loftus and palmer: eyewitness testimony

experiment 1: procedures

• 45 university students split into 5 groups

• all groups were shown the same short driver’s safety video from the Seattle police department

• all participants completed a short questionnaire that included a critical question

• ‘about how fast were the cars going when they ___ each other’

what were the different verbs used in the critical question?

• smashed

• collided

• bumped

• contacted

• hit

experiment 1: methodology

• lab experiment

• independent groups

• IV - verb used in critical question

• DV (1) - estimation of car speed

• DV (2) - answer to ‘and did you see any broken glass’

• sample (1) - 45 students

• sample (2) - 150 students

experiment 1: findings

• smashed: 40.8

• collided: 39.3

• bumped: 38.1

• hit: 34.0

• contacted: 31.8

experiment 1 conclusion: response bias

the different speed estimates occurred because the critical word influenced the participants response

experiment 1 conclusion: memory altered

results are due to the critical verb distorting the participants memory so they actually perceive, the accident differently

experiment 2: procedures

• 150 university students split into groups of 50

• shown a video of multi-car accident

• asked a series of questions, including critical question

• group 1 - ‘smashed’

• group 2 - ‘hit’

• group 3 - control group, not asked about speed of the vehicles

experiment 2: findings

experiment 2 conclusion: leading questions

the severity of the verb altered the perception of the severity of the crash (‘smashed’ made them believe they saw broken glass)

experiment 2 conclusion: reconstructed memory

p creates original perception of the event then the leading question integrated this perception over time leading to reconstructed memory of the actual event