Y2: Psychology: Criminal: Classic Study: Loftus and Palmer

• To investigate the accuracy we remember the detail of a complex event, like a traffic accident

• To test the hypothesis that the language used in eye witness testimonies can alter memory, specifically the role of leading questions

45 American students

Lab

• 45 American students were split into 5 groups

• They were shown 7 clips of 5-30 seconds each of a staged traffic accident that were taken from the Evergreen Safety Council and Seattle Police

• After watching the clips the ppts received a questionnaire asking them to give an account of the accident as if they were an eye witness

• They were then asked the critical question of: “About how fast were the cars going when they hit each other?”

• The verb hit would be swapped with smashed, collided, bumped, or contacted depending on the condition the experimental group were in

• The clips were counterbalanced as the order was different for each group

IV = the verb used in the critical question (smashed, collided, bumped, hit, contacted)

DV = the estimated speed of the car in mph

Smashed - 40.5 mph

Collided - 39.3 mph

Bumped - 38.1 mph

Hit - 34.0 mph

Contacted - 31.8 mph

• The verb used in the critical question influenced the speed estimate

• The more powerful verbs that suggested higher speeds before impact received higher estimates

1) Distortion - the verbal label attached to the event could have led to the ppt cognitively changing their memory through re-evaluation of what they already know
2) Response bias - a type of demand characteristic whereby the ppt is not sure of the exact speed and therefore adjusts their estimates to fit in with the expectations of the questions

• To investigate the origin of the different speed estimates

- To investigate whether estimates were due to demand characteristics of response bias or memory alteration

150 students

Lab

• 150 students were split into 3 equal groups

• They were shown a 1 min film of a multiple car accident that lasted 4 seconds

• At the end they were given a questionnaire asking them to describe the accident and then answer 10 questions about it that were asked in a random order

• They were asked the critical question of: “About how fast were the cars going when they hit each other?”

• The verb was changed to smashed or hit, for two conditions, the third were not asked for a speed estimate

• 1 week later the ppts returned and were asked: “Did you see any broken glass?” even though there wasn’t any

IV = whether they were asked if the car smashed, hit, or weren't asked at all

DV = the speed estimate and whether or not they answered yes/no to there being any broken glass

Smashed - 16 said YES, 34 said NO
Hit - 7 said YES, 43 said NO
Control - 6 said YES, 44 said NO

Yes because those who estimated speed in smashed condition averaged 10.46 mph whereas those in hit averaged 8 mph which is significant due to t(98) and having a difference of 2 at p<0.05.

• The smashed condition had the highest amount of people responding yes and lowest amount responding no

• This suggests that people in the smashed condition assumed there would be broken glass if they could not recall any themselves

P - Low
E - Sample of 45 American students in first study who were around the same age
E - This an ethnocentric and age- locked sample which is therefore not representative of wider population such as middle aged people who live in other parts of the world

P - High
E - Standardised procedure of showing 7 5-30 second films of a staged car accident
E - Easy to replicate and test for consitency
P - High
E - Data gathered was quantitative and measurable due to an estimate of car speed in mph
E - Easy to compare if study was repeated

P - Yes
E - Found that smashed resulted in an estimate of 40mph whereas hit was 34mph in first study, showing how leading questions can alter memory if something is suggested even if it didn’t happen
E - Therefore should advise police for interviewing witnesses to avoid asking questions about things the witness hasn’t mentioned so that their testimony is more accurate

P - Low ecological
E - Ppts watched 7 5-30 second films of a staged car accident
E - This does not represent a real life event as attention and emotional engagement of the witness would be different due to not already focusing on where the event would take place
P - Low
E - 45 American students used in the sample were psychology students participating in lab based research that they would be familiar with and so would guess the aims
E - Therefore they may show DCs which would not accurately reflect real life EWTs

P - Good
E - The 7 5-30 second films were of staged accidents
E - Therefore this would be less distressing for the ppts and so they would be protected from psychological harm
P - Bad
E - There were elements of deception due to the leading questions
E - Therefore ppts were lied to