Is there something special about memory for internally generated information?

In two experiments, the number of times subjects saw and generated words was varied, and then half the subjects were asked to judge presentation frequency and half were asked to judge generation frequency. People were more sensitive to the relative frequency of internally generated, compared with externally generated, events. Also, judgments of internal events were less affected by whether or not the subjects were given a restricted range of numbers for their judgments, and internally generated events produced more confusion in estimating external event frequency than vice versa. The results are discussed in terms of potential differences in the characteristics of memory representations originating in external, compared with internal, events and the way these might interact with the judgment process.     

The consequences of encoding information on the maintenance of internally generated images and thoughts: the role of meaning complexes

Three experiments investigated the hypothesis that internally generated images and thoughts were driven by meaning complexes, a construct which reflects a synthesis of semantic meaning and personal salience (Klinger, 1999). Experiments 1 and 2 contrasted the mutual inhibition between encoding words and non-words on: (i) the frequency that thoughts and images unrelated to the task (task unrelated thought, TUT) were experienced (Experiment 1) and (ii) on the intensity of images generated from long-term memory and maintained under dual task conditions, which whilst familiar were not of particular personal salience (Experiment 2). Experiment 3 examined the physiological arousal associated with the experience of TUT in a semantic encoding task. Evidence suggested that, in general, internally generated images and thoughts, irrespective of the personal salience, were suppressed by the co-ordination of information in working memory. In addition, only the experience of spontaneous images and thoughts of personal salience (TUT, Experiments 1 and 3) interfered reliably with the encoding/retrieval of semantic information from memory. Finally, in Experiment 3, physiological arousal, as indexed by mean heart rate, was associated with a high frequency of TUT. The results of all three experiments support the notion that the maintenance of spontaneously occurring images and thoughts is simultaneously influenced by both the semantic content and the personal salience of the information held in working memory.     

Reconstructive memory in the dating of personal and public news events

Two experiments investigated memory for the dates of events selected and recorded by subjects in diaries. In Experiment 1, personal events and public news events were compared, with retention time varying from 1 week up to 9 months. It was found that the day of the week was more accurately identified for personal events than for news events, that day-of-the-week (DOW) accuracy did not decrease with increasing retention time, and that memory of the personal context of both event types was more important for DOW accuracy than was memory of the core of the events. These results support our view that memory of the day of the week is mainly reconstructed by reference to a temporal week schema based on personal experiences, and that the relation of news events to the week schema is mediated by memory of personal context. The distribution of DOW errors was modeled as the outcome of a process of guessing constrained by subdivisions of the week schema, without assuming any special temporal memory trace. In Experiment 2, the model was shown to fit independently collected data from a different subject pool and country equally well.     

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.     

Are there developmental differences in reality-monitoring?

The question addressed by the present experiment is whether the ability to distinguish between veridical and imaginal memory representations changes with age. Second-grade, fourth-grade, and sixth grade children (8, 10, and 12 years old) and college students were shown pictures of familiar objects. Each picture was presented one, two, or three times and, interspersed with these presentations, subjects were asked to imagine each picture zero, one, or three times. Subsequently they were asked to judge the presentation frequency of each picture. For all groups, imagining the pictures resulted in inflated estimates of event frequency. However, contrary to the idea that children have a particularly difficult time discriminating externally generated from internally generated memories, one analysis indicated adults were actually somewhat more affected than children by the imagination trials.     

The effect of attending to feeling on memory for internally generated stimuli

The present experiments examined the effects of self-focus, as produced by focusing on feelings, on memory. In an initial experiment subjects did complex mental arithmetic significantly faster after self-focus. Because complex mental addition involves internally generated stimuli, the remaining experiments compared the effects, on memory, of self-focus on internally generated stimuli to the effect of self-focus on stimuli supplied by the experimenter. In a second experiment, self-focus facilitated memory for digits recalled in reverse order but not for digits when recalled in the given order. In a third experiment, self-focus facilitated the memory for the classification of digits but not for the digits themselves. In a fourth and fifth experiment, self-focus aided memory for classification of objects into categories such as small, medium, or large but did not aid memory for the objects themselves. In general, improved performance due to feeling focus was attributed to the role that self-focus may play in increasing attention to internally generated stimuli.     

Memory for internally generated words in Alzheimer-type dementia: breakdown in encoding and semantic memory

The "generation effect" is a phenomenon in which words that are generated by the subject are remembered better than words which are read. The present experiments examined this effect in patients with mild-to-moderate dementia of the Alzheimer type (DAT), healthy elderly adults, and young adults under a variety of different encoding and retrieval conditions. Experiment 1 employed an intentional learning task with multiple study/test trials using the same list of words. While both the young and elderly adults exhibited higher recall for internally generated words than read words, the DAT patients failed to demonstrate the effect even after repeated exposures to the same stimulus list. Experiment 2 replicated this same pattern of results using an incidental learning paradigm with both recall and recognition tests. Various explanations as to why the DAT patients failed to show the generation effect were discussed with particular emphasis placed on the role of semantic memory and encoding failure.     

High emotional arousal and failures in reality monitoring: Pathways to auditory hallucinations in non‐psychotic children?

Recent research has confirmed the presence of auditory hallucinations in non‐psychotic children, with this research also suggesting that such hallucinations may be more common than previously thought. While auditory hallucinations in children have frequently been associated with high levels of emotional stress, there is still a poor understanding of how this stress may precipitate hallucinations, and why some children experience hallucinations while others seem not to. The current study assessed the association between high levels of trauma symptomatology, anxiety and depression, and the presence of hallucinations against matched controls. Results indicated that hallucinating children had significantly higher mean anxiety, depression and, in particular, re‐experiencing scores than did the children in the control group. These results were examined within the framework of reality monitoring, that is, the ability to distinguish between externally or internally generated sources of information. The notion of high levels of emotional distress decreasing the efficiency of reality monitoring and leading to the possibility of confusion between internally and externally generated stimuli was discussed, with the conclusion advanced that the misattribution of an externally generated source – either held as a memory or as a traumatic re‐experiencing – as an internally generated one, underlies hallucinatory experiences.     

Memory for traumatic events

This research compares memory for traumatic events with memory for non-traumatic versions of the same event. In Experiment 1, subjects watched an event depicted in slides while focusing and rehearsing the central detail of each slide. They were tested after a short or a longer retention interval (20 min or 2 weeks). Subjects who watched the traumatic version were better able to recall the central details that they had rehearsed, but were less well able to recognize the specific slides that they saw. Better recall for the traumatic group did not occur because the words used to describe the recalled details were inherently more memorable, as shown in Experiment 2. In Experiment 3, subjects watched either a traumatic or non-traumatic version of a filmed event and about 6 months later they were asked to remember the essence of the film. Subjects who saw the traumatic version were better able to recall the essence of the film. A similar finding was obtained with a group of subjects from Experiment 1 who were also contacted about 6 months after their initial participation. These results suggest that some information (the essence, the theme) of a traumatic event might be relatively well retained in memory, while memory is impaired for many of the specific, and especially peripheral, details.     

Inside and outside the mind: The effects of age,organization, and access to external sources on retrieval of life events

Older and middle-aged adults recorded autobiographical events on one of two forms of a Personal History Calendar, organized either by year-of-occurrence or by life event category. In Experiment 1, calendars were completed in three stages. In Stage 1, subjects completed the calendar from memory (half were told to expect Stage 2). In Stage 2, each subject reviewed Stage 1 responses with his/her spouse. In Stage 3, subjects could consult external sources. The Event Calendar yielded the most complete Stage 1 recall only for the older group. The Year Calendar generally yielded the greatest number of events, but only when members of a couple did not expect Stage 2. In Experiment 2, subjects completed the calendars in one stage, during which they had access to external sources. The Year Calendar elicited more events than the Event Calendar, but only for older subjects. The results are discussed in terms of retrieval processes in autobiographical memory, and implicatons for survey-based research.     

Effects of type of cognitive demand on bilateral advantage in interhemispheric processing

The relationship between cognitive task demand and effect of bilateral advantage (BLA) was examined. In Experiment 1, the task demand based upon visual stimulus complexity was manipulated. One-digit and two-digit numbers were presented in the left, right or both visual fields tachistoscopically and subjects were requested to identify the numbers. The results showed no BLA, although a right visual field advantage was demonstrated. In Experiment 2, cognitive demand in terms of memory was manipulated. Subjects were asked to recall one-digit numbers that were presented successively once, three and five times in the left, right or the both visual fields. The results did not show any sign of BLA in the recall of numbers. In Experiment 3, a greater memory load task was given than that in Experiment 2, where two-digit numbers were presented successively (once, three and five times). Subjects were asked to recall the numbers. The results showed a significant BLA in the recall of numbers, i.e., the correct numbers in the correct temporal positions. These results strongly suggest that a benefit of redundant bilateral visual fields presentation is shown only in a highly cognitively demanding task, especially when it involves phonological memory loads.     

Aging and effect of predictability on reality monitoring

This study compared the direction of source confusions and the effect of predictability on reality monitoring for internally generated information and externally derived information in younger (mean age 19-25) and older (mean age 70-85) adults. Participants were invited to listen to the conclusions of simple stories or to generate and imagine them. Conclusions could be either highly predictable (Experiment 1) or unpredictable (Experiment 2). The change in predictability produced changes in the direction of source confusions only in older adults. When a story ended in a predictable way, older adults attributed to imagination conclusions that were actually perceived, whereas the pattern of confusions tended to reverse with unpredictable stories.     

Tunnel memories for autobiographical events: central details are remembered more frequently from shocking than from happy experiences

In three experiments, undergraduates recorded as many details as possible for autobiographical memories of highly positive and highly negative events in their lives. Experiment 1 replicated earlier findings for memories of highly negative events: Central details were recorded more frequently than peripheral details, and a weak correlation was found between emotional intensity and number of central details. In Experiment 2, undergraduates recorded details of memories of both their happiest and their most shocking events. Central details dominated over peripheral details only in memories of shocking events. This finding was replicated in Experiment 3. Recording memory details affected the participants' moods and generated a mood congruence effect in a subsequent recall of word-cued memories. The finding suggest that tunnel memories--enhanced memory for the central details of an event--are limited to emotionally negative memories. The findings contradict expectations derived from the notion of repression.     

Task switching based on externally presented versus internally generated information

A number of observations from the task switching literature suggest that task preparation based on internally generated knowledge is less efficient than task preparation based on externally presented information. In the present study, we investigated task switching based on internally generated versus externally presented information and additionally varied the reliability of foreknowledge. Source and reliability of foreknowledge were varied between groups of participants. With reliable foreknowledge, the relevant task always conformed to foreknowledge, even when the features of the imperative stimulus called for an alternative task. With unreliable foreknowledge, the relevant task was determined by the imperative stimulus and foreknowledge was sometimes misleading. Apart from measuring switch costs, we examined the effectiveness of establishing a task set by measuring interference exerted by conflicting stimuli (conditions with reliable foreknowledge) or misled expectancies (conditions with unreliable foreknowledge). In terms of switch costs, we observed a slight superiority of externally presented over internally generated information when foreknowledge was reliable, but this relationship strongly reversed with unreliable foreknowledge. This conclusion was corroborated by observations regarding the effectiveness of task-set establishment in terms of proneness to interference.

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Children's recall of contextually integrable and nonintegrable episodic events

The hypothesis of this study is that children's deficiency in encoding input information may be attributed partially to a failure to fully integrate target and contextual information. Second and fourth grade children and college adults were shown sentences varying in internal integrability in a cued recall task for target nouns in the sentences. The sentences were internally semantically Congruous, Incongruous, or Anomalous. In acquisition, the subjects were told either to read the sentences (Read Encoding) or to rate the likelihood of the occurrence of the sentential event (Integration Encoding). The results showed large developmental differences in both levels of recall and the Congruity effect (superior recall for the Congruous relative to the Anomalous sentences) in the Read condition. These differences were minimized in the Integration condition. These patterns suggest young children are deficient in the contextual integration of episodic events, and, as a result, make inefficient use of semantic information in the encoding of input information.     

The generation effect: a test between single- and multifactor theories

Single- and multifactor accounts of the generation effect (better memory for internally generated items than for externally presented items) were tested. Single-factor theories suggest that generation induces either stimulus-response relational processing or response-oriented processing. Multifactor theories suggest that generation induces both types of processing. In the first three experiments subjects either read or generated responses, and the degree of categorical structure within the list was manipulated. When categorical structure was minimal, large generation effects were observed for free recall and recognition, but not for cued recall. When categorical structure was high, however, a generation effect was observed for cued recall but not for recognition or free recall. A fourth experiment was performed to eliminate an uninteresting interpretation of the results. It is argued that a multifactor account is needed to explain these findings.     

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.     

Biased retellings of events yield biased memories

When people retell events, they take different perspectives for different audiences and purposes. In four experiments, we examined the effects of this postevent reorganization of events on memory for the original events. In each experiment, participants read a story, wrote a biased letter about one of the story characters, and later remembered the original story. Participants' letters contained more story details and more elaborations relevant to the purpose of their retellings. More importantly, the letter perspective affected the amount of information recalled (Experiments 1, 3, and 4) and the direction of the errors in recall (Experiments 1 and 3) and recognition (Experiment 2). Selective rehearsal plays an important role in these bias effects: retelling involves selectively retrieving and using story information, with consequent differences in memory. However, biased memory occurred even when the biased letters contained little, if any, specific information (Experiment 4) or contained the same amount and kinds of story information as a neutral control condition (Experiment 3). Biased memory is a consequence of the reorganizing schema guiding the retelling perspective, in addition to the effects of rehearsing specific information in retelling.     

The interaction of pronunciation rules and lexical representations in reading aloud

Two experiments examined the role of pronunciation rules and of lexical information in pronouncing letter strings. In Experiment 1, subjects pronounced pseudowords varying in the strength of the rules needed to pronounce them, as well as in the availability of a lexical model. In Experiment 2, the stimuli were words varying in rule strength and in usage frequency. The pronunciation times from both experiments displayed an interaction between rules and lexical information: When the rules necessary were strong, the relative availability of lexical information was less important than when the rules were weak. The results were discussed with respect to both traditional dual-process models of pronunciation and models proposing the use of lexical analogies.     

Memory for frequency of hearing popular songs

In two experiments college students were asked to provide situational frequency estimates of 10-s excerpts from rock songs. In both experiments familiarity of the musical selections heard one, two, three, or four times was varied. In Experiment 2 the nature of instructions given to subjects prior to presentation of the musical excerpts was also manipulated. Across both experiments subjects' estimates were less accurate for unfamiliar than for familiar rock music. In Experiment 2 instructions to remember frequency, as well as general memory instructions, resulted in better memory for presentation frequency than did instructions to "ignore" music while working on math problems. Memory for situational frequency was also related to knowledge of rock music as defined by subjects' ability to identify the titles and artists of the presented songs. The present pattern of results with popular music is viewed as similar to that obtained in experiments investigating memory for frequency of verbal stimuli. Although providing support for an automatic processing view of frequency encoding, the results also implicate meaningful elaboration of stimuli as an important determinant of memory for frequency of events.