Reliability of memory Evidence that memories may be reliable Read the following two studies. How strong an argument do they make with regard to the reliability of memory? How do they compare to: 1. 2. 3. 4. Loftus and Palmer Neisser and Harsch Loftus and Pickerell Shaw et al Study I. Yuille and Cutshall (1986) The aim of the study was to determine whether leading questions would affect memory of eyewitnesses at a real crime scene. In other words, the aim was the same as Loftus & Palmer's (1974) study, but in this case, it would be a field experiment done under naturalistic conditions. The crime scene was in Vancouver. A thief entered a gun shop and tied up the owner before stealing money and guns from the shop. The owner freed himself, and thinking that the thief had escaped, went outside the shop. But the thief was still there and shot him twice. Police had been called and there was gunfire - and the thief was eventually killed. As the incident took place in front of the shop, there were eyewitnesses - 21 were interviewed by the police. The researchers chose this incident to study because there were enough witness and there was forensic evidence available to confirm the stories of the eyewitnesses. The researchers contacted the eyewitnesses four months after the event. 13 of the eyewitnesses agreed to be interviewed as part of a study. They gave their account of the incident, and then they were asked questions. Two leading questions were used. Half the group was asked if they saw a broken headlight on the getaway car. The other half was asked if they saw a yellow panel on the car (the panel was actually blue). They were also asked to rate their stress on the day of the event on a seven-point scale. It was found that eyewitnesses were actually very reliable. They recalled a large amount of accurate detail that could be confirmed by the original police reports. They also did not make errors as a result of the leading questions. 10 out of 13 of them said there was no broken headlight or yellow quarter panel, or that they had not noticed those particular details. © John Crane, InThinking http://www.thinkib.net/psychology/ 1 The researchers found that the accuracy of the witnesses compared to the original police reports was between 79% and 84%. Study II. Bahrick et al (1975) The aim of the study was to investigate the reliability of autobiographical memory over time - specifically the names and faces of the people that went to school with us. Nearly 392 participants aged 17 – 74 were tested. Some of the participants had been out of high school only two weeks. At the other end of the continuum, some of the participants had graduated 57 years earlier. In order for the participants to be selected, they had to be in a class of at least 90 graduates and there had to be a published yearbook available for the graduating class. The participants were asked to do five tests: • • • • • A free recall test: Name as many people as you can from your graduating class. A photo recognition test: 10 cards, each with five photos. They were asked with of the five photos was taken from their own yearbook. 8-second limit. A name recognition test: 10 lists of names, each with only one name from the graduating class. Participants were asked to identify the person from their class. Matching tests: 10 cards each with five pictures. A name was written across the top of the page. The participants were asked to identify the correct photo to match the name. Picture cueing test: The participants were presented with 10 portraits one by one and asked to write down the name of the person in the photo. A 15 second time limit. The free recall test was always given first and then participants were randomly assigned to the order of the remaining tests. For each question participants were asked to indicate their degree of confidence on a three-point scale: 3 being certain, 2 being probable and 1 being a guess. Results of the study showed that participants who were tested within 15 years of graduation were about 90% accurate in identifying names and faces. After 48 years they were accurate 80% for identifying names and 70% in identifying faces. Free recall was worse. After 15 years it was 60% and after 48 years it was 30% accurate. This demonstrates that memories of the names and faces of people in our past are highly reliable over time; however, it also shows that recognition is better than recall. © John Crane, InThinking http://www.thinkib.net/psychology/ 2 I feel that the studies arguing for the reliability of memory are more convincing and reliable than the studies arguing against it. I feel this because these two studies were done in a more naturalistic setting, and therefore would provide more natural responses from the witnesses without any pressures of a lab experiment. Ecological validity is high in these experiments. I think memory is very volatile and flexible, and can vary in it's reliability. I feel that all of these studies have many disadvantages that can lead to unreliability of memory. To an extent, it can be trusted, but to a very, very, specific, narrow, and focused extent.