The production of false recognition and the associated state of consciousness following encoding in a naturalistic context in aging

Using virtual reality, we implemented a naturalistic variant of the DRM paradigm in young and older adults to evaluate false recall and false recognition. We distinguished false recognition related to the highest semantic association (the critical lures), semantic similarity (i.e. items that belong to the same semantic category), and perceptual similarity (i.e. items that are similar, but not identical in terms of shape or color). The data revealed that younger adults recalled and recognized more correct elements than older adults did while the older adults intruded more critical items than younger adults. Both age groups produced false recognition related to the critical items, followed by perceptually and then semantically related items. False recognitions were highly recollective as they were mainly associated with a sense of remembering, even more so in older adults than in young adults. The decline of executive functions and working memory predicted age-related increases in false memories.     

The effect of warnings on false memories in young and older adults

In the present experiments, we examined adult age differences in the ability to suppress false memories, using the Deese-Roediger-McDermott (DRM) paradigm (Deese, 1959; Roediger & McDermott, 1995). Participants studied lists of words (e.g., bed, rest, awake, etc.), each related to a nonpresented critical lure word (e.g., sleep). Typically, recognition tests reveal false alarms to critical lures at rates comparable to those for hits for studied words. In two experiments, separate groups of young and older adults were unwarned about the false memory effect, warned before studying the lists, or warned after study and before test. Lists were presented at either a slow rate (4 sec/word) or a faster rate (2 sec/word). Young adults were better able to discriminate between studied words and critical lures when warned about the DRM effect either before study or after study but before retrieval, and their performance improved with a slower presentation rate. Older adults were able to discriminate between studied words and critical lures when given warnings before study, but not when given warnings after study but before retrieval. Performance on a working memory capacity measure predicted false recognition following study and retrieval warnings. The results suggest that effective use of warnings to reduce false memories is contingent on the quality and type of encoded information, as well as on whether that information is accessed at retrieval. Furthermore, discriminating between similar sources of activation is dependent on working memory capacity, which declines with advancing age.     

False memories in children and adults: age,distinctiveness, and subjective experience

This study investigated developmental trends associated with the Deese/Roediger-McDermott false-memory effect, the role of distinctive information in false-memory formation, and participants' subjective experience of true and false memories. Children (5- and 7-year-olds) and adults studied lists of semantically associated words. Half of the participants studied words alone, and half studied words accompanied by pictures. There were significant age differences in recall (5-year-olds evinced more false memories than did adults) but not in recognition of critical lures. Distinctive information reduced false memory for all age groups. Younger children provided with distinctive information, and older children and adults regardless of whether they viewed distinctive information, expressed higher levels of confidence in true than in false memories. Source attributions did not significantly differ between true and false memories. Implications for theories of false memory and memory development are discussed.     

Presentation modality effect on false memories in younger and older adults: the use of an inference paradigm

Classically, false memories are studied using the DRM paradigm (Deese, 1959; Roediger & McDermott, 1995), involving use of words lists. The words of each list are linked to a critical word not presented. Participants create a false memory in recognising and/or recalling this critical word. In most cases older adults have more false memories than younger adults in this paradigm. To use less strategy-dependent material, we compared predictive inferences activated during text reading in young and healthy older participants. For example, in the sentence "The fragile porcelain vase was thrown against the wall" the predictive inference was that the vase is broken. After reading or hearing the texts, the participants had false memories in recalling and/or recognising the predictive inferences. Older adults had more false recognitions than younger adults when they read or heard the text. However, the difference did not reach significance with the cued recalled task. It is concluded that, in more ecological situations such as text reading, abilities in older adults can be preserved.     

Phonological false recognition produced by bottom-up automatic activation in young and older people

ABSTRACT

Two experiments explored a new procedure to implicitly induce phonological false memories in young and older people. On the study tasks, half of the words were formed from half of the letters in the alphabet, whereas the remaining words were formed from all the letters in the alphabet. On the recognition tests, there were three types of non-studied new words: critical lures formed from the same half of the letters as the studied words; distractors formed from the other half of the letters not used, and distractors formed from all the letters in the alphabet. In both experiments, the results showed that, in both young and older people, critical lures produced more false recognitions than distractors composed of all the letters in the alphabet, which, in turn, produced more false alarms than distractors composed of the letters not used during the study. These results support the predictions of the activation/monitoring models, which assume that false memories are partly due to activation spreading from items (semantically or phonologically) related to the critical words.     

False memories for a robbery in young and older adults

The aim of the present study was to analyse memory performance in young and older adults based on a robbery scenario. The study examined free recall and the recognition of actions, people and details, as well as the Remember/Know/Guess judgements that accompanied recognition. Recognition was evaluated both immediately and 1 week later, although performance was not affected by the retention interval. In the free recall task, the older adults remembered less information than the younger adults but we found no differences between the two with regard to errors. Participants accepted more false actions, thus achieving higher recognition accuracy for people and details. They also categorized false alarms for actions more often as remember than as know or guess judgements. This pattern of results was more pronounced in the older adults, suggesting that aging is an important factor in false memories for events. Copyright © 2008 John Wiley & Sons, Ltd.     

The effects of emotional content and aging on false memories

After studying a list of words related to a nonpresented lure word, people often falsely recall or recognize the nonpresented lure. Older adults are particularly susceptible to these forms of false memories. The age-related false memory enhancement likely occurs because older adults do not encode, or later retrieve, items in enough detail to allow them to discriminate between presented words and other associated but nonpresented items. Pesta, Murphy, and Sanders (2001) suggested that the emotional salience of the lures may provide distinctiveness, so that individuals would be less likely to endorse an emotional lure as a studied item than to endorse a neutral lure. In the present investigation, young and older adults were less likely to falsely recall or recognize emotional, as compared with neutral, lures. Both age groups appeared capable of using the distinctiveness of the emotional lures to reduce, although not to eliminate, false recall and recognition.     

Effects of repetition and response deadline on item recognition in young and older adults

In the present study, we examined the joint effects of aging, repetition, and response deadline in a plurality discrimination task. Young and older adults studied lists of unrelated singular and plural nouns, with half presented once (weak items) and half presented five times (strong items). Test lists contained old (same) nouns, plurality-reversed nouns (changed lures), and unstudied nouns (new lures), and the participants were asked to respond old only to same items. In Experiment 1, the participants were tested with both short and long deadlines. In Experiment 2, the tests were unpaced. In both experiments, repetition increased hit rates for young and older adults. Young adults tested with a long deadline or no deadline showed invariant (Experiment 1) or reduced (Experiment 2) false alarms to changed lures when the nouns were studied more often. Young adults tested with a short deadline and older adults tested with both long and short deadlines had increased false alarm rates for strong changed lures; without time pressure to respond, older adults did not have a significant increase in false alarms for changed lures. Implications of these results for theories of cognitive aging are explored.     

Remembering Words Never Presented: False Memory Effects in Dementia of the Alzheimer Type

Thirty-five young adults, 35 older adults and 29 individuals with dementia of the Alzheimer’s type studied lists of semantically related words (e.g., thread, pin, sewing) that converged on a non-presented lure (needle). Compared to the young adults, older adults remembered (recall and recognition tests) fewer studied items but falsely remembered more non-presented lures. Memory for studied items was lower in the DAT group compared to normal elders. The DAT group did recall some non-presented lures, although unlike the older adults, recall of non-presented lures was not elevated compared to veridical memory. Similar to the normal elders, the DAT group showed increased susceptibility to false recognition of non-presented lures. Susceptibility to false recognition did not vary as a function of disease severity.     

The effect of forced recall on illusory recollection in younger and older adults

The effect of an initial forced recall test on later recall and recognition tests was examined in younger and older adults. Subjects were presented with categorized word lists and given an initial test under standard cued recall instructions (with a warning against guessing) or forced recall instructions (that required guessing); subjects were later given a cued recall test for the original list items. In 2 experiments, initial forced recall resulted in higher levels of illusory memories on subsequent tests (relative to initial cued recall), especially for older adults. Older adults were more likely to say they remembered rather than knew that forced guesses had occurred in the original study episode. The effect persisted despite a strong warning against making errors in Experiment 2. When a source monitoring test was given, older adults had more difficulty than younger adults in identifying the source of items they had originally produced as guesses. If conditions encourage subjects to guess on a first memory test, they are likely to recollect these guesses as actual memories on later tests. This effect is exaggerated in older adults, probably because of their greater source monitoring difficulties. Both dual process and source monitoring theories provide insight into these findings.     

Inadvertent plagiarism in young and older adults: The role of working memory capacity in reducing memory errors

Two experiments examined inadvertent plagiarism in young and older adults. Young and older adults took turns generating category exemplars in small groups, and after a short retention interval recall was tested and subjects were asked to generate new exemplars (i.e., exemplars not initially generated). When asked to generate new exemplars, older adults were more likely to repeat exemplars that had been generated earlier by others (i.e., generate-new plagiarism). When asked to recall the exemplars they had generated earlier, older adults were more likely to claim that they had generated exemplars that had been generated by others (i.e., recall-own plagiarism), and were also more likely to falsely recall exemplars that had not been generated at all. There were no age differences in confidence for items that were plagiarized on the generate-new task. Hierarchical regression analyses indicated that age differences in generate-new plagiarism and false recall were entirely mediated by measures of episodic recall and working memory capacity. We conclude that inadvertent plagiarism errors result from the failure of systematic decision processes, and that controlled attention is important for avoiding memory errors.     

Conjunction errors in recognition memory: modality-free errors for older adults but not for young adults

A dual-process theory of memory was applied to processes in normal aging, with a focus on recognition errors in the feature-conjunction paradigm (i.e., false recognition of blackbird after studying parent words blackmail and/or jailbird). Study repetition was manipulated so that some parent words occurred once and others occurred three times. Age-related differences on hit scores occurred for two experiments. The results for feature and conjunction conditions showed repetition effects but no age-related differences when participants were uninformed of the lures (Experiment 1). However, age-related differences emerged when the retrieval of modality source information created a way to evade conjunction errors (Experiment 2). In the second experiment, study repetition decreased errors for the young adults but increased errors for the older adults, and young adults were better able than older adults to avoid conjunction errors when the parent words had been repeated. For older adults, the conjunction errors were modality-free. The results provide additional evidence that older adults experience difficulty in recollecting aspects of a study experience, and the results from groups of young adults required to respond quickly on the tests provide converging evidence for this conclusion.     

Effects of repetition on age differences in associative recognition

The study reported here examined the effect of repetition on age differences in associative recognition using a paradigm designed to encourage recollection at test. Young and older adults studied lists of unrelated word pairs presented one, two, four, or eight times. Test lists contained old (intact) pairs, pairs consisting of old words that had been studied with other partners (rearranged lures), and pairs consisting of two unstudied words (new lures). Participants gave old/new responses and then indicated whether their responses were based on details that they could recollect or on familiarity. Older adults exhibited an ironic effect of repetition—an increase in false alarms on rearranged lures with more study opportunities—whereas young adults did not. Older adults also claimed to recall details of the study episode for rearranged lures whose constituent words were presented more frequently, but this was not true for young adults. Although both young and older adults said that they based correct rejections of rearranged lures on memory for details of the study episode, this effect was stronger for young adults. The observed age differences are consistent with older adults having reduced use of recollection in associative recognition tasks.     

Source attributions and false memories: a test of the demand characteristics account

When lists of related words are presented to subjects, they sometimes recall or recognize nonpresented words related to those lists (critical lures). In fact, subjects sometimes claim to remember which of two speakers said the critical lures. We examined whether this finding could be accounted for by demand characteristics. If subjects’ willingness to make source attributions to critical lures reflects experimental demand, one would predict that subjects should be willing to change and should have little confidence in these attributions. Subjects made more attributions, were less likely to change their attributions, and were more confident in their attributions for critical lures than for unrelated distractors. Subjects had even more confidence in the attributions that they made for words that had actually been presented, and they were even less likely to change these attributions. These findings suggest that false memories are quite compelling but that they are also subtly different from true memories.     

Effects of repetition and response deadline on associative recognition in young and older adults

The present study examined the joint effects of repetition and response deadline on associative recognition in older adults. Young and older adults studied lists of unrelated word pairs, half presented once (weak pairs) and half presented four times (strong pairs). Test lists contained old (intact) pairs, pairs consisting of old words that had been studied with other partners (rearranged lures), and unstudied pairs (new lures), and participants were asked to respond "old" only to intact pairs. In Experiment 1, participants were tested with both short and long deadlines. In Experiment 2, the tests were unpaced. In both experiments, repetition increased hit rates for young and older adults. Young adults tested with a long deadline showed reduced (Experiment 1) or invariant (Experiment 2) false alarms to rearranged lures when word pairs were studied more often. Young adults tested with a short deadline and older adults tested under all conditions had increased false alarm rates forstrong rearranged pairs. Implications of these results for theories of associative recognition and cognitive aging are explored.     

Variations in processing resources and resistance to false memories in younger and older adults

The influence of available processing resources on the resistance to false memories (FMs) for lists of semantically related items associated with a non-presented critical lure was examined in younger and older adults. Reducing the available resources at encoding in younger adults (Experiments 1 and 2) led to a performance similar to that of older adults (i.e., higher rates of FMs in addition to reduced rates of correct recall). However, increasing the available resources (Experiments 2 and 3) led to improvements in the rates of correct recall in both age groups and decreased the probability of FMs in younger adults, although warnings had to be added in older adults to obtain similar effects on FMs. Parallel influences on a post-recall test asking participants to report items that they had thought of but did not recall were also found. The influence of available cognitive resources for memory accuracy is also discussed with respect to activation-monitoring (e.g., McDermott & Watson, 2001) and fuzzy-trace (e.g., Brainerd & Reyna, 2002) accounts of age-related increased in false memories.     

Two types of recollection-based monitoring in younger and older adults: Recall-to-reject and the distinctiveness heuristic

People often use recollection to avoid false memories. At least two types of recollection-based monitoring processes can be identified in the literature. Recall-to-reject is based on the recall of logically inconsistent information (which disqualifies the false event from having occurred), whereas the distinctiveness heuristic is based on the failure to recall to-be-expected information (which is diagnostic of non-occurrence). We attempted to investigate these hypothetical monitoring processes in a single task, as a first step at delineating the functional relationship between them. By design, participants could reject familiar lures by (1) recalling them from a to-be-excluded list (recall-to-reject) or (2) realising the absence of expected picture recollections (the distinctiveness heuristic). Both manipulations reduced false recognition in young adults, suggesting that these two types of monitoring were deployed on the same test. In contrast, older adults had limited success in reducing false recognition with either manipulation, indicating deficits in recollection-based monitoring processes. Depending on how a retrieval task is structured, attempts to use one monitoring process might interfere with another, especially in older adults.     

A brighter side to memory illusions: false memories prime children's and adults' insight-based problem solving

Can false memories have a positive consequence on human cognition? In two experiments, we investigated whether false memories could prime insight problem-solving tasks. Children and adults were asked to solve compound remote associate task (CRAT) problems, half of which had been primed by the presentation of Deese/Roediger-McDermott (DRM) lists whose critical lures were also the solutions to the problems. In Experiment 1, the results showed that regardless of age, when the critical lure was falsely recalled, CRAT problems were solved more often and significantly faster than problems that were not primed by a DRM list. When the critical lure was not falsely recalled, CRAT problem solution rates and times were no different from when there was no DRM priming. In Experiment 2, without an intervening recall test, children and adults still exhibited higher solution rates and faster solution times to CRAT problems that were primed than to those that were not primed. This latter result shows that priming occurred as a result of false memory generation at encoding and not at retrieval during the recall test. Together, these findings demonstrate that when false memories are generated at encoding, they can prime solutions to insight-based problems in both children and adults.     

Memory for a dialectical and a nondialectical prose passage in young and older adults

Age differences in adults' processing of a dialectical or nondialectical prose passage were explored. Twenty young and 20 older adults read a dialectical or mechanistic passage and were tested for free recall and recognition after a 30-min delay (filled with vocabulary and paradigm belief scale). Older (vs. young) adults had significantly lower formistic and mechanistic scores and showed greater relative preference for relativistic and dialectical beliefs (paradigm scale). There were no age differences in amount of free recall or number of correct responses (hits) on recognition, but older adults produced more spontaneous dialectical distortions in recall of the mechanistic passage and more paradigm-congruent false alarms on recognition. There was also a move from absolute toward dialectical thinking on the paradigm scale and, among males, on the recognition measure. Dialectical scores (paradigm scale) were positively correlated, and mechanistic scores negatively correlated, with number of dialectical distortions on free recall (mechanistic passage), while dialectical scores were positively correlated with number of dialectical false alarms (dialectical passage).     

The benefits and costs of repeated memory tests for young and older adults

Repeated and prolonged searches of memory can lead to an increase in how much is recalled, but they can also lead to memory errors. These 3 experiments addressed the costs and benefits of repeated and prolonged memory tests for both young and older adults. Participants saw and imagined pictures of objects, some of which were physically or conceptually similar, and then took a series of repeated or prolonged recall tests. Both young and older adults recalled more on later tests than on earlier ones, though the increase was less marked for older adults. In addition, despite recalling less than did young adults, older adults made more similarity-based source misattributions (i.e., claiming an imagined item was seen if it was physically or conceptually similar to a seen item). Similar patterns of fewer benefits and more costs for older adults were seen on both free and forced recall tests and on timed and self-paced tests. Findings are interpreted in terms of age-related differences in binding processes.