Loftus and Palmer (1974)
Aim: To test their hypothesis that that language used in eyewitness testimony can differ memory.
Method: Forty-five American students formed an opportunity sample. This was a laboratory experiment with five conditions, only one of which was experienced by each participant (an independent measures design). Participants were shown slides of a car accident involving a number of cars and asked to describe what had happened as if they were eyewitnesses. They were then asked specific questions, including the question “About how fast were the cars going when they (hit/smashed/collided/bumped/contacted ) each other?” Thus, the IV was the wording of the question and the DV was the speed reported by the participants. A week after the participants saw the slides they were asked “Did you see any broken glass?” There was no broken glass shown in the slides.
Findings: The estimated speed was affected by the verb used. The verb implied information about the speed, which systematically affected the participants’ memory of the accident. Participants who were asked the “smashed” question thought the cars were going faster than those who were asked the “hit” question. The participants in the “smashed” condition reported the highest speeds, followed by “collided”, “bumped”, “hit”, and “contacted” in descending order. When people were asked a week after viewing the film whether they saw any broken glass at the scene (there was none), people in the smashed group were more likely to say yes. Therefore, a leading question that encouraged them to remember the vehicles going faster also encouraged them to remember that they saw non-existent broken glass. The question appears to have modified the memory itself.
Conclusions: This research suggests that memory is easily distorted by questioning technique and information acquired after the event can merge with original memory causing inaccurate recall or reconstructive memory.
The addition