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Sunday, January 23, 2011


Even when we believe that we are ‘playing back’ some previous event or information in our mind, as if it were a videotape, we are actually constructing a memory from bits and pieces that we remember, along with general knowledge about how these bits should be assembled. This strategy is usually very adaptive, minimizing our need to remember new things that are very similar to things we already know. But sometimes there can be a blurring between what actually happened and what has been imagined or suggested.

Reality monitoring
The issue of reality monitoring – identifying which memories are of real events and which are of dreams or other imaginary sources – has been addressed by Johnson and Raye (1981). These researchers maintain that the qualitative differences between memories are important for distinguishing external memories from internally generated ones. They argue that external memories have stronger sensory attributes, are more detailed and complex and are set in a coherent context of time and place. By contrast, they argue that internally generated memories have more traces of the reasoning and imagining that generated them. Although Johnson (1988) found support for these differences, applying them as tests can lead to accepting memories as real, even when they are not. Morris (1992), for example, asked participants to recall details from a videotape and to report both their confidence and the presence or absence of clear mental imagery and detail. Although clear images and details were found to occur more often with correct reports, their presence led people to be overly confident: incorrect details accompanied by mental images were reported with greater confidence than correct details that lacked these images. So there does not seem to be any sure way of distinguishing between ‘real’ and ‘imagined’ memories. Related to the concept of reality monitoring is source monitoring – being able to successfully attribute the origin of our memories (e.g. being able to state that we heard a particular piece of information from a friend rather than hearing it on the radio news broadcast). Errors in attributing memories can have important consequences – for example, during eyewitness testimony (Mitchell & Johnson, 2000).

The misinformation effect
The distortion of memory through the incorporation of new information has been an important research topic for psychologists concerned both with the practical implications for eyewitness testimony, and with theoretical accounts of the nature of memory. Loftus and colleagues have explored in depth the misinformation effect (Fruzzetti et al., 1992; Loftus & Loftus, 1980). This arises when misleading information is introduced indirectly. For example, Loftus, Miller and Burns (1978) showed participants a series of slides along with the story of a road traffic accident. Later, the participants were questioned about the event. One of the questions was slightly different for half of the participants, in that it referred to a Stop sign instead of a Yield (Give Way) sign. Participants who were asked the question with the misleading information were more likely to identify falsely that particular slide in a later recognition memory test. These participants tended to choose the slide with the road sign that had been mentioned in the misleading question, rather than the one they had actually seen. Loftus and colleagues have repeatedly demonstrated similar distortions of memory reports after intervening, misleading questioning. The findings are robust and have implications for the sort of questions that eyewitnesses of crimes and accidents should be asked if their recall is to be as accurate as possible. However, the basis of the misinformation effect is disputed (see Chandler & Fisher, 1996, for a review). It is possible that the participants’ original memories are permanently distorted by the questioning, but it is also possible that the questions supply information that the participants would not otherwise be able to remember (see Saunders & MacLeod, 2002).

False memories
Related to the misinformation effect, but with more potentially serious consequences, are recovered and false memories (Ceci & Bruck, 1995; Loftus & Ketcham, 1994). Under therapy, some adults have recovered memories of alleged abuse in childhood that have led to criminal convictions (Loftus & Ketcham, 1994). But substantial research has shown that, under certain circumstances, false memories can also be created. Sometimes these are benign (Roediger & McDermott, 1995). However, it is also possible to create, using suggestions and misleading information, memories for ‘events’ that the individual believes very strongly happened in their past but which are, in fact, false (Ceci & Bruck, 1995; Loftus & Ketcham, 1994). So it remains at least plausible that some abusive events that people ‘remember’ are in fact false memories.

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