Emotional content enhances true but not false memory for categorized stimuli

Past research has shown that emotion enhances true memory, but that emotion can either increase or decrease false memory. Two theoretical possibilities—the distinctiveness of emotional stimuli and the conceptual relatedness of emotional content—have been implicated as being responsible for influencing both true and false memory for emotional content. In the present study, we sought to identify the mechanisms that underlie these mixed findings by equating the thematic relatedness of the study materials across each type of valence used (negative, positive, or neutral). In three experiments, categorically bound stimuli (e.g., funeral, pets, and office items) were used for this purpose. When the encoding task required the processing of thematic relatedness, a significant true-memory enhancement for emotional content emerged in recognition memory, but no emotional boost to false memory (Exp. 1). This pattern persisted for true memory with a longer retention interval between study and test (24 h), and false recognition was reduced for emotional items (Exp. 2). Finally, better recognition memory for emotional items once again emerged when the encoding task (arousal ratings) required the processing of the emotional aspect of the study items, with no emotional boost to false recognition (Exp. 3). Together, these findings suggest that when emotional and neutral stimuli are equivalently high in thematic relatedness, emotion continues to improve true memory, but it does not override other types of grouping to increase false memory.     

Problematic effects of aggregation in z ROC analysis and a hierarchical modeling solution

The confidence-rating recognition memory paradigm has been used extensively for testing theories of memory. Current methods for analyzing confidence-rating data require that data be aggregated over participants, items, or both. We show that this aggregation threatens claims of curvature in zROCs and distorts estimates of signal-distribution variance—the very findings that are used to make fine-grained distinctions between competing models. We develop a hierarchical signal detection model that accounts for variability from the sampling of participants and items in addition to variability from the underlying psychological processes. The model provides for accurate signal detection parameter estimates. With accurate estimates, the validity of benchmark findings in recognition memory may be assessed.     

Recognition hypermnesia: The growth of recognition memory (d') over time with repeated testing

This study sought to determine whether recognition hypermnesia (unforgetting) might be obtained over time with repeated testing of recognition memory. Four types of stimuli were investigated: pictures or words (captions) from configured (funny) or non-configured (non-funny) cartoons. Three recognition tests, each comprising the same stimulus and distractor items, were successively administered after the presentation of a large set of captioned cartoons. Silent think intervals of 5 min were interpolated between recognition tests. Recognition hypermnesia, measured by increasing d' estimates of accessible recognition memory, was obtained with the pictures from configured (funny) cartoons but not with any of the other groups.     

Decision processes in children's recognition memory

Kindergarteners and third graders were given a continuous recognition memory task involving two-digit numbers. In addition, a rating scale consisting of photographs of various facial expressions was used to obtain confidence judgments from the Ss. Conventional analyses as well as signal detection analyses of the data revealed the following results: (a) the overall performance of the third graders was superior to that of the kindergarteners; (b) memory strength decreased as the number of intervening items increased; (c) there was no difference in the forgetting rates of the two grade levels; (d) the third graders exhibited a more liberal response bias than the kindergarteners; (e) both the hit rate (probability of correctly labeling an old stimulus as old) and the false-alarm rate (probability of incorrectly labeling a new stimulus as old) increased across blocks of items; (f) the increases in the hit rate and the false-alarm rate over blocks were due to a change in criterion from a relatively conservative level to a more lenient one; (g) the lower the S's level of confidence in judging an item as old, the lower was the probability of that item actually being old; (h) the third graders were better than the kindergarteners at gauging the accuracy of their recognition responses. It was concluded that with respect to recognition memory, chidren as young as $\text{5}\text{1}\text{2}$ years old are capable, to some extent, of monitoring their own memory states.     

The detection model of recognition using know and remember judgments

The signal detection model forknow andremember recognition judgments was tested in two experiments. In Experiment 1, two predictions of the model were tested: (1) that measures of memory sensitivity,A′, are equivalent in value when based on either the recognition (know or remember) criterion or on the remember criterion; and (2) that there is a positive correlation between recognition bias and the proportion of know judgments that are hits, but no correlation between recognition bias and proportion of remember hits (Donaldson, 1996). Both predictions were supported by the data. In Experiment 2, the context of test items was manipulated to make it more or less similar to learning context. The detection model requires that memory sensitivity be the same for both recognition and remember judgments, regardless of test context. Alternatively, if remember judgments reflect only the retrieval of episodic information from memory, the two measures of memory sensitivity should become more disparate in value as learning and test context are made more similar. Memory sensitivity was generally the same in value for recognition and remember criteria but different across context conditions, thus supporting the detection model. The nature of the memory continuum used in detection theory is also discussed.     

The SIMCLAS Model: Simultaneous Analysis of Coupled Binary Data Matrices with Noise Heterogeneity Between and Within Data Blocks

In many research domains different pieces of information are collected regarding the same set of objects. Each piece of information constitutes a data block, and all these (coupled) blocks have the object mode in common. When analyzing such data, an important aim is to obtain an overall picture of the structure underlying the whole set of coupled data blocks. A further challenge consists of accounting for the differences in information value that exist between and within (i.e., between the objects of a single block) data blocks. To tackle these issues, analysis techniques may be useful in which all available pieces of information are integrated and in which at the same time noise heterogeneity is taken into account. For the case of binary coupled data, however, only methods exist that go for a simultaneous analysis of all data blocks but that do not account for noise heterogeneity. Therefore, in this paper, the SIMCLAS model, being a Hierarchical Classes model for the simultaneous analysis of coupled binary two-way matrices, is presented. In this model, noise heterogeneity between and within the data blocks is accounted for by downweighting entries from noisy blocks/objects within a block. In a simulation study it is shown that (1) the SIMCLAS technique recovers the underlying structure of coupled data to a very large extent, and (2) the SIMCLAS technique outperforms a Hierarchical Classes technique in which all entries contribute equally to the analysis (i.e., noise homogeneity within and between blocks). The latter is also demonstrated in an application of both techniques to empirical data on categorization of semantic concepts.     

Standing's power function in long-term memory

Summary Standing (1973) and Murray (1975) have both found that the number of items retrieved from long-term memory is a power function of the number of items presented. The present research reports three further experiments designed to validate this power function: the law was found to be upheld in paired associates recognition (for four levels of meaningfulness); for free recall (with or without retrieval cues at presentation and/or recall); and for incidental and intentional free recall and recognition. Some data of Roberts (1972) were also found to be fitted by a power function. The discussion deals with power functions as compared with linear functions and also with the relationships between slopes and intercepts of power functions.This research was supported by National Research Council of Canada Grant AO-126 to D.J. Murray. W.E. Hockley served as research assistant for Experiments 1 and 2; Experiment 3 was an Honours Thesis project carried out by Carol Pye.     

Caffeine cravings impair memory and metacognition

Cravings for food and other substances can impair cognition. We extended previous research by testing the effects of caffeine cravings on cued-recall and recognition memory tasks, and on the accuracy of judgements of learning (JOLs; predicted future recall) and feeling-of-knowing (FOK; predicted future recognition for items that cannot be recalled). Participants (N?=?55) studied word pairs (POND-BOOK) and completed a cued-recall test and a recognition test. Participants made JOLs prior to the cued-recall test and FOK judgements prior to the recognition test. Participants were randomly allocated to a craving or control condition; we manipulated caffeine cravings via a combination of abstinence, cue exposure, and imagery. Cravings impaired memory performance on the cued-recall and recognition tasks. Cravings also impaired resolution (the ability to distinguish items that would be remembered from those that would not) for FOK judgements but not JOLs, and reduced calibration (correspondence between predicted and actual accuracy) for JOLs but not FOK judgements. Additional analysis of the cued-recall data suggested that cravings also reduced participants’ ability to monitor the likely accuracy of answers during the cued-recall test. These findings add to prior research demonstrating that memory strength manipulations have systematically different effects on different types of metacognitive judgements.     

Tracking the emergence of memories: A category-learning paradigm to explore schema-driven recognition

Previous research has shown that prior knowledge structures or schemas affect recognition memory. However, since the acquisition of schemas occurs over prolonged periods of time, few paradigms allow the direct manipulation of schema acquisition to study their effect on memory performance. Recently, a number of parallelisms in recognition memory between studies involving schemas and studies involving category learning have been identified. The current paper capitalizes on these findings and offers a novel experimental paradigm that allows manipulation of category learning between individuals to study the effects of schema acquisition on recognition. First, participants learn to categorize computer-generated items whose category-inclusion criteria differ between participants. Next, participants study items that belong to either the learned category, the non-learned category, both, or neither. Finally, participants receive a recognition test that includes old and new items, either from the learned, the non-learned, or neither category. Using variations on this paradigm, four experiments were conducted. The results from the first three studies suggest that learning a category increases hit rates for old category-consistent items and false alarm rates for new category-consistent lures. Absent the category learning, no such effects are evident, even when participants are exposed to the same learning trials as those who learned the categories. The results from the fourth experiment suggest that, at least for false alarm rates, the effects of category learning are not solely attributable to frequency of occurrence of category-consistent items during learning. Implications for recognition memory as well as advantages of the proposed paradigm are discussed.     

Can a modified lineup procedure improve the usefulness of confidence?

In a face recognition, mini-lineup experiment we examined two aspects of the use of confidence about lineups. We modified the lineup procedure attempting to eliminate the difference in confidence–accuracy relationship between positive (old or identification) and negative (new or not present) decisions. In the modified procedure, participants: (1) selected the lineup member that best matched their memory of the target; (2) rated their confidence that the best match was indeed the target; and (3) indicated (yes/no) whether the best match was the target. Although the modified procedure produced higher accuracy than a standard simultaneous procedure, there was no evidence that it affected the confidence–accuracy relationship. Additionally, the modified procedure also allowed us to compare the extent to which confidence ratings versus binary recognition decisions better discriminated studied from unstudied faces. The results revealed a clear advantage for confidence, but indicated that binary responses were also a unique predictor.     

Recognition memory and intelligence

The assumption that individual differences in recognition memory are associated with individual differences in intelligence was explored by administering intelligence tests and tests of immediate visual recognition memory to a sample of 52 5-year-old children expected to vary widely from one another in intelligence. Each child was given the Peabody Picture Vocabulary Test (Form L) and two tests of immediate recognition memory: one test for 27 abstract patterns and one test for 27 unfamiliar cartoon faces. The mean PPVT-IQ for the sample was in the average range at 98.1. Interindividual variability in IQ proved to be high as reflected in the group SD of 22.6, with scores ranging from 40 to 136. The recognition tasks proved to be of moderate difficulty. Individual differences in memory for patterns were highly related to memory for faces (r = .76), indicating that the overall recognition test was reliable. The most important result of the present study was the strong association between recognition memory performance and PPVT-IQ of .70. The relation between recognition memory and IQ could not be accounted for by the inclusion of a few very low IQ children, since the association remained high at .61 when children with IQs below 75 were omitted from analysis. In short, the present results indicate that immediate recognition memory is highly associated with intelligence.     

A signal detection analysis of the recognition heuristic

The recognition heuristic uses a recognition decision to make an inference about an unknown variable in the world. Theories of recognition memory typically use a signal detection framework to predict this binary recognition decision. In this article, I integrate the recognition heuristic with signal detection theory to formally investigate how judges use their recognition memory to make inferences. The analysis reveals that false alarms and misses systematically influence the performance of the recognition heuristic. Furthermore, judges should adjust their recognition response criterion according to their experience with the environment to exploit the structure of information in it. Finally, the less-is-more effect is found to depend on the distribution of cue knowledge and judges’ sensitivity to the difference between experienced and novel items. Theoretical implications of this bridge between the recognition heuristic and models of recognition memory are discussed.     

Null category-length and target–lure relatedness effects in episodic recognition: A constraint on item-noise interference models

There are two main classes of model of interference effects in recognition memory: item-noise and context-noise. Item-noise models predict that a loss of memory discriminability will occur with an increase in the number of studied items from the same taxonomic category (category length, CL) and that forced-choice recognition performance will be higher when the target and lure are related rather than unrelated. Context-noise models, however, predict null effects for both of these manipulations. Although results from some recent experiments suggest that CL and target–lure relatedness have a trivial or no effect on memory discriminability when the related items from the same taxonomic category are “not back to back in the study list but are separated (spaced) by interleaving items from other semantic categories,” these experiments have methodological limitations that were eliminated in the present experiment in which exemplars representing category lengths of 2, 8, or 14 were presented spaced apart within the same study list. Recognition was tested using a yes/no recognition test or a two-alternative forced-choice recognition test in which the target and lure were either related or unrelated. In yes/no recognition, d′ decreased as CL increased, replicating prior research. However, when the slope of the z-ROC function is less than 1.0, as is typically so and was so in the present results, d′ differences can arise due to criterion shifts and are not necessarily due to memory discriminability differences. When the more appropriate measure of memory discriminability, d _a , was computed, CL had no effect in yes/no recognition, nor did it have an effect in forced-choice recognition, which also was not affected by target–lure relatedness. Thus, the present results are congruent with context-noise models and pose a challenge for item-noise models.     

Signal-detection analysis of recognition memory of obese subjects

Obese and normal-weight subjects were run on a series of recognition-memory tasks with low and high meaningful CVC trigrams. Subjects received feedback or no feedback regarding the appropriateness of their answers during testing for recognition memory. A signal-detection analysis was used to examine a relatively pure index of memory (d') as compared to response-bias factors [Ln (beta)]. No significant main effect on memory of obese and control subjects was noted although a significant interaction indicated that obese subjects' memory increases over trials in a differential fashion from normal-weight individuals with poorer performance among the obese after 3 trials. Feedback facilitated memory for both groups. Analysis of response criteria [Ln (beta)] showed no significant difference between groups. Highly meaningful trigrams had a significantly lower response criterion than low meaningful trigrams and there was a significant interaction of meaningfulness by trials. An interaction of feedback by meaningfulness was also present. Advantages of using a signal-detection analysis in memory studies comparing obese and normal weight subjects are discussed. Ramifications of the present data for the internality/externality hypothesis of obesity are also discussed.     

The revelation effect for autobiographical memory: A mixture-model analysis

Participants provided information about their childhood by rating their confidence about whether they had experienced various events (e.g., “broke a window playing ball”). On some trials, participants unscrambled a key word from the event phrase (e.g., wdinwo—window) or an unrelated word (e.g., gnutge—nugget) before seeing the event and giving their confidence ratings. The act of unscrambling led participants to increase their confidence that the event occurred in their childhood, but only when the confidence rating immediately followed the act of unscrambling. This increase in confidence mirrors the “revelation effect” observed in word recognition experiments. In the present article, we analyzed our data using a new signal detection mixture distribution model that does not require the researcher to know the veracity of memory judgments a priori. Our analysis reveals that unscrambling a key word or an unrelated word affects response bias and discriminability in autobiographical memory tests in ways that are very similar to those that have been previously found for word recognition tasks.     

No Benefit of Eye-Closure Rehearsal in a Unimodal Recognition Memory Test for Word Items

Recent studies have suggested that closing the eyes helps memory retrieval in recall tests for audiovisual clips that contain multimodal information. In two experiments, we examined whether eye-closure improves recognition memory performance for word lists presented unimodally (i.e., visually or aurally). In the encoding phase, participants saw or heard a list of unrelated, meaningful word items. After a fixed retention interval of 1 week (Experiment 1, n = 110) and 5 min (Experiment 2, n = 44), the participants were asked to mentally rehearse the items with their eyes open or closed, and then they performed a recognition test. The results revealed no effect of eye-closure rehearsal on recognition performance. We discuss the possible reasons why no eye-closure benefit was found in recognition memory tests for unrelated word items.     

On the contribution of perceptual fluency and priming to recognition memory

Repetition priming has been shown to be independent of recognition memory. Thus, the severely amnesic patient E.P. has demonstrated intact stem completion priming and perceptual identification priming, despite at-chance performance on recognition memory tasks. It has also been shown that perceptual fluency can influence feelings of familiarity, in the sense that items perceived more quickly tend to be identified as familiar. If studied items are identified more fluently, due to perceptual priming, and fluency leads to familiarity, why do severely amnesic patients perform no better than chance on recognition memory tasks? One possibility is that severely amnesic patients do not exhibit normal fluency. Another possibility is that fluency is not a sufficiently strong cue for familiarity. In two experiments, 2 severely amnesic patients, 3 moderately amnesic patients, and 8 controls saw words slowly clearing from a mask. The participants identified each word as quickly as possible and then made a recognition (old/new) judgment. All the participants exhibited fluency, in that old responses were associated with shorter identification times than new responses were. In addition, for the severely amnesic patients, priming was intact, and recognition memory performance was at chance. We next calculated how much priming and fluency should elevate the probability of accurate recognition. The tendency to identify studied words rapidly (.6) and the tendency to label these rapidly identified words old (.6) would result in 36% of the studied words being labeled old. Other studied words were identified slowly (.4) but were still labeled old (.4), resulting in an additional 16% of studied words labeled old. Thus, the presence of fluency increases the probability of accurate recognition judgments to only 52% (chance = 50%). This finding explains why amnesic patients can exhibit both priming and fluency yet still perform at chance on recognition tests.     

Electrophysiological correlates of encoding processes in a full-report visual working memory paradigm

Why are some visual stimuli remembered, whereas others are forgotten? A limitation of recognition paradigms is that they measure aggregate behavioral performance and/or neural responses to all stimuli presented in a visual working memory (VWM) array. To address this limitation, we paired an electroencephalography (EEG) frequency-tagging technique with two full-report VWM paradigms. This permitted the tracking of individual stimuli as well as the aggregate response. We recorded high-density EEG (256 channel) while participants viewed four shape stimuli, each flickering at a different frequency. At retrieval, participants either recalled the location of all stimuli in any order (simultaneous full report) or were cued to report the item in a particular location over multiple screen displays (sequential full report). The individual frequency tag amplitudes evoked for correctly recalled items were significantly larger than the amplitudes of subsequently forgotten stimuli, regardless of retrieval task. An induced-power analysis examined the aggregate neural correlates of VWM encoding as a function of items correctly recalled. We found increased induced power across a large number of electrodes in the theta, alpha, and beta frequency bands when more items were successfully recalled. This effect was more robust for sequential full report, suggesting that retrieval demands can influence encoding processes. These data are consistent with a model in which encoding-related resources are directed to a subset of items, rather than a model in which resources are allocated evenly across the array. These data extend previous work using recognition paradigms and stress the importance of encoding in determining later VWM retrieval success.     

A within-subjects analysis of the relationship between memory span and processing rate in short-term memory

A within-subjects analysis of the relationship between memory span and processing rate for four stimulus classes in short-term memory indicated that while the two factors are correlated when averaged data is considered, as shown by Cavanagh (Psychological Review, 1972, 79, 525–530), the strength of the relationship for individual subjects varies from zero to unity. The intersubject correlations for each stimulus class were not consistent with the view that a unified model may be advanced to account for performance in recall and recognition tasks in shortterm memory.