A jigsaw puzzle theory of memory

The principal novel feature of this paper is the notion that a coherent memory can be synthesised from a set of partially coherent memory fragments by maximising a particular function, Harmony (Smolensky, 1986). The appeal of Harmony is that it fulfils two functions: it is at the heart of the synthesis algorithm and it provides a natural measure for “feeling-of-knowing”. The model is applied to feeling-of-knowing data, flashbulb memories, flashbacks, repression, dissociation, memory stability across repeated recalls, and the effects of cue size on retrieval.     

Accuracy of feeling-of-knowing judgments for predicting perceptual identification and relearning

The feeding of knowing refers to predictions about subsequent memory performance on previously nonrecalled items. The most frequently investigated type of subsequent performance has been recognition. The present research explored predictive accuracy with two new feeling-of-knowing criterion tests (in addition to recognition): relearning and perceptual identification. In two experiments, people attempted to recall the answers to general-information questions such as, "What is the capital of Australia?", then made feeling-of-knowing predictions for all nonrecalled answers, and finally had a criterion test to assess the accuracy of the feeling-of-knowing predictions. Experiment 1 demonstrated that perceptual identification can be employed successfully as a criterion test for the feeling of knowing. This opens a new way for metamemory research via perception. Moreover, the feeling-of-knowing accuracy for predicting perceptual identification was not significantly correlated with the feeling-of-knowing accuracy for predicting recognition, in accord with the idea that these two tests assess memory differently. Experiment 2 demonstrated that relearning performance can also be predicted by feeling-of-knowing judgments. Both experiments showed that there is a positive relationship between the feeling of knowing and the amount of time elapsing before a memory search is terminated during recall. Further analyses showed that this relationship is substantial for nonrecalled items for which the person did not guess an answer (omission errors), but the relationship is null or negative for nonrecalled items that the person guessed incorrectly (commission errors). Several theoretical mechanisms that may underlie the feeling of knowing are proposed.     

A comparison of three predictors of an individual's memory performance: the individual's feeling of knowing versus the normative feeling of knowing versus base-rate item difficulty

Distinctions are drawn between different predictors of an individual's memory performance, with emphasis on the notion of privileged access to idiosyncratic knowledge. Research is reported in which undergraduates attempted to recall the answers to general-information questions, then made feeling-of-knowing judgments on nonrecalled items, and subsequently had a criterion test (relearning, perceptual identification, or one of two versions of recognition). For predicting an individual's criterion performance, the individual's own feeling-of-knowing predictions were intermediate between two kinds of normative predictions: The individual's feeling-of-knowing predictions were more accurate than predictions derived from normative feeling-of-knowing ratings but were less accurate than predictions derived from base-rate item difficulty (normative probabilities of correct recall). Subsidiary analyses showed that factors other than unreliability are responsible for the partial inaccuracy of the individual's feeling of knowing. Ramifications are discussed for possible ways to improve the accuracy of an individual's feeling-of-knowing predictions.     

The relation between feelings of knowing and the number of neighboring concepts linked to the test cue

We investigated whether feeling-of-knowing judgments are influenced by the number of different neighboring concepts linked to the test cue in long-term memory as measured using association norms. The purpose was to evaluate contrasting predictions made by the partial-retrieval hypothesis and the competition hypothesis. The partial-retrieval hypothesis assumes the more neighboring concepts activated by the test cue, the higher the feeling of knowing. In contrast, the competition hypothesis assumes that feelings of knowing are sensitive to competition between neighboring concepts, and it predicts that the fewer neighboring concepts activated by the cue, the higher the feeling of knowing. The findings were compatible with the competition hypothesis showing that both feeling-of-knowing and prediction-of-knowing ratings always were higher, the fewer different concepts were linked to the test cue. We obtained an identical pattern of results using different kinds of cues including taxonomic category names, ending sounds, and meaningfully related associates. We consider different ways that these findings could be reconciled with the partial-retrieval hypothesis, and we also discuss implications for other explanations of feeling-of-knowing effects.     

Memory and metamemory: a study of the feeling-of-knowing phenomenon in amnesic patients

Accuracy of the feeling of knowing was tested in patients with Korsakoff's syndrome, patients prescribed electroconvulsive therapy, four other cases of amnesia, and control subjects. In Experiment 1, we tested feeling-of-knowing accuracy for the answers to general information questions that could not be recalled. Subjects were asked to rank nonrecalled questions in terms of how likely they thought they would be able to recognize the answers and were then given a recognition test for these items. Only patients with Korsakoff's syndrome were impaired in making feeling-of-knowing predictions. The other amnesic patients were as accurate as control subjects in their feeling-of-knowing predictions. In Experiment 2, we replicated these findings in a sentence memory paradigm that tested newly learned information. The results showed that impaired metamemory is not an obligatory feature of amnesia, because amnesia can occur without detectable metamemory deficits. The impaired metamemory exhibited by patients with Korsakoff's syndrome reflects a cognitive impairment that is not typically observed in other forms of amnesia.     

Memory and metamemory in obsessive-compulsive disorder

Studies on the link between checking and memory problems have produced equivocal results regarding a general memory deficit in patients with obsessive-compulsive disorder and subclinical checkers. However, there is clear and consistent evidence that patients with obsessive-compulsive disorder (OCD) show lack of confidence in their memory performance. The purpose of the present study was to investigate memory and metamemory performance (feeling-of-knowing judgments) for neutral and threat-related material in three groups: OCD patients (OCs), subclinical checkers (SCs), and normal controls (NCs). Participants studied a list of neutral and threat word pairs. After an initial cued-recall test, they provided feeling-of-knowing (FOK) judgments for unrecalled word pairs, followed by a recognition test. The results showed that OCs but not SCs were impaired in both recall and recognition compared to NCs. OCs were also less confident about their future memory performance than the other two groups, as reflected in their lower FOK ratings. Moreover, FOK judgments of the OCs were not reliable predictors of their recognition performance. Finally, neither OCs nor SCs showed any evidence of memory bias for threat-relevant information. The results support the idea of a general memory and a metamemory deficit in OCs.     

Two dissociable aspects of feeling-of-knowing: knowing that you know and knowing that you do not know

Feeling-of-knowing judgement is traditionally regarded as a unitary cognitive process. However, recent research suggests that knowing that you know (positive feeling-of-knowing) and knowing that you do not know (negative feeling-of-knowing) have different neural substrates (Luo, Niki, Ying, & Luo, 2004). In the present study, we used a paradigm adapted from Koriat and Levy-Sadot (2001) to examine whether positive feeling-of-knowing and negative feeling-of-knowing were mediated by distinct cognitive processes. We found that positive and negative feeling-of-knowing were dissociated during immediate feeling-of-knowing judgements (i.e., preliminary feeling-of-knowing) and delayed feeling-of-knowing judgements (i.e., postretrieval feeling-of-knowing). At the judgement intervals, positive feeling-of-knowing was based on partial recovery of the nonrecalled targets, whereas negative feeling-of-knowing was determined by familiarity with the retrieval cues. Our results suggest that feeling-of-knowing is a heterogeneous process.     

Memory awareness disruptions in amnestic mild cognitive impairment: comparison of multiple awareness types for verbal and visuospatial material

Successful memory is normally accompanied by explicit awareness of retrieval and confidence in the accuracy of the retrieval product. Prior findings suggest that these features of metamemory can be dissociated from retrieval accuracy in Amnestic Mild Cognitive Impairment (aMCI). However, the literature on this question contains variable and conflicting results, likely because of differences in experimental conditions. We sought to systematically evaluate memory awareness disruptions in aMCI using multiple measures and stimulus formats within the same individuals. Memory awareness was tested with global predictions and postdictions, judgments of learning, confidence level ratings, and modified feeling-of-knowing ratings in tasks of visuospatial and verbal memory. These tests were administered to 14 individuals with aMCI and 15 healthy, age-matched controls. Memory awareness accuracy was calculated as the correspondence between subjective judgments and memory performance.Individuals with aMCI demonstrated impaired global and trial-level retrospective task awareness for visuospatial and verbal stimuli. Additionally, modified feeling-of-knowing awareness was impaired selectively for verbal stimuli. Statistical effect sizes for global awareness impairments were comparable to impairments in several objective neuropsychological memory assessments.Memory awareness (metamemory) disruptions in aMCI were most evident for a subset of subjective judgment types and task input modalities. These findings advance understanding of the nature of memory impairments in aMCI and support the utility of incorporating memory awareness testing to better characterize memory integrity in older adults.     

Effects of alcohol intoxication on metamemory and on retrieval from long-term memory

In a balanced-placebo design, people expected either an alcohol drink or placebo drink and consumed either alcohol (1 ml/kg) or placebo. Shortly thereafter, each person attempted to recall the answers to general-information questions (e.g., "What is the capital of Chile?"), made confidence judgments about the accuracy of recall, made feeling-of-knowing judgments on all nonrecalled items, and received a recognition test. Unanticipated outcomes included: Alcohol intoxication significantly hindered recall from long-term memory, contrary to previous conclusions that alcohol does not affect retrieval; people's expectancy of alcohol had no significant effect on memory or metamemory performance, contrary to its established effects on other kinds of performance; and alcohol intoxication produced no significant overconfidence in judgments about recall or in feeling-of-knowing judgments, contrary to the overconfidence produced in other kinds of judgments such as an intoxicated person's assessment of his driving ability. This last outcome implies that alcohol intoxication does not produce a general lowering of the threshold for confidence but rather has effects that are situation specific.     

Diminished episodic memory awareness in older adults: evidence from feeling-of-knowing and recollection

The ability to reflect on and monitor memory processes is one of the most investigated metamemory functions, and one of the important ways consciousnesses interacts with memory. The feeling-of-knowing (FOK) is one task used to evaluate individual's capacity to monitor their memory. We examined this reflective function of metacognition in older adults. We explored the contribution of metacognition to episodic memory impairment, in relation to the idea that older adults show a reduction in memory awareness characteristic of episodic memory. A first experiment showed that age affects the accuracy of FOK when predictions are made on an episodic memory task but not on a semantic memory task, suggesting a particular role for episodic memory awareness in metacognitive evaluations. A second experiment showed that the age-difference in episodic FOK accuracy was removed if one took into account subjective reports of memory awareness, or recollection. We argue that the FOK deficit specific to episodic memory is based on a lack of memory awareness manifest as a recollection deficit.     

The use of cue familiarity during retrieval failure is affected by past versus future orientation

Cue familiarity that is brought on by cue resemblance to memory representations is useful for judging the likelihood of a past occurrence with an item that fails to actually be retrieved from memory. The present study examined the extent to which this type of resemblance-based cue familiarity is used in future-oriented judgments made during retrieval failure. Cue familiarity was manipulated using a previously-established method of creating differing degrees of feature overlap between the cue and studied items in memory, and the primary interest was in how these varying degrees of cue familiarity would influence future-oriented feeling-of-knowing (FOK) judgments given in instances of cued recall failure. The present results suggest that participants do use increases in resemblance-based cue familiarity to infer an increased likelihood of future recognition of an unretrieved target, but not to the extent that they use it to infer an increased likelihood of past experience with an unretrieved target. During retrieval failure, the increase in future-oriented FOK judgments with increasing cue familiarity was significantly less than the increase in past-oriented recognition judgments with increasing cue familiarity.     

Divided attention at encoding: Effect on feeling-of-knowing

This research investigated the effect of divided attention at encoding on feeling-of-knowing (FOK). Participants had to learn a 60 word-pair list under two experimental conditions, one with full attention (FA) and one with divided attention (DA). After that, they were administered episodic FOK tasks with a cued-recall phase, a FOK phase and a recognition phase. Our results showed that DA at encoding altered not only memory performance, but also FOK judgments and FOK accuracy. These findings throw some light on the central role of the quality of memory encoding to make accurate FOK judgments and provide new evidence supporting the relationship between memory and metamemory judgments.     

Contributions of metaknowledge to retrieval of natural categories in semantic memory

Retrieving the answer to a general knowledge question has been shown to involve two metacognitive processes--a feeling-of-knowing that initiates the search of long-term memory and a willingness to continue searching until an answer can be confidently stated. To extend this model, college students were asked to retrieve as many members of 2 natural categories as they could in 1 min. Examination of the points at which they switched categories revealed that they searched longer in categories of higher potency, and they switched earlier when the other category was of higher potency. They also searched the first category longer when they were allowed to switch only once during a trial rather than as often as they wished. It was concluded that feeling-of-knowing maintained search of a category and also contributed to the willingness to continue searching, and the constraint on switching impacted the willingness to continue.     

Feelings and Judgments of Knowing: Is There a Special Noetic State?

A. Koriat distinguishes between feeling-based and inferentially based feeling-of-knowing judgments. The former are attributable to partial information that is activated in implicit memory but not fully articulated. They are not, however, attributable to direct access to the target—an hypothesis that Koriat specifically repudiates. While there is considerable merit in the distinction that Koriat draws, and his emphasis on the possibility that people base at least some of their metacognitive judgments on implicit information seems well founded, it is argued that his rejection of the direct access view is premature. There may be a state—a true noetic state—in which people actually know the answer before they are able to express it. A case is made for further consideration of the scientific merits of the direct-access view of the noetic feelings people experience in imminent tip-of-the-tongue (TOT) states.     

The influence of near-threshold priming on metamemory and recall

A metamemory paradigm involving the use of near-threshold visual priming is developed in which a brief flash of a previously nonrecalled answer occurs, and then the person attempts to recall the answer and/or make feeling-of-knowing judgments. The major new finding is that the feeling of knowing did not detect perceptual input from a near-threshold prime that increased the recall of otherwise nonrecallable items. This finding has two important implications: (1) The feeling of knowing is not always more sensitive than recall as an indicant of information in memory (particularly, as an indicant of small amounts of information newly deposited into memory), and (2) 'monitored' information (that the feeling of knowing would be capable of detecting, as examined in previous research) can be combined with 'nonmonitored' information (that is newly deposited into memory and that the feeling of knowing does not detect) so as to produce the successful recall of an otherwise nonrecallable item.     

Do different metamemory judgments tap the same underlying aspects of memory?

We compared the predictions from several kinds of metamemory judgments (on the same set of items), both in terms of their predictive accuracy and in terms of the commonality of predictions. Undergraduates made judgments about the ease with which they could learn each item in a list (ease-of-learning judgments); then they learned every item, either to a minimal criterion of learning or with overlearning, and made judgments about how well they knew each item (judgments of knowing); finally, they returned 4 weeks later for a retention session and made feeling-of-knowing judgments on every time they could not recall, after which a recognition test assessed predictive accuracy. Ease-of-learning judgments had the least predictive accuracy. Surprisingly, however, the recognition of nonrecalled items was predicted equally well by judgments of knowing (made 4 weeks earlier) as by feeling-of-knowing judgments (made immediately prior to recognition). Moreover, those two kinds of judgments were only weakly correlated with each other, which implies that they do not tap memory in the same way.     

Memory and metamemory for semantic information in obsessive-compulsive disorder

Several studies have been conducted on OCD patients' memory and metamemory performance in episodic tasks. However, there is a clear lack of research addressing these issues for semantic memory (i.e., retrieval of information from long-term memory). Although findings regarding a memory deficit is somewhat equivocal, the empirical evidence clearly demonstrates that OCD patients with primarily checking compulsions show reduced confidence in their memory performance. The purpose of the present study was to investigate memory and metamemory performance of checkers in semantic memory domain. We compared checker OCD patients, non-checker OCD patients and normal controls on their ability to retrieve answers to general knowledge questions with a recall as well as a recognition test. We also investigated prospective (feeling-of-knowing (FOK)) and retrospective (confidence) metamemory judgments. Checker OCs were not poorer in retrieving semantic information from long-term memory. Neither were they less confident about their ability to remember currently unrecallable information in the future (FOK judgments) or about the accuracy of retrieved information (confidence judgments). Moreover, accuracy of metamemory judgments were comparable across groups. Overall, our results revealed that checker OCs do not show a memory or metamemory deficit when semantic memory was concerned, suggesting that any memory and metamemory deficit may be special to recently experienced materials.     

Measures of feeling-of-knowing accuracy: A new look at an old problem

Two ordinal measures of feeling-of-knowing performance appropriate for n × n data arrays are reviewed. Goodman and Kruskal's gamma provides a measure of association between recognition performance and feeling-of-knowing judgements. The Hamann coefficient provides a measure of agreement accuracy. The relative strengths and weaknesses of each measure are compared at length. A proof is provided, which reveals a lack of one-to-one relation between the two and suggests that they may be independent under most circumstances. It is concluded that both measures should be reported together as complementary indices as each captures a different facet of feeling-of-knowing performance. Alternative measures for gamma and the Hamann coefficient are considered and a number of recommendations are made for future research.     

Working memory load differentially affects tip-of-the-tongue states and feeling-of-knowing judgments

Tip-of-the-tongue states (TOTs) are judgments of the likelihood of imminent retrieval for items currently not recalled, whereas feeling-of-knowing judgments (FOKs) are predictions of successful recognition for items not recalled. The assumption has been that similar metacognitive processes dictate these similar judgments. In Experiment 1, TOTs and FOKs were compared for general information questions. Participants remembered four digits (working memory load) during target retrieval for half of the questions, and there was no memory load for the other questions. Working memory did not affect recall but decreased the number of TOTs and increased FOKs. In Experiment 2, participants maintained six digits during retrieval. TOTs decreased in the working memory condition, but FOKs remained constant. Experiment 3 replicated the results of Experiment 2 while asking for FOKs for recall. In each of the first three experiments, positive metacognitive judgments also affected working memory performance, supporting the idea that working memory and metamemory use similar monitoring processes. In Experiment 4, visual working memory did not affect TOTs or FOKs. The data support a view that TOTs and FOKs are separable metacognitive entities.