Memory distortion: an adaptive perspective

Memory is prone to distortions that can have serious consequences in everyday life. Here we integrate emerging evidence that several types of memory distortions - imagination inflation, gist-based and associative memory errors, and post-event misinformation - reflect adaptive cognitive processes that contribute to the efficient functioning of memory, but produce distortions as a consequence of doing so. We consider recent cognitive and neuroimaging studies that link these distortions with adaptive processes, including simulation of future events, semantic and contextual encoding, creativity, and memory updating. We also discuss new evidence concerning factors that can influence the occurrence of memory distortions, such as sleep and retrieval conditions, as well as conceptual issues related to the development of an adaptive perspective.     

Memory for previous recall: a comparison of free and cued recall

Case studies of individuals who claimed to have recovered previously repressed memories of abuse during situations that involved memory cueing revealed that some individuals had discussed abuse with others during an earlier time period. Termed the ‘forgot‐it‐all‐along’ effect, this phenomenon has legal implications for statutes of limitations. Two experiments provide evidence for differences between free recall and more directed (recognition or cued recall) test conditions in the accuracy of memories for previous recall. Participants more often erred by claiming they had not previously remembered recognized (Experiment 1) or cued (Experiment 2) sentences than freely recalled sentences, and this difference was obtained even when the number of remembered sentences was equivalent across conditions (Experiment 2). These studies document that memory for previous recollection is less accurate for cued memories even when remembered events do not produce feelings of shock or surprise. Copyright © 2002 John Wiley & Sons, Ltd.     

Memory distortion in people reporting abduction by aliens

False memory creation was examined in people who reported having recovered memories of traumatic events that are unlikely to have occurred: abduction by space aliens. A variant of the Deese/Roediger-McDermott paradigm (J. Deese. 1959; H. L. Roediger III & K. B. McDermott, 1995) was used to examine false recall and false recognition in 3 groups: people reporting recovered memories of alien abduction. people who believe they were abducted by aliens but have no memories, and people who deny having been abducted by aliens. Those reporting recovered and repressed memories of alien abduction were more prone than control participants to exhibit false recall and recognition. The groups did not differ in correct recall or recognition. Hypnotic suggestibility, depressive symptoms, and schizotypic features were significant predictors of false recall and false recognition.     

Memory for medical history: Accuracy of recall

Medical diagnosis often depends on the ability of patients to recall and report their medical history. In this study 104 people kept health diaries for 3 months, recording the incidence, frequency, data, duration, and severity of health events (symptoms, illnesses, injuries, visits to health professionals, and medication). Memory for the events recorded was tested immediately after the diary-keeping period or at 1 month or 3 months later. Effects of age, gender, education, health status, anxiety, and retention interval were observed. With a free recall procedure only 47 per cent of health events were recalled. Following the free recall two different kinds of intervention were compared. Use of a recognition checklist yielded recall of 29 per cent of the forgotten events but with a cognitive interview procedure only 6 per cent of the forgotten items were retrieved.     

Memory monitoring and the control of stereotype distortion

We propose a framework for investigating the role of conscious experience in regulating stereotype-based memory distortions. Memory biases are mediated by multiple memory processes, including forms of discriminability and response biases. Different psychological interpretations of these processes depend on how they relate to subjective experiences (e.g., conscious recollection vs. implicit accessibility processes). The ability to control memory distortions, in turn, depends on the psychological meaning attached to these parameters. In Experiment 1 we found that confidence was positively related to discriminability but uncorrelated with stereotype-consistent bias. In Experiment 2 participants were allowed to selectively control when they responded. Because of the asymmetry in monitoring ability, participants were able to increase overall accuracy, but were not able to reduce the stereotype bias. Discussion focuses on the conditions in which subjective experience may provide a valid basis for controlling biases, and when subjective experience may prove deceptive, exacerbating biases.     

Consensus collaboration enhances group and individual recall accuracy

We often remember in groups, yet research on collaborative recall finds "collaborative inhibition": Recalling with others has costs compared to recalling alone. In related paradigms, remembering with others introduces errors into recall. We compared costs and benefits of two collaboration procedures--turn taking and consensus. First, 135 individuals learned a word list and recalled it alone (Recall 1). Then, 45 participants in three-member groups took turns to recall, 45 participants in three-member groups reached a consensus, and 45 participants recalled alone but were analysed as three-member nominal groups (Recall 2). Finally, all participants recalled alone (Recall 3). Both turn-taking and consensus groups demonstrated the usual pattern of costs during collaboration and benefits after collaboration in terms of recall completeness. However, consensus groups, and not turn-taking groups, demonstrated clear benefits in terms of recall accuracy, both during and after collaboration. Consensus groups engaged in beneficial group source-monitoring processes. Our findings challenge assumptions about the negative consequences of social remembering.     

The effects of social pressure on group recall

In two experiments, individual subjects worked in conjunction with two perceived group members to recall six 30-item categorized word lists. The perceived group members' recall levels were manipulated to establish either high or low group standards. After participating in the perceived group, subjects completed a surprise final individual recall test that covered all of the presented material. On the basis of the hypothesis that the subjects' performance would be affected by social pressure, it was predicted that subjects working in high-performing groups would recall more words than subjects working in low-performing groups on both the group recall tests and the final individual recall test. These predicted results were observed. Thus, a complete analysis of the group recall environment should include a consideration of conformity theory whereby subjects' memories can be affected by their group members' output levels.     

Consensus collaboration enhances group and individual recall accuracy

We often remember in groups, yet research on collaborative recall finds “collaborative inhibition”: Recalling with others has costs compared to recalling alone. In related paradigms, remembering with others introduces errors into recall. We compared costs and benefits of two collaboration procedures—turn taking and consensus. First, 135 individuals learned a word list and recalled it alone (Recall 1). Then, 45 participants in three-member groups took turns to recall, 45 participants in three-member groups reached a consensus, and 45 participants recalled alone but were analysed as three-member nominal groups (Recall 2). Finally, all participants recalled alone (Recall 3). Both turn-taking and consensus groups demonstrated the usual pattern of costs during collaboration and benefits after collaboration in terms of recall completeness. However, consensus groups, and not turn-taking groups, demonstrated clear benefits in terms of recall accuracy, both during and after collaboration. Consensus groups engaged in beneficial group source-monitoring processes. Our findings challenge assumptions about the negative consequences of social remembering.     

Memory markers: How consumers recall the duration of experiences

In the present article, we propose a three-stage memory marker model of memory for experience. The human mind generates and encodes “memory markers” of specific episodes, stores them in memory, and after a temporal delay retrieves these markers to reconstruct the experience and make relevant judgments. Rich experiences characterized by vivid stimuli seem to pass by quickly, yet feel longer when recalled after a period of time because the number of retrieved memory markers is large. We also examine situations in which key predictions of the memory marker model can be moderated. A field study and five laboratory experiments were conducted to test various aspects of the memory marker model and provide process support.     

Memory illusions: false recall and recognition in adults with Asperger's syndrome

As persons on the autistic spectrum are known not to use semantic features of word lists to aid recall, they might show diminished susceptibility to illusory memories that typically occur with lists of associated items. Alternatively, since such individuals also have poor source monitoring, they might show greater susceptibility. The authors found that adults with Asperger's syndrome (n = 10) recalled similar proportions of a nonpresented strong associate of the study list items, compared with controls (n = 15). In Experiment 2, rates of true and false recognition of study list associates did not differ significantly between Asperger (n = 10) and control (n = 10) participants. Moreover, the Asperger participants made fewer remember and more know judgments than controls for veridical but not for false recognitions. Thus, deficits found in some aspects of memory in people with Asperger's syndrome do not affect their susceptibility to memory illusions.     

Collaborative false recall in the DRM procedure: Effects of group size and group pressure

Basden, Basden, Thomas, and Souphasith (1998) demonstrated that false recall in collaborative trios is enhanced when group members feel under pressure to output items. In the present study, individuals, pairs, trios, and quartets were presented with lists of words drawn from the Deese-Roediger-McDermott paradigm. Memory was tested under high or low group pressure conditions. It was found that false recall increased in proportion to group size regardless of group pressure, but that groups experiencing the most pressure to output items made a greater number of errors. Furthermore, on a surprise later individual recall test, participants who experienced the most pressure during collaboration retained an equivalent level of critical lures. Collectively these findings demonstrate that group pressure can increase collaborative false recall, and that these false memories can be retained beyond group testing.     

Memory for objects in real scenes: The development of recognition and recall

Subjects examined crowded semirealistic layouts of toy objects, or photographs of these layouts, and then tried to identify added, moved or deleted items. The main study, involving 1st-, 3rd, 6th-graders, and adults, showed that although successful recognition of added items was superior to both recall of deleted items and recognition of moved ones, all three scores improved with age. In addition, false reports of “new” items decreased markedly in the older groups. The results argue against the widely held view that recognition memory undergoes little or no developmental improvement. No significant difference between real layouts and photographs appeared either in the main experiment or in replications involving shorter exposure (Experiment 2) or retarded subjects (Experiment 3).     

Memory and intelligence: Age and ability differences in strategies and organization of recall

Proficiency at organizing information for recall is one aspect of memory functioning which could be expected to be related to intelligence, or general ability. Comparisons of children of average and of superior ability (Kuhlmann-Anderson scores) in a multitrial free-recall learning task confirmed this prediction: Both level of recall and amount of sequential organization were significantly higher for the superior ability groups. Mental age definitions of intelligence imply that equivalent performance by children of different chronological ages will be based on qualitatively similar cognitive processes. This assumption was not confirmed. Age-related changes in mnemonic strategies were not associated with ability-related differences in recall or organization. Some features of memory development are more dependent on age, whereas others are more dependent on ability. The latter may be best explained in terms of production inefficiency (Flavell, 1970).     

Memory distortion and attitude change—Two routes to cognitive balance

We report novel research investigating memory distortion as an alternative route to cognitive balance, comparing it with attitude change as a well‐known balancing mechanism. Participants received statements from multiple communicators about a controversial topic (national pride in Study 1 and climate protection in Study 2) and remembered these statements immediately or 1 week later. This resulted in initially balanced or unbalanced combinations of the liking for individual communicators and the communicators' statements and in subsequent balance increases due to liking change or misremembering of statements. The contribution of memory distortion to balance was significant but weaker and less efficient than that of liking change, and the contributions were empirically independent (i.e., uncorrelated and differentially related to third variables—specifically, memory strength and individual cognitive consistency motivation). They also had a different temporal trajectory (liking change fast and memory distortion slow). We discuss theoretical and practical implications.     

Memory recall in a process control system: a measure of expertise and display effectiveness

Previous research has shown that memory-recall performance is correlated with domain expertise. In this study, a process control system was selected as a vehicle for conducting research on memory recall. The primary purposes of the present work were to determine if the classic expertise effects originally obtained in chess generalize to this novel domain and to evaluate the validity of memory recall as a measure of display effectiveness. Experts and novices viewed dynamic event sequences showing the behavior of a thermal-hydraulic system with two different displays, one that only contained information about the physical components in the system (P) and another that also contained information about higher order functional variables (P+F). There were three types of trials: normal, where the system was operating correctly; fault, where a single fault was introduced; and random, where the system's behavior did not obey physical laws. On each trial, subjects were asked to recall the final state of the system and to diagnose the system state. The P+F display resulted in superior diagnosis performance compared with the P display. With regard to memory, there was some evidence of an interaction between trial type and expertise, with experts outperforming novices but primarily on meaningful trials. In addition, memory for the subset of variables most critical to diagnosis was better with the P+F display than with the P display, thereby indicating that memory recall can be a sensitive measure of display effectiveness. The results also clarify a theoretical problem that has existed for some time in the literature, namely, the conditions under which expertise advantages are to be expected in memory-recall tasks. Collectively, these findings point to the potential benefits of adopting an applied context as a test bed for basic research issues.     

Memory for information about nuclear power: A test of the selective recall hypothesis

To test the selective recall hypothesis, nearly 60 subjects read a report of approximately 500 words presenting both pro- and anti-attitudes to nuclear technology. Two hours prior to this they completed the Nuclear Attitudes Questionnaire. Subjects were given free and cued recall tests approximately five minutes after reading the report. The results partially supported the selective recall hypothesis, paticularly with respect to the free recall of anti-nuclear information. Results are discussed in terms of the recent work on selective memory effects.