# Loftus and Palmer

• Loftus and Palmer
• Background
• Research has shown memories can be inaccurate. this is a problem for eye witness testimony
• James Marshal 1969 found air force personel when asked to estimate the speed of a car going 12mph estimates ranged from 10-50mph
• First experiment
• Aim
• If estimates of speed would be influenced by wording of Question asked
• Method
• Design- Lab experiment Independent measures Snapshot study
• IV - The verb given to PP's  DV - The PP's estimate of speed
• Sample
• 45 American college students. Divided into 5 groups one for each verb
• Materials and apparatus
• Pps shown 7 film clips and asked to fill in a questionaire after each clip
• Clips were from a driver education program for evergreen safety council and Seattle police department
• Procedure
• PP's were asked to describe accidents and to estimate the speed of the car
• Each group had different verb in the question on questionnaire Hit , Bumped, collided, smashed contacted
• Different order of film clip were used for each group
• Two Explanations
• Response bias, verb smashed makes the accident sound high impact leading to a higher speed estimate
• Memory representation the verb changes the  perception of the accident this is stored with the memory
• Results
• Mean estimate was faster for PP's with Smashed than Contacted
• PP's were not able to accurately estimate speed, crashes were at 20,30,40 mph yet estimates were between 36-40
• Discussion
• Form of a question can have an effect on the answer to a question
• Second Experiment
• Aim
• If a leading question would change recollection of event
• Method
• Design - Lab experiment, independent measures         IV - verb in critical Q DV- the estimate of speed of car Longitudinal study
• Sample - new group of 150 American students
• Procedure
• Part one
• PP's asked to describe the crash with the critical question "How fast were the cars going when they *VERB* into each other?"
• Group one had verb - Smashed Group two had verb Hit Group three was control and wasn't asked question
• Part two
• A week later Pp's were asked if they saw any broken glass ( there was no broken glass)
• It was presumed those that though the cars were traveling faster, may have thought they saw broken glass
• Results
• Part One
• PP's in smashed condition gave a higher speed estimate smashed - 10.46 mph  Hit - 8 mph
• Part Two
• PP's in smashed condition though they saw broken glass more than hit condition or control
• Did you see broken glass? Smashed - Yes 16  No 34 Hit- Yes 7 No 43 Control - Yes 6 No 44
• Discussion
• Memory is determined by two sources 1) - Your own perception learned at the time of original event 2) External information supplies after eg leading question.