The reliability of cognitive processes: additional information on Loftus and Palmer (1974)
Maritza Zepeda Andersen
PreviousReliability of Cognitive Processes and Biases: Illusory CorrelationsNextThe reliability of eyewitness testimony
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Maritza Zepeda Andersen
Last updated
Reconstruction of auto-mobile destruction: An example of the interaction between language and memory. The Effect of leading questions on EWT.
Key Ideas/concepts/terms/theories: Cognitive processes of memory - reliable/not reliable - misinformation effect – Schema theory - memory and schema, inferences/interpretations of remembering (a more elaborate version of schema theory) - Neisser’s Model of Cognition - memory and perception – memory and Language – memory and perception - memory recall –- bias in thinking and decision –making.
One empirical study within the cognitive Approach is the Eyewitness testimony (EWT) - Elizabeth F. Loftus and J. C. Palmer in 1974. Their aim was to investigate how information supplied after an event, influences a witness’s memory for that event. A post-event information is information about an event provided (directly or indirectly) after the event already occurred. Also, Loftus and Palmer investigated whether the wording of questions (leading question - critical question) after an event influences recall in EWT. Recall is a form of retrieval. Retrieval required information from memory in the absence of any prompts. In their experiments they define a leading question as “one that, either by its form or content, suggests to the witness what answer is desired or leads him/her to the desired answer”. A misleading question is one of the forms that post-event information can take; misleading questions suggest information that is not entirely consistent with what actually happened. Their study on EWT demonstrates how the cognitive process of memory can be distorted by other information supplied after an event. It is important to note that experiment II consisted of two parts—experiment 1 and experiment 2 because there were two competing hypotheses.
Loftus took Bartlett’s idea of “reconstructive memory” (1932). A theory that views memory to be an active process of recreation of a past events as opposed to a passive process of retrieval. Human memory is not an exact copy of our experiences in life but rather a reconstruction of events that may be altered over time. Our memory is much more active than we realize, and we adjust what we remember so that memories fit our changing understanding of the world. Research shows that memory may be changed during storage, processing and retrieval. Definitions of some of the concepts relevant to reconstructive memory. – Misleading question: one of the forms that post event information can take; misleading questions suggest information that is not entirely consistent with what actually happened. – Post-event information: information about an event provided (directly or indirectly) after the event already occurred. – Recall – a form of retrieval, retrieval of required information from memory in the absence of any prompts. – Recognition: a form of retrieval that involves identifying an object as previously seen. Reconstructive Memory – The theory that views memory to be an active process of recreation of past events as opposed to a passive process of retrieval.
Bartlett demonstrated how memories are not accurate records of our experiences. It seems that we try to fit past events into our existing representations of the word, making the memory more coherent or make more sense for us. Bartlett showed how schemas can change how we recall stories. In this schema processing our memory processing is based on prior knowledge in the form of schemas which could result in distortion. Bartlett pioneering studies were supported by Loftus and Palmer (1974) who investigated mainly EWT, arguing that the evidence given by witness in court cases may be highly unreliable, and this is explained largely by the kind of misleading questions that witnesses are asked.
Some of Elizabeth Loftus’s first studies focused on how language can influence memories of a particular event. Research prior to the following two 1974 experiments suggested that people are quite inaccurate when asked to report numerical details regarding events. Also, as memory has been shown to be reconstructive in nature a reconstructive process, which means that memories are actively and consciously rebuilt when we are trying to remember certain things. Loftus and Palmer predicted that the wording of question could influence recall.
The theoretical background is the theory of the reconstructive nature of memory. The theory of reconstructive memory – There are cases of memory unreliability, such as memory distortions, when you remember things that did not actually happen (or not exactly the way they happened. – This phenomenon can be explained by b the theory of reconstructive memory which suggests that memory is not passive retrieval of information from a long-term store, but rather an active recreation of the event in the mind every time it is remembered. The theory recognizes two kinds of information: information obtained during the perception of the event and external post-event information. Over time, information from these two sources can get integrated to the extent that we are unable to tell them apart. A classic study supporting this theory is Loftus and Palmer (1974) were the researchers demonstrated that in an eyewitness situation people’s account of an event can be influenced by slightly differences in the way the question is formulated. The researchers also discussed and tested two potential explanations; genuine memory change or simple response bias (when the memory is unchanged, but participants tweak their responses based on what they think is expected of them). In an Eyewitness situation misleading post-event information can integrate with memory of the event and alter it. Aim of the study was to investigate if memory can be altered by misleading post-event information (in eyewitness situation). REMEMBER YOU WILL REPLICATE ONLY EXPERIMENT NUMBER 1, NOT THE EXPERIMENT 2. Conclusion of the experiment #1 demonstrated that misleading post-event information influences eyewitness account of an event. However, there could be two potential explanations for this finding. - There could be genuine memory change the question causes a change in the participant’s representation of the event). – There could be response bias (memory of the event does not change, but verbs of a higher emotional intensity cause participants to give higher estimates when they are uncertain). Post-events leading questions can lead to misremembering of an event by eyewitness. Elizabeth Loftus, her colleagues and others studying this cognitive phenomenon have shown that during the reconstruction phase our memories can be distorted if we are given false information about the event and this is “a theory” called the misinformation effect. Loftus and Palmer experiments were done on reconstructive memory and the impact of how asking questions to witness using specific words, can affect their recount (memory) when they have to testify in a courtroom (unreliability of eyewitness testimonies based on false memories; recalling an event that never happened and believing it to be true (as in experiment II). According to Loftus and Palmer, memory is a reconstructive process, which means memories are actively and consciously rebuilt when we are trying to remember certain things. These findings can also be interpreted from the perspective of schema theory: the high-intensity verb “smashed” used in the leading question activates a schema for severe car accidents. Memory is then reconstructed through the lens of this schema. Their models and theories show that the memory is amazingly inventive and fragile.
Method: The study to demonstrate Loftus and Palmer points consists of two laboratory experiments. They are both examples of an independent measures design. The IV in both experiments is the verb used in the leading questions. The dependent variable (DV) in the first experiment is the participant’s speed estimate in mph and the (DV) in the second experiment is whether the participant believed they saw glass.
In the experiment 1, 45 students at the University of Washington, USA, were divided into five groups of nine and were randomly allocated. It was a convenience sample. They showed to participants seven short films/videos (film-clips 5-30 seconds) taken from driver’s education courses that involved a traffic accident of some kind (A note on the films and speed estimates: Four of the seven films were staged crashes made specifically for education purposes, and so the precise speed in mph (miles per hour) of the vehicles is known). The results of actual speed of the car in the video (first number), and the mean guesses from all participants (second number). - 20 mph = 37.7 mph – 30 mph = 36.2 mph – 40 mph = 39.7/36.1 (there were two films of 40 mph). From this it shows that the different verbs can lead to different speed estimated.
Following each clip, the participants were first asked an open-ended question (questionnaire); participants were asked to write an account of the accident they had just seen (“give an account of the accident you have just seen”), which was followed by a series of specific questions (questionnaire) about the accident. They were asked to answer some specific questions, but there was one critical question = leading question that has to do with the speed in mph of the vehicles involved in the collision (participants were asked questions such as “how fast were the cars going when they hit each other”? The five groups were given five different verbs.
There were five conditions in the experiment (each with 9 participants) and the independent variable (IV) was manipulated by means of the wording of the questions. The critical question/leading question about how fast the cars were going when they……………………. each other? The dependent variable (DV) was the speed estimates in miles per hour given by the participants. In each condition, a different word or phrase was used to fill in the blank. These words were: smashed, collided, bumped, hit, and contacted (for example the word hit was replaced for the words “collided” or “smashed into”, etc. The mean speed estimates in mph for the various verbs were used and an analysis of variance (anova) (inferential statistics) was performed in the experiment I.
Findings: The results demonstrated that the phrasing of the questions brought about a change in speed estimate in mph. With smashed eliciting a higher speed estimate than contacted. There was a clear effect of the use of the different words. In this case, the more violent word (smashed) produced higher average speed estimates, when the witnesses were asked about “how fast were the cars going when they “smashed into” each other. (Mean estimate of speed (mph) verb Smashed 40.8 (40.5); Collided- 39.3; Bumped - 38.1; Hit - 34.0; Contacted - 31.8.).
Loftus and Palmer gave two potential interpretations/explanations for their findings. There could be genuine memory change (the question causes a change in the participant’s representation of the event) – There could be response bias (memory of the event does not change, but verbs of a higher emotional intensity cause participants to give higher estimates when they are uncertain).
In the first explanation they argue that the results could be due to response-bias factors, in which case the participant is not sure of the exact speed and therefore adjusts his or her estimate to fit in with the expectations of the questioner. They hypothesized that the verb “smashed” caused the participants to remember the crash differently. During the process of imagining the crash in order to remember the details and answer the questions, the verb may have affected the memory itself. The participants might have actually been imagining a more severe crash and a faster speed than was really portrayed in the video because of the leading question; when remembering the incident and playing it over in their minds, the verb “smashed” might have led to an actual change in the memory of the video. In the second explanation they argued that the results could be due to a distortion in the memory of the participants. In this research, they demonstrated how leading questions using specific words can affected people’s memory (participants had been misled by the wording of the interrogator). The memory of how fast the cars were travelling could have been distorted by the verbal label which had been used to characterise the intensity of the crash. In other words, that the participants might not have been sure about the speed and the verb simply led them towards a particular answer. If they were not sure of the speed and thought it was around 30 to 40 mph, the verb would have biased their answer in a particular direction. This does not tell us much about the reconstructive nature of memory and is more a possible limitation in the research methodology. This was interpreted in terms of how leading questions of police detectives and lawyers might influence witness’s recall and this have important implication for justice.
In conclusion, immediate recall can be distorted by the wording of a question. Leading questions can alter the memory of events and lead to unreliable eyewitness testimony. Leading questions can influence the reconstruction of memories. The study clearly demonstrated that misleading post-event information influences eyewitness accounts of an event. The connotations of a specific word can cause individuals to perceive events differently. The researcher proposed that two types of information are stored: the perception of the original event, and external information after the event. These two types of information might merge over time, causing accuracy errors.
*However, this data does not provide strong support for this hypothesis, so they conducted a second experiment. Wording can also change information already stored in memory (e.g., the memory of the car crash was reconstructed to incorporate broken glass in the second experiment).
The study was conducted under controlled conditions. The laboratory conditions allowed the researchers to control any potentially confounding variables. The standardized procedure and control of variables make this study easy to replicate which increases its reliability (reliability). The videos in the first experiment were randomized between groups to reduce any possible order effects (reliability). Application to life. Understanding that memory can be influenced (and this is unreliable) by leading questions is invaluable when considering Eyewitness testimony and interviewing. Application in Law Reinforcement when questioning Eyewitness. This study represents part of Elizabeth Loftus’s pioneering work in calling to attention the unreliability of EWT under certain conditions: this and others research of hers has had a huge influence on the questioning of eyewitness by the police. The findings of this study have implications for examination of witnesses and how courts should consider eyewitness testimony. Questions that lead a witness to answer in a particular way lessen the accuracy of testimony given by witnesses to crimes. As demonstrated, a single change of word can bring significant changes in how an event is remembered. The participants were asked to watch potentially upsetting traffic accidents, however not individuals were seen to be hurt in the films. (ethics)
Limitations: 45 participants is not a high number, especially when this was further divided into 5 groups (generalizability). The participants are representative of a narrow population. American students only so cannot generalize to other population (generalizability). Is this study limited in population validity? For example, look at the accuracy of their guesses in the first experiment – is this evidence that perhaps these results might not apply to other groups of people? The use of students as participants. Students may be very different from other people and may not be fully representative of people in general. For example, students are used to remembering useless information, and are usually good at memory tasks compared with other people. Loftus and Palmer have themselves pointed out that the participants might have been prone to response bias: for example, the nature of the words may have prompted the participants to think that high or low speed estimate was expected of them depending on the verb they were presented with. The participants will have had limited driving experience which may have affected the strengths of the leading question. Experience drivers may be less affected by the strengths of the word as they will rely on their own judgement more (validity). Watching a video is not the same as witnessing an actual car crash in real life (validity). Watching a traffic accident for a few seconds on a film screen is nothing like experiencing the event in real life, so the study lacks ecological validity. In the other hand it would be unethical expose participants to real life accident. The participants were asked to watch potentially upsetting traffic accidents, however not individuals were seen to be hurt in the films. (ethics). In Loftus and Palmer (1974) post-event information was verbal and the response to the experimental task (answering a question about broken glass) was also verbal. Some critics pointed to this as a limitation of the study, because visual and verbal information might be stored separately, and the leading question might have interfered with the verbal storage but not the visual one (methodology). So, it remained to be seen whether or not verbal post-event information could be integrated with visual information obtained originally at the time of the event.
One of the main strengths of Loftus’ argument is its wider implications, recommended that in trial judge be required to instruct the jury that it is not safe to convict on a single eyewitness testimony alone, except in exceptional circumstances or when there is substantial corroborative evidence. The findings of the studies have contributed to better identification techniques in criminal cases such as helping innocent people from being prosecuted and families being torn apart based on their explanation of the false memory phenomenon (application of findings). She questions the accuracy of those memories and the techniques used to resurface such memories (misleading questions, therapy, etc). Loftus asserted that, after copious scientific research, she has found that many potential jurors do not understand the limits of memory. The theory of reconstructive memory and research into the reliability of eyewitness testimony has triggered many social and even political campaigns related to legal practices. These revolved around cases where accusations were made based on eyewitness testimony alone, as well as the phenomenon of false memories. Loftus reconstructive hypothesis has also meant that the police and lawyers are urged to use as few leading questions as possible (e. g. questions suggesting to the witness the desired answer), although in reality this practice is still widely carried out.
Another argument against applicability of these results to natural conditions is that real-life eyewitness testimony often involves recognition (recognizing a stimulus as something you had already seen) rather than recall (in the absence of a stimulus). Eyewitness testimony is often required in recognizing individuals suspected of committing a crime. Also, in the previous example we saw that leading questions (with verbs of varying emotional intensity) may provide post-event information that contributes to reconstructive memory. In real-life situations, however, post-event information might take more aggressive forms, for example, providing a person with misleading information. This might happen in police interrogations or in the presence of other conflicting testimonies.
The theoretical background is the theory of the reconstructive nature of memory. Post-event leading questions can lead to misremembering of an event by eyewitness. Aim: to investigate how information provided after an event can influence eyewitness testimony. The broken glass manipulation.
Key Ideas/concepts/terms/theories: Cognitive processes of memory - reliable/not reliable - misinformation effect – Schema theory - memory and schema, inferences/interpretations of remembering (a more elaborate version of schema theory) - Neisser’s Model of Cognition - memory and perception – memory and Language – memory and perception - memory recall –- bias in thinking and decision –making, false memories.
Method: A second experiment with some similar procedure. Laboratory experiment, an independent measures design, convenient sample. There were 3 conditions, and the independent variable (IV) was manipulated by the wording of the question (critical/leading question). The IV was the verbs smashed and hit and not asked any questions about the speed in mph. However, the (DV) in the second experiment is whether the participant believed they saw a broken glass – response Yes or No. 150 students were placed into three different groups, but all watched the same short film (in smaller groups). The film which contained a 4 second scene of a multiple car accident (the entire film lasted for less than one minute and the accident part of film lasted 4 seconds) and were then questioned about it; they were given a questionnaire. The first question was again open-ended and asked the participants to describe the accident in their own words. This was followed by a series of specific questions, with one critical question/leading question. The 3 conditions and number of participants: 50 of the participants were asked “how fast were the cars going when they smashed into each other? 50 of the participants were asked “how fast were the cars going when they hit into each other? 50 of the participants were not interrogated about the speed of the vehicles (were not asked any questions about the speed).
One week later, all the participants returned and without viewing the film again, they answered a series of ten questions about the accident. One of the ten questions appeared randomly in a different order for each participant and asked: The critical question/leading question was “Did you see any broken glass? (There was in facto no broken glass in the film). And there was a checkbox for Yes or No. An independence chi-square test (inferential statistics) on these responses was used for experiment II.
Results: Once again the results showed that the speed estimates of those asked about the cars with the v eb “smashed” were higher than those with the verb “hit” (10.46 mph and 8.00 mph) (Response Yes when smashed -16 (32%), when hit – 7 (14%) and control group (6 (12%); Response No, when smashed -34 (68%), when hit - 43 (86%)and when control – 44 (88%). These results show a significant effect on the verb in the question on the misperception of glass in the film. Those participants that heard the word smashed were more than twice as likely to recall seeing broken glass. If the verb smashed significantly increased the memory of broken glass when there was none, this is stronger evidence to show that the verb as acting as false information which was actually changing the memories of participants in this condition.
Conclusion: Experiment 2 was conducted to rule out the second explanation. Since it demonstrated that the verbs of a higher emotional intensity may cause participants to recall events that never occurred, researchers concluded that we should reject the response bias explanation and accept genuine memory change. The second explanation; the response bias explanation – There could be response bias (memory of the events does not change, but verbs of a higher estimates intensity cause participants to give higher estimates when they are uncertain)
Interpretations of results: The results provide some evidence for the explanation that the misinformation effect was occurring. Perhaps the verb “smashed” was influencing people’s collections of the crash and they were remembering it as being more severe than it really was, which is why they could remember seeing broken glass even when there was not any in the original video.
In reconstructive hypothesis, Loftus and Palmer argued that two kinds of information go into a person’s memory of an event; these types of information are influential in making up someone's memory. The first is the information obtained from perceiving an event (e.g., witnessing a video of a car accident), The first information is the perception of the details during her actual event, Loftus and Palmer interpretation: They argue that the results could be due to response-bias factors, in which case the participants are not sure if there where glass or not and therefore adjusts his or her estimate to fit in with the expectations of the questioner. To account for the results of the second experiment, they developed the following explanation called the reconstructive hypothesis. And the second is the other information supplied to us that can be processed after the event itself; information from our environment might impact our memory processes, which could lead to distortions. (e.g., the question containing hit or smashed).
They argue that the verb “smashed” provides additional external information because it shows that the cars did actually smash into each other. The verb that has connotations of a stronger and more severe impact than hit or collided could result in a memory of the incident that never happened, like remembering broken glass when there was none. Remember that the second question was asked an entire week after the original videos were viewed and the leading questions asked. The participants are reconstructing their memories after one week and the difference between the scores is quite significant. Over time, the information from these two sources may be integrated in such a way that we are unable to tell from which source some specific detail is recalled. All we have is one “memory”.
Evaluation/criticism: See experiment 1 for some of the strengths and limitations too - One way in which we could criticise this argument is to recognise that it is not only the type of question asked but also many other factors which could influence your memory of an event. Other factors which include food, alcohol, emotions, environment, who you were with, what the event meant to you, and so forth. Some psychologists have made a further criticism of the argument. They do not agree with Loftus that post event information changes the witness’s original memory, never to be retrieved again. They suggest that witnesses merely follow the questioner’s suggestions, leaving the original memory intact for retrieval under appropriate conditions. In this experiment the participants first form some memory of the video they have witnessed. The experimenter then, while asking “about how fast were the cars going when they smashed into each other?” supplies a piece of external information, namely, that the cars did indeed smash into each other. When these two pieces of information are integrated, the participant has a memory of an accident that was more severe than in fact it was. Since broken glass corresponds to a severe accident, the participant is more likely to think that broken glass was present.
The theory of reconstructive memory and EWT. There are cases of memory unreliability, such as memory distortions, when you remember things that did not actually happen (or not exactly the way they happened). These phenomena can be explained by the theory of reconstructive memory which suggest that memory is not passive retrieval of information from a long-term store, but rather an active recreation of the event in the mind every time it is remembered. The theory recognizes two kinds of information: information obtained during the perception of the event and external post-event information.
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