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Eyewitness Memory ~ Is It Reliable?
Eyewitness Memory - It does indeed appear to be unreliable much of the time, though this depends largely on the manner in which it is employed, but when correct, eyewitness accounts can aid in the conviction of many guilty parties.
Several studies have empirically validated (based on, concerned with, or verifiable by observation or experience rather than theory or pure logic) the increased effectiveness of the cognitive interview. This technique does work, and for that reason a number of policing organisations have incorporated it into their questioning techniques. By utilising such methods, the dire consequences of inaccurate eyewitness testimony can be minimised.
However, eyewitness memory, no matter how accurate it seems, should always be taken critically in the face of no other evidence.
General Errors in memory ~
Estimator Variables -
There are many variables in the category of distinguishing the types of errors within eyewitness memory. One being 'estimator variables'. This takes into account that memory is best recalled with a medium level of stress. It has been noted that stress figures very highly in the ability of the witness to accurately recall, most especially when that witness is either very stressed, which, given the circumstances, there is always the potential for very high stress/arousal levels, and also while very relaxed. Thus, is has been proven that eyewitness memory recall is best harvested under medium levels of arousal.
It is worth mentioning that many eyewitnesses claim they will never forget certain occurrences, because of the volatile nature of them, yet, when tested on this with the space shuttle Challenger incident, almost immediately after, eyewitness accounts were taken, and then again 3 years later, and the results were astounding. So much had changed, but the only consistency was the way they felt on the day, therefore their emotional levels remained consistent, though much of the rest of what happened, had changed with each of the witnesses. This is known as 'flashbulb memory' because the mind literally takes a flashbulb image of what happened and ingrains it within the memory to such a degree that it will be remembered 'as though it happened yesterday', to quote Neisser et al.
Weapon Focus -
Loftus suggests that weapon focus occurs because the weapon has taken the focus away from lesser visual stimuli, such as the face of the assailant, due to the obvious impact of the weapon upon human life. Loftus was able to show sufficient evidence that the focus of the mind remained longer on the weapon than on any other visual stimuli during slideshow representations. Kramer et al, found that weapon focus occurred even when arousal was low, whereas Pickel (1998) argued that it was the 'unusualness' rather than the degree of threat that is the key variable producing the weapon focus effect; this is supported by two experiments he conducted in 1999.
Confidence Of Witness -
Confidence is NOT RELATED to accuracy. This is one of the main issues with eyewitness testimony; confidence vs. accuracy. There is so much to consider, and not all necessarily go hand in hand. It has been proven that it makes almost no perceivable difference to the situation when an individual eyewitness states "I am absolutely sure", and "I can't be totally sure". The former is only slightly more accurate than the latter. Conversely, if one witness is informed of other witnesses and their testimonies, particularly if the statements given happen to coincide, this then raises the confidence of the individual eyewitness, though they may not be aware of it at the time. Knowing this information about fellow eyewitnesses can also serve to unconsciously boost the confidence on the witness stand. On the other hand, the opposite effect can also occur if witnesses are made to understand that other witnesses were not able to make a clear choice in a line up, for example, which can just as quickly deflate the confidence of individual witnesses, making for difficulties in finding more helpful clues, that assist in information gathering.
To add a personal note here, I found it shocking that it was deceptively easy to manipulate the confidence of the eyewitness where they would go from not being certain, to being absolutely certain at a later date, and then sentencing commence from their testimony, of which they seemed not fully consciously aware. In this manner, Wells and Bradfield were able to show that when the eyewitness confidence was increased, (i.e. being told they are correct) it was found to have distorted other information stored in the memory. Those interviewed reported that they were better able to recall finer details of the assailant's face, or having paid better attention to the actual event as it transpired, which allowed for easier identification, than those who believed themselves incorrect.
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Eyewitness Memory - How Can It Be Applied?
The Cognitive Interview ~
In today's court system one of the strongest pieces of evidence, or that most commonly accepted as fact by a jury, is eyewitness testimony. When correct, eyewitness accounts can aid in the conviction of guilty parties.
The cognitive interview is a questioning technique designed to optimise accurate retrieval of experienced information. There are four components or 'retrieval mnemonics' (the study and development of systems for improving and aiding the memory) in the cognitive interview:
Context Reinstatement -
1). The questioner should attempt to mentally recreate the environmental and contacts that occurred at the time in which the crime was experienced, although according to Tulving and Thomson, 1973, we have "better recall if we are in the same place, same emotional state, and/or the same context as that in which the memory was encoded". This 'phenomenon' is known as the Encoding Specificity Hypothesis.
Report Everything -
2). The officer should attempt to encourage the reporting of every single detail, even if it seems to be completely irrelevant. If it occurred during, or surrounding the incident, then it should be reported.
These two components are based on the principle that with increased overlap and consistency between the events of the crime and the recreated situation there is an increased likeliness that recall will be more significant.
Change The Order -
3). The officer may try alternative ways to go through the crimes timeline. The incident can be recounted in different orders such as a reverse or normal timeline. It is worth noting that memories form through a network within our minds, and if one approach toward unlocking them doesn't work, trying another route towards gaining access just might
Change The Perspective -
4). A final technique is to recall the situation through multiple perspectives. The witness may be asked to recount what other prominent characters and witnesses perspectives of the event may have been, whether they were different perspectives or not. To elaborate, we know that we cognitively process information into various "folders" within the mind known as schemas. Sometimes, recall is not fully accurate, due to "filling in the gaps" to match an existing schema. We also tend to forego information within a schema, unless it is very salient, deeming it as unimportant, or no longer necessary.
These final principles follow the perspective that information that has been observed can be retrieved through multiple routes. If one can do this, it is productive to maximise the number of retrieval routes used.
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False Memories/False Memory Implantation ~
The Use Of Hypnosis -
There are some circumstances in which it is thought that hypnosis can be of benefit in memory recall. The main problem with this is that it is very easy for the hypnotist to implant false memories within the mind of the witness, leaving that witness to believe that the memories they recall are true and factual, even if they have never occurred. There are also occasions in which the witness tends to make use of the facility to lie. The loophole is that if the information proves to be inaccurate, the witness may plead ignorance in the case of being hypnotised, stating that the information given and gathered was supposedly in good faith.
It is suggested that if hypnosis is to be used as the way forward, that the entire interview should be recorded for both posterity, as well as for use as evidence, and that there should be only two people within the room whilst the interview takes place - the hypnotist and the witness. This is to aid the continuity of the interview, and keep other aspects out, such as memory implantation via a third party, or the asking of additional questions, or making comments by an individual other than the hypnotist. Another main problem is how memory is assumed to be an exact copy of a situation, or an actual fact of what actually occurred. Memory doesn't tend to work in this manner. The ability to cognitively recall every finite detail, right down to the last hair, figures largely on stress factors, and emotional responses to a given situation on part of the eyewitness, therefore, many finer details may well be forgotten altogether due to many factors which were present at the time the event took place, and the time the interview was conducted.
Copyright ~ Silver Rainbolt 2006 ~ All Rights Reserved
You may not legally copy any part of this document without prior written consent of the author. Doing so, infringes upon copyright, and is punishable under the law.
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