A growing body of evidence suggests that the information entered into memory is often altered in various ways over time—and these alterations can reduce its accuracy and change its meaning. Such changes fall under two major headings- memory distortion, alterations in what is retained and later recalled, and memory construction, the addition of information that was not actually present.
Almost everyone has had firsthand experience with memory distortion. For example, when we look back on our own behavior in various situations, we often tend to perceive it in a favorable light; we remember saying or doing the “right” thing, even if this wasn’t quite what happened. Distortion in memory can also occur in response to false or misleading information provided by others.
If someone’s comments suggest a fact or detail that is not present in our memories, we may add that fact or detail. Unfortunately, such effects often occur during trials, when attorneys pose leading questions to witness’s questions that lead the witnesses to “remember” what the attorneys want them to remember.
What accounts for memory distortions? In many cases they seem to involve the operation of schemas—structures representing individuals’ knowledge and assumptions about aspects of the world. Schemas are developed through experience and act something like mental scaffolds, providing us with basic frameworks for processing new information and relating it to existing knowledge—including knowledge held in long-term memory.
Once schemas are formed, they exert strong effects on the way information is encoded, stored, and later retrieved. These effects, in turn, can lead to important errors or distortions in memory. Perhaps such effects are most apparent with respect to encoding.
Current evidence suggests that when schemas are initially being formed—for example, when you are first learning about the activities, roles, and responsibilities of being a college student information inconsistent with the newly formed schema is easier to notice and encode than information consistent with it.
Such inconsistent information is surprising and thus seems more likely to become the focus of our attention. After the schema has been formed and is well developed, in contrast, information consistent with it becomes easier to notice and hence to remember. It is the operation of schemas that, in part, accounts for the fact that in many cases we are more likely to notice and remember information that supports our beliefs about the world than information that challenges them.
Another important cause of distortion in memory involves our motives. We often distort our memories in order to bring them in line with whatever goals we are currently seeking. For example, suppose that you like someone; this may lead you to want to remember positive information about him or her. Conversely, if you dislike someone, you want to remember negative information about this person.
Effects of this kind were observed in a careful series of studies conducted by McDonald and Hirt (1997). These researchers had participants watch an interview between two students. The experiments varied participants liking for one of the two individuals by having this stranger act in a polite, a rude, or a neutral manner.
When later asked to recall information about this person’s grades (information that was provided during the interview), those participants who were induced to like the stranger distorted their memories so as to place this person in a more favorable light, whereas those induced to dislike the stranger showed the opposite pattern. In this and many other situations, then, our memories can be distorted by our current motives.
A final way in which memories can be distorted involves confusions concerning the sources of information in memory. We often make errors in source monitoring—the process of identifying the origins of specific memories. In other words, we remember information stored in memory, but we attribute it to the wrong source.
A related effect involves reality monitoring—the process of deciding whether memories stem from external sources (events we actually experienced) or from internal sources (our imagination or thoughts). Both source monitoring and reality monitoring have important practical effects. For instance, errors in source monitoring Eyewitness Testimony may play a role in eyewitness testimony.
Eyewitnesses, it turns out, Information provided by witnesses aren’t nearly as accurate as is widely believed, and one kind of error to crimes or accidents they make is attributing information they recall to one source, such as actions by a defendant rather than to another, such as leading questions by lawyers or police.
Not only can memories be distorted; they can also be constructed. In other words, people can recall events that did not actually occur, or experiences they never really had. Constructed memories can have important effects; for instance, they can lead to false charges of child sexual abuse when adults construct memories of such treatment even though it never actually occurred.
Unfortunately, a growing body of research evidence suggests that false memories are both persistent and convincing—people strongly believe that they are real. This, in turn, has important implications for several aspects of the legal system, including eyewitness testimony.
Eyewitness testimony evidence given by persons who have witnessed a crime—plays an important role in many trials. Is such testimony really accurate?
The answer provided by careful research is clear: Eyewitnesses to crimes are far from infallible. In fact, they often falsely identify innocent persons as criminals, make mistakes about important details concerning a crime, and even sometimes report “remembering” events they did not actually see. Why do such errors occur? Not, it appears, because the witnesses are purposely faking their testimony.
On the contrary, most people really try to be as accurate as possible. Rather, these errors occur because of several factors that produce distortions in memory. One of these is suggestibility—witnesses are sometimes influenced by leading questions and similar techniques used by attorneys or police officers. Errors also occur with respect to source monitoring—eyewitnesses often attribute their memories to the wrong source.
For instance, they identify a suspect in a police lineup as the person who committed a crime because they remember having seen this individual before and assume this was at the scene of the crime; in fact, the person’s face may be familiar because they saw it in an album of mug shots.
Another source of error is an effect known as the illusion of out-group homogeneity—the fact that people outside our own group seem more similar in appearance and characteristics than people within our own group; because of this illusion it is easy to identify an out-group individual incorrectly as the perpetrator of a crime.
Given all these potential sources of error, it is not surprising that eyewitnesses are not nearly as accurate as our legal system assumes. And because jurors and even judges tend to place great weight on the testimony of eyewitnesses, such errors can have serious consequences: Innocent persons may be convicted of crimes they did not commit—or, conversely, persons guilty of serious crimes may be wrongly cleared of the charges against them. Indeed, recent evidence indicates that the single largest factor accounting for such miscarriages of justice is faulty eyewitness testimony.
Can anything be done to enhance eyewitness’s accuracy? Fortunately, research on memory offers some answers, and these have been combined into suggestions for conducting improved interviews with witness’s interviews that may enhance their ability to remember crucial information accurately.
In such cognitive interviews eyewitnesses are asked to report everything they can remember; this provides them with multiple retrieval cues and can increase accuracy of recall. In addition, they are sometimes asked to describe events from different perspectives and in several different orders, not just in the order in which the events actually occurred. These and other steps seem to increase the accuracy of eyewitness testimony, but they are far from a perfect solution, so the basic problem remains.