 said they didn't.
6 said they saw the broken glass.
44 said they didn't.
A week later, they came back to the lab to answer a second questionnaire. In it was another critical question.
Leading questions were again influencing participants' testimony. The SMASHED group predicted speed significantly higher than the HIT group.
Participants in the SMASHED group were much more likely to say they saw broken glass than the HIT or CONTROL groups.
This could mean that participants are not showing a response set but have really altered their memory.
Loftus and Palmer conclude our memory is
1. Our own perception of the original event.
2. External information supplied afterwards (in this case, through the question).
Over time these elements merge together into one memory and we can't tell which is which anymore.
What does this mean for court cases or police interviews?
Questions must be worded very carefully to avoid witnesses creating false memories that are not accurate.
Estimate of Speed/ Whether they said they saw the broken glass.
Manipulation of word used.
Same videos used for each participant.
Same questions asked.
Standard critical question.
All of the above.
Participants answered some questions immediately and then returned a week later.
What controls were in place?
- Only American students used, similar background and culture. Not generalisable to other places, ages and countries.
+ Large sample makes it more reliable.
Generally very low.
Lab Experiment - Artificial Environment.
Artificial Task used - watching crashes and answering questions not an usual task.
Film clips are not "real life", participants don't see the consequences of the crash.
Participants were told it was an experiment on memory when it was really a experiment how leading questions effect memory.
Possibly being upset at the crashes.
+ well controlled means it is a "fair" test
+ Critical question hidden amoungst filler questions
_ Wrong estimates due to student particpants/ inexperienced drivers?
- Study did not totally resemble a real eye witness testimony (video clips)
+ Standardised test is easy to repeat
+ Study repeated in experiment 2
+ Consistent findings in a large sample
- Groups in experiment 1 could be larger
How can you find out what someone is thinking?
Write down as many words as you can
Did you get the word "Sweet"?
Did you get the word "anger"?
"Bumped doesn't sound very fast so I better predict a lower speed"
"I think the car genuinely was traveling at that speed"
We use 2 elements to reconstruct a memory
Not all psychologists agree on
people think and behave in certain ways.
Worth 50% of your final grade
Assessed by a 1.5 hour exam in May
There are 5 major areas of psychology that we will study this year.
The cognitive area
The developmental area
The individual differences area
The social area
The biological area
The kind of memory you use in quick memory tests
Write down factors that might affect how good your memory is
The cognitive area studies internal mental processes which can have an effect human behaviour.
This is a weakness of the cognitive area
When we remember events we reconstruct the event in our head.
The reconstruction is made up of:
1. What we can actually recall
2. What others have told us
Watch this clip and answer the questions on your questionnaire
Generally speaking participants were not good at estimating speeds
Actual speed of car in clip
Participants were shown 4 clips of crashes
Average speed estimated
what were the 5 verbs used?
What can we say about the participants speed estimates?
1. Participants are generally not good at estimating speed
2. The wording of the question impacts the participants speed estimates
A short memory test
How does Loftus and Palmer link to the Cognitive area?
It studies memory which is a cognitive process.
How does it link to the key theme of memory?
The aim of the study was to invesitgate if leading questions affect memory.
Which debates does Loftus and Palmer relate to?
Psychology as a science
How does this study meet the requirements of being a science?
What have we learned about leading questions?
WHO is this useful to?