Leading questions are questions which expect a certain answer. The Loftus and Palmer study demonstrates how using certain words in a question can affect the answer. This was a laboratory experiment with five conditions. Participants were shown a video of a car accident involving a number of cars. They were then asked to describe what had happened as if they were eyewitnesses. The participants were asked a number of questions such as “About how fast were the cars going when they (hit/smashed/collided/ bumped/ contacted – the five conditions) each other?” when the word ‘smashed’ was used the speed estimated was faster – an average of 41mph, but when the word ‘hit’ was used the speed estimated was slower – an average of 34mph. Furthermore, a week later the participants were asked “Did you see any broken glass?” 32% of participants who heard ‘smashed’ said that they had and only 14% of participants who heard ‘hit’ said they had. In fact there was no broken glass in the video.
Exposure time is the length of time witnesses are exposed to an event. In a study by Loftus participants were shown a 30 second video of a stimulated bank robbery, they were then asked how long the robbery lasted. The results showed participants tend to overestimate the length of the robbery. The average estimated time was 2 ½ minuets.
Another factor that can affect eyewitness testimony is weapon focus - when a witness is distracted from other characteristics of the situation, such as identification of the robber, by the presence of a gun. In a study by Loftus participants were shown a video which had two versions. In one version a man pointed a gun at a cashier in a restaurant and she gave him money. In the other version a man gave the cashier a cheque and she gave him money. The eye movements of the participants were monitored and the results showed that the participants who saw the weapon version were fixated more by the gun then the participants who saw the non weapon version. Recall in the weapon version was poor and participants were less able to identify the man.
The violence of an event can also affect recall. In the Loftus and Burns study participants were shown one of two versions of a stimulated bank robbery on a video. One version included a scene of a boy being shot in the face. Recall of the more violent video was less accurate. It is possible that that the shock associated with the violent event disrupted the consolidation and processing of memory.
Each study suggests eyewitness testimony is unreliable. All research into eyewitness testimony has been laboratory experiments which lack external or ecological validity. They lack this because the experiments do not have an emotional impact, watching a video may not be as emotional as real life situations. However due to the research being laboratory experiments there is high control over the confounding variables.
A study that has ecological or external validity is a study by Yuille and Cutshall. In this study participants who had witnessed a genuine armed robbery were asked to recall the events of the robbery four or five months later. This study is naturalistic due to the participants actually being there when the robbery took place. Recall in this study was not susceptible to misleading questions and there were few, if any, facts recalled by the participants that had been reconstructed. This shows that eyewitness testimony of events is not necessarily as inaccurate as laboratory experiments would suggest. In general Yuille and Cutshall say eyewitness testimony is reliable, Loftus say’s eyewitness testimony is unreliable but both agree that there is weapons affect
The results from laboratory experiments suggest eyewitness testimony is unreliable. However one naturalistic experiment in general shows eyewitness testimony to be reliable. Both methods agreed that there is a weapons affect and that to give a definite answer to the question set, more naturalistic experiments need to be performed.
