False memories and aging

Although memory processes and systems usually operate reliably, they are sometimes prone to distortions and illusions. Here we review evidence indicating that cognitive aging is often associated with increased susceptibility to various kinds of false recollections. Accumulating data indicate that older adults frequently have special difficulties recollecting the source of information, which in turn renders them vulnerable to confusing perceived and imagined experiences, and to related kinds of memory distortions. Evidence from studies of false recall and recognition indicate that older adults are sometimes more likely than younger adults to remember events that never happened, reflecting the influence of indistinct encoding of events and the use of lenient criteria during retrieval. Neuroimaging studies suggest that age-related changes in medial temporal and frontal regions may play a role in the altered functioning of specific encoding and retrieval processes that give rise to memory distortions. Future studies of aging and false memories are likely to provide a promising avenue for illuminating basic mechanisms of memory distortion.     

Memory characteristics of recently imagined events and real events experienced previously

In two experiments, we evaluated the memory characteristics of real and imagined events as they changed over time. Memories of real events were richer than memories of imagined events, and memories of recent events were richer than of events from a week earlier. These differences interacted such that memories of real events performed in week 1 were very similar to memories of events that were imagined in week 2. Source monitoring was tested and implications for the repressed or recovered memory debate are considered.     

Monitoring the future: object and source memory for real and imagined events

In these experiments a memory‐monitoring decision is made, whereby subjects must decide not only whether or not to‐be‐learned stimuli will be remembered—the focus of all of the past research into the Judgement of Learning (JOL)—but also whether they will be able to assess the source of those stimuli, as assessed by a new measure, Judgement of Source (JOS). In Experiment 1 subjects had to judge whether they would remember the occurrence and the source of items that were either seen or imagined. Although seen items were better remembered and sourced than imagined, subjects were unable to predict this outcome: they underestimated their ability to recall seen items and overestimated their ability to recall imagined items. In Experiment 2 subjects had to discriminate between self‐performed or other‐performed enacted or imagined events. We expected that the motor cues associated with overt performance should provide more sensory information than had the visual input in Experiment 1, and this should help subjects to discriminate between real and imagined items. As predicted, JOL magnitude showed that subjects were now able to predict accurately that they would recall more enacted events than imagined events. JOS magnitude showed that subjects incorrectly predicted that self‐enactment would assist source memory compared to imagination. However, it was the source of other‐focused events which was more accurately remembered. The results are discussed in terms of Koriat's (1997) view about cue utility in making JOLs. Copyright © 1999 John Wiley & Sons, Ltd.     

Changes in reality monitoring and episodic memory in early childhood

The purposes of this research were to examine the developmental relation between reality monitoring and episodic memory, to link reality monitoring to autobiographical memory by using extended naturalistic events, and to examine prefrontal functioning as a potential contributor to development in reality monitoring and episodic memory. In Experiment 1, 4-year-olds were worse than 6- or 8-year-olds at reality monitoring after a week delay, despite the fact that they remembered more about real than imagined events and remembered different aspects of each. In Experiments 2 and 3, reality monitoring and episodic memory were evaluated for 4- and 6-year-olds immediately after the events occurred and, in Experiment 3, again after a week delay. Reality monitoring was at higher levels for both age groups, but age differences remained. These data suggest that preschoolers' difficulties with reality monitoring result from a combination of episodic memory deficits and strategic differences. In addition, correlation analyses more directly linked preschoolers' reality monitoring to episodic memory and supported the hypothesis that episodic memory development is related to prefrontal functioning.     

Separating past and future autobiographical events in memory: Evidence for a reality monitoring asymmetry

After thinking about the past and imagining the future, how do people separate these real and imagined events in memory? We had subjects engage in past and future autobiographical elaboration, then later take memory tests that required them to recollect these earlier generated events. In Experiment 1, testing memory for previously generated past or future autobiographical events led to fewer source memory confusions than did an elaborative control task, suggesting that the distinctive features of autobiographical elaboration improved subsequent retrieval monitoring accuracy. In Experiment 2, we directly compared retrieval monitoring accuracy for previously generated past and future autobiographical events and found that subjects made fewer source confusions when searching memory for future events. This asymmetry suggests that the features characterizing future elaborations (e.g., cognitive operations) were used more effectively during reality monitoring than were the features characterizing past elaborations (e.g., perceptual details), and has implications for future-oriented theories of memory.     

The development of metamemory monitoring during retrieval: the case of memory strength and memory absence

This research examined the development of the ability to monitor memory strength and memory absence at retrieval. In two experiments, 7-year-olds, 10-year-olds, and adults enacted and imagined enacting a series of bizarre and common actions. Two weeks later, they completed a memory test in which they were asked to determine whether each action had been enacted, had been imagined, or was novel and to provide a confidence judgment for each response. Results showed that participants across age groups successfully monitored differences in strength between memories for enacted actions and memories for imagined actions. However, compared with 10-year-olds and adults, 7-year-olds exhibited deficits in monitoring of differences in memory strength among imagined actions as well as deficits in monitoring memory absence. Results underscore metamemory developments that have important implications for memory accuracy.     

Age-related deficits in reality monitoring of action memories

The authors describe 3 theoretical accounts of age-related increases in falsely remembering that imagined actions were performed (A. K. Thomas & J. B. Bulevich, 2006). To investigate these accounts and further explore age-related changes in reality monitoring of action memories, the authors used a new paradigm in which actions were (a) imagined only, (b) actually performed, or (c) both imagined and performed. Older adults were more likely than younger adults to misremember the source of imagined-only actions, with older adults more often specifying that the action was imagined and also that it was performed. For both age groups, illusions that the actions were only performed decreased as repetitions of the imagined-only events increased. These patterns suggest that both older and younger adults use qualitative characteristics when making reality-monitoring judgments and that repeated imagination produces richer records of both sensory details and cognitive operations. However, sensory information derived from imagination appears to be more similar to that derived from performance for older adults than for younger adults.     

错觉研究:从狭义到广义的演进

心理学家对错觉现象的关注由来已久,以往的错觉研究大部分关注与知觉过程相联系的错觉。近十几年来,当代错觉研究呈现出新的热点,并从狭义向广义演进。这一研究对象扩展的基础,是错觉现象的本质特征,即认知过程的一致性偏差。广义错觉研究的对象涉及知觉、记忆、思维、推理等各种心理过程。     

A process-dissociation analysis of semantic illusions

We examine semantic illusions from a dual-process perspective according to which the processes that go into failing or succeeding to detect such illusions can be decomposed into controlled processes (checking the facts in the sentence against the information in memory) and automatic processes (the impression of truth that comes from the semantic associations between the elements in the sentence). These processes, we argue, make largely independent contributions to truth judgments about semantic-illusory sentences. The Process Dissociation Procedure was used to obtain estimates of these two kinds of processes. In Study 1, participants judged whether sentences were true or false while under high or low cognitive load. Cognitive load increased the rate of semantic illusions by specifically affecting controlled processing but not automatic processing. In Study 2, a previous paired-associate learning task also increased the rate of semantic illusions, but it did so by specifically affecting automatic processing, not controlled processing.     

Reality monitoring of physically similar and conceptually related objects

Three studies showed that information used in determining a target memory’s source may be derived not only from the target event itself, but also from other nontarget events or memories. Subjects were more likely to claim that an imagined object was perceived when it physically resembled or was conceptually related to another specific item that was actually perceived, relative to when there was no physical resemblance or semantic relation. Furthermore, error rates for imagined items increased with the number of perceived items that they resembled. However, subjects’ orienting task at encoding (perceptually biased or perceptually plus conceptually biased) did not systematically affect error rates. The results indicate that reality monitoring decisions about a target object are influenced by similar physical and conceptual information that was derived from other objects.     

Cross-modal source monitoring confusions between perceived and imagined events

Two experiments tested the prediction based on the source monitoring framework that imagination is most likely to lead to false memories when related perceived events have occurred. Consistent with this, people were more likely to falsely remember seeing events when the events had been both imagined as seen and actually heard than when they were just heard, just visually imagined, or imagined both visually and auditorily. Furthermore, when people considered potential sources for memories or more carefully evaluated features of remembered events, source errors were reduced. On average, misattributed ("false") memories differed in phenomenal qualities from true memories. Taken together, these findings show that as different qualities of mental experience flexibly enter into source attributions, qualities derived from related perceptual events are particularly likely to lead to false claims that imagined events were seen, even when the event involves a primary modality (auditory) different from the target event (visual).     

The role of encoding in reality monitoring: a running memory test with Alzheimer's type dementia

Reality monitoring refers to the discrimination between memories of internal and external events (e.g., Johnson & Raye, 1981). A total of 28 healthy older adults and 28 older adults with Alzheimer's type dementia (DAT) were asked to perform or to imagine performing simple action statements in a running memory test. This task required participants to tell whether the action statement had been carried out or imagined, or whether it was new at unpredictable intervals. The results indicated that older adults with DAT had greater difficulty in reality monitoring than did the healthy control group. The finding is discussed in terms of the role of working memory functions in reality monitoring.     

Source misattributions may increase the accuracy of source judgments

Misattribution of remembered information from one source to another is commonly associated with false memories, but we demonstrate that it also may underlie memories that accord with past events. Participants imagined drawings of objects in four different locations. For each, a drawing of a similarly shaped object was seen in the same location, a different location, or not seen. When tested on memory for objects' origin (seen/imagined) and location, more false "seen" responses, but also more correct location responses, were given to imagined objects if a similar object had been seen, versus not seen, in the same location. We argue that misattribution of feature information (e.g., shape, location) from seen objects to similar imagined ones increased false memories of seeing objects but also increased correct location memories, provided the misattributed location matched the imagined objects' location. Thus, consistent with the source-monitoring framework, imperfect source-attribution processes underlie false and true memories.     

The role of encoding in reality monitoring: A running memory test with Alzheimer's type dementia

Reality monitoring refers to the discrimination between memories of internal and external events (e.g., Johnson & Raye, 1981). A total of 28 healthy older adults and 28 older adults with Alzheimer's type dementia (DAT) were asked to perform or to imagine performing simple action statements in a running memory test. This task required participants to tell whether the action statement had been carried out or imagined, or whether it was new at unpredictable intervals. The results indicated that older adults with DAT had greater difficulty in reality monitoring than did the healthy control group. The finding is discussed in terms of the role of working memory functions in reality monitoring.     

Visual perspective in remembering and episodic future thought

According to the constructive episodic simulation hypothesis, remembering and episodic future thinking are supported by a common set of constructive processes. In the present study, we directly addressed this assertion in the context of third-person perspectives that arise during remembering and episodic future thought. Specifically, we examined the frequency with which participants remembered past events or imagined future events from third-person perspectives. We also examined the different viewpoints from which third-person perspective events were remembered or imagined. Although future events were somewhat more likely to be imagined from a third-person perspective, the spatial viewpoint distributions of third-person perspectives characterizing remembered and imagined events were highly similar. These results suggest that a similar constructive mechanism may be at work when people remember events from a perspective that could not have been experienced in the past and when they imagine events from a perspective that could not be experienced in the future. The findings are discussed in terms of their consistency with—and as extensions of—the constructive episodic simulation hypothesis.     

Remembering the past and imagining the future: examining the consequences of mental time travel on memory

Cognitive, neuropsychological, and neuroimaging evidence suggests that remembering the past and imagining the future rely on overlapping processes in episodic memory. The three experiments reported here examine the consequences of remembering the past and imagining the future on the accessibility of other information in memory. Participants first studied events associated with a specific context and then either (a) retrieved past autobiographical events associated with that same context or (b) imagined future autobiographical events associated with that same context. Replicating and extending evidence of retrieval-induced forgetting, remembering autobiographical events from the past caused participants to forget the related studied events. However, imagining future autobiographical events failed to cause participants to forget the related studied events. These results suggest an important difference in the memorial consequences of remembering and imagining.     

Remembering the past and imagining the future: Examining the consequences of mental time travel on memory

Cognitive, neuropsychological, and neuroimaging evidence suggests that remembering the past and imagining the future rely on overlapping processes in episodic memory. The three experiments reported here examine the consequences of remembering the past and imagining the future on the accessibility of other information in memory. Participants first studied events associated with a specific context and then either (a) retrieved past autobiographical events associated with that same context or (b) imagined future autobiographical events associated with that same context. Replicating and extending evidence of retrieval-induced forgetting, remembering autobiographical events from the past caused participants to forget the related studied events. However, imagining future autobiographical events failed to cause participants to forget the related studied events. These results suggest an important difference in the memorial consequences of remembering and imagining.     

Knowing about not remembering: developmental dissociations in lack‐of‐memory monitoring

Children aged 7 and younger encounter great difficulty in assessing whether lack of memory for an event indicates that the event was not experienced. The present research investigated whether this difficulty results from a general inability to evaluate memory absence or from a specific inability to monitor one feature of memory absence that has been examined in previous studies, namely expected memorability. Seven‐, 8‐ and 9‐year‐olds, and adults (N = 72) enacted, imagined and confabulated about bizarre and common actions. Two weeks later, participants were asked to recognize the actions that had been enacted. Even 7‐year‐olds monitored the relative familiarity of rejected distracters (i.e. reported higher confidence for the rejection of novel versus imagined and confabulated distracters). However, only older children and adults exhibited the ability to monitor expected memorability (e.g. reported higher confidence for the rejection of bizarre versus common distracters). These results suggest that young children exhibit specific, rather than general, deficits in monitoring memory absence, and provide an indication of the specific domains in which lack‐of‐memory monitoring improves during childhood.     

Age-related positivity effects and autobiographical memory detail: Evidence from a past/future source memory task

This study investigated whether the age-related positivity effect strengthens specific event details in autobiographical memory. Participants retrieved past events or imagined future events in response to neutral or emotional cue words. Older adults rated each kind of event more positively than younger adults, demonstrating an age-related positivity effect. We next administered a source memory test. Participants were given the same cue words and tried to retrieve the previously generated event and its source (past or future). Accuracy on this source test should depend on the recollection of specific details about the earlier generated events, providing a more objective measure of those details than subjective ratings. We found that source accuracy was greater for positive than negative future events in both age groups, suggesting that positive future events were more detailed. In contrast, valence did not affect source accuracy for past events in either age group, suggesting that positive and negative past events were equally detailed. Although ageing can bias people to focus on positive aspects of experience, this bias does not appear to strengthen the availability of details for positive relative to negative past events.