Subjective memorability and the mirror effect.

The mirror effect refers to the common finding that hit and false alarm rates on a recognition test are inversely related. The present research investigated the generality of the mirror effect (to rare words) and tested whether the effect might be grounded in accurate estimates of word memorability. The first 2 experiments showed that although high- and low-frequency words exhibit a mirror effect, rare words do not. Furthermore, contrary to expectations, Ss consistently (and mistakenly) predicted that memorability was directly correlated with frequency of usage. These findings weight against the idea that the mirror effect arises because of a S's ability to reject low-frequency lures on the grounds that such words would have been remembered had they appeared previously. Instead, the rejection of lures from different frequency categories may be determined by their semantic or phonemic overlap with list targets, and an analysis along these lines may help to explain why rare words constitute an exception to the otherwise ubiquitous mirror effect.     

The effect of category focus at encoding on category frequency estimation strategies

We investigated whether category focus at encoding affects how people estimate category frequencies. Participants in three experiments viewed items of various categories. They estimated category frequencies after categorizing them into relevant versus irrelevant categories (Experiments 1-2) or after categorizing versus memorizing them (Experiment 3). Verbal protocols (Experiments 2A and 2B), response latencies (Experiments 2A and 2B), frequency estimate changes (Experiment 2B), and the relationships between objective and estimated category frequencies and instance recall (Experiments 1-3) showed that the participants mainly used availability to estimate category frequencies after memorizing instances (Experiment 3) or after categorizing them into irrelevant categories (Experiments 1-2). After categorizing items into relevant categories, the participants relied more often on stored category frequency information (Experiments 1-3).     

The modulating influence of category size on the classification of exception patterns

Generalization gradients to exception patterns and the category prototype were investigated in two experiments. In Experiment 1, participants first learned categories of large size that contained a single exception pattern, followed by a transfer test containing new instances that had a manipulated similarity relationship to the exception or a nonexception training pattern as well as distortions of the prototype. The results demonstrated transfer gradients tracked the prototype category rather than the feedback category of the exception category. In Experiment 2, transfer performance was investigated for categories varying in size (5, 10, 20), partially crossed with the number of exception patterns (1, 2, 4). Here, the generalization gradients tracked the feedback category of the training instance when category size was small but tracked the prototype category when category size was large. The benefits of increased category size still emerged, even with proportionality of exception patterns held constant. These, and other outcomes, were consistent with a mixed model of classification, in which exemplar influences were dominant with small-sized categories and/or high error rates, and prototype influences were dominant with larger sized categories.     

The movement-induced self-reference effect: enhancing memorability through movement toward the self

Much evidence suggests that bodily actions affect cognitive states. In particular, pulling owned objects toward the self improves memory for those objects compared to memory for objects pushed away from the self. Experiments 1 and 2 examined the effect of incidental joystick movement on static stimuli, hypothesizing that using the physical self (rather than a computer monitor) as a reference point would enhance memory for items categorized via a toward-the-self action but not toward-the-computer-monitor action. Experiment 3 examined whether movement toward an external representation of self, one’s cellular phone, would enhance memory compared to the same movement toward an unfamiliar phone. Recognition memory was enhanced for both words and pictures evaluated during movements toward a representation of the self, regardless of whether the representation was a physical self or a disembodied self. Furthermore, movement toward the self enhanced memory, rather than movement away from the self depressing memory. These results suggest that self-referential processing can be induced by an approach motor action and impact episodic memory regardless of intention to learn, stimulus type, or motion of the stimuli. They also suggest that self-referential memory advantage can be disembodied.     

Multiple trials may yield exaggerated effect size estimates

Published psychological research attempting to support the existence of small and medium effect sizes may not have enough participants to do so accurately, and thus, repeated trials or the use of multiple items may be used in an attempt to obtain significance. Through a series of Monte-Carlo simulations, this article describes the results of multiple trials or items on effect size estimates when the averages and aggregates of a dependent measure are analyzed. The simulations revealed a large increase in observed effect size estimates when the numbers of trials or items in an experiment were increased. Overestimation effects are mitigated by correlations between trials or items, but remain substantial in some cases. Some concepts, such as a P300 wave or a test score, are best defined as a composite of measures. Troubles may arise in more exploratory research where the interrelations among trials or items may not be well described.     

The modulating influence of category size on the classification of exception patterns

Generalization gradients to exception patterns and the category prototype were investigated in two experiments. In Experiment 1, participants first learned categories of large size that contained a single exception pattern, followed by a transfer test containing new instances that had a manipulated similarity relationship to the exception or a nonexception training pattern as well as distortions of the prototype. The results demonstrated transfer gradients tracked the prototype category rather than the feedback category of the exception category. In Experiment 2, transfer performance was investigated for categories varying in size (5, 10, 20), partially crossed with the number of exception patterns (1, 2, 4). Here, the generalization gradients tracked the feedback category of the training instance when category size was small but tracked the prototype category when category size was large. The benefits of increased category size still emerged, even with proportionality of exception patterns held constant. These, and other outcomes, were consistent with a mixed model of classification, in which exemplar influences were dominant with small-sized categories and/or high error rates, and prototype influences were dominant with larger sized categories.     

The relation between category and magnitude estimates of tactile intensity

The effect of various types (sandpaper, spoke, spiral, and white) and speeds (0, 1/2, 3, 6, 12, and 30 rpm) of rotating disk backgrounds upon 276 Ss’ estimates of the apparent verticality of a line moved toward physical verticality in either a clockwise or counterclockwise direction was investigated. The general finding was that the estimate of verticality was displaced away from pretest judgments in the direction of the disk rotation. The speed of rotation was significant with maximal vertical displacement at 6 rpm. The direction of line movement was significant with the result that maximal vertical displacement occurred when the line was moved in opposition to the direction of disk rotation. The type of disk employed made a significant difference in the estimates only when the line movement was opposite from the direction of disk rotation. Disks with inadequate stimulus contours (white) produced no significant effect. Results are discussed in terms of stimulus contour and ocular torsion.     

Accuracy of effect size estimates from published psychological research

A Monte-Carlo simulation was used to model the biasing of effect sizes in published studies. The findings from the simulation indicate that, when a predominant bias to publish studies with statistically significant results is coupled with inadequate statistical power, there will be an overestimation of effect sizes. The consequences such an effect size overestimation will then have on meta-analyses and power analyses are highlighted and discussed along with measures which can be taken to reduce the problem.     

The effect of age on rule-based category learning

An explicit, rule-based, category-learning task with abstract visual stimuli was administered to 50 healthy older adults and 48 younger adults. Accuracy and reaction time (RT) were examined for the effects of age, perceptual abilities, rule memory, rule complexity, stimulus novelty, and response competition. Older adults performed at equivalent levels to younger adults when applying a simple rule, but showed performance decrements when applying a more complex rule. The age effect interacted with both stimulus novelty and response competition, and was not eliminated after controlling for basic perceptual abilities and rule memory. The authors suggest that older adults show category learning deficits in conditions that require enhanced cognitive control. These results are discussed in reference to the growing body of literature regarding age-related change in executive abilities and frontal lobe function.     

The effects of natural category size on memory for episodic encodings

Previous findings indicate that natural category size affects cued recall but not recognition performance. Words that define or belong to larger categories are not as likely to be recalled in the presence of an extralist cue. However, category size has no effect on recognition in the presence of the target as the cue. Theoretically, this difference could be due to inherent differences between these tasks, to the use of different types of test cues, or to differences in the nature of the required responses (naming compared with “yes/no”decisions). Three experiments indicated that none of these factors is a sole determinant. Natural category size effects were found in cued-recall and recognition tasks, with extralist and target cues and regardless of the required response. The critical factor is whether the testing conditions require or encourage subjects to search the category defined by the cue. With the initiation of such a search, information represented in semantic memory is likely to influence memory for episodic information.     

Familiarity,memorability, and the effect of typicality on the recognition of faces

Typical faces are more poorly discriminated on tests of recognition than are atypical faces, an effect suggested to mediate similar findings for attractive or likable faces. We tested the hypothesis that the effect of typicality on recognition is a function of context-free familiarity and memorability, which function in opposition. Two orthogonal principal components were extracted from subjects' ratings of faces for typicality, familiarity, attractiveness, likability, and memorability--one consisting of the ratings of familiarity, attractiveness, and likability, and reflecting context-free familiarity, and the other consisting of the memorability rating. As expected, typicality loaded equally (r approximately .66), but with opposite sign, on both components. In subsequent experiments, both components were found to be significant and additive predictors of face recognition with no residual effect of typicality. General familiarity decreased discrimination, and the memorability component enhanced it, supporting the hypothesis. The results are discussed in terms of the mirror effect.     

Global subjective memorability and the strength-based mirror effect in recognition memory

Between-list manipulations of memory strength through repetition commonly generate a mirror effect, with more hits and fewer false alarms for strengthened items. However, this pattern is rarely seen with within-list manipulations of strength. In three experiments, we investigated the conditions under which a within-list mirror effect of strength (items presented once or thrice) is observed. In Experiments 1 and 2, we indirectly manipulated the overall subjective memorability of the studied lists by varying the proportion of nonwords. A within-list mirror effect was observed only in Experiment 2, in which a higher proportion of nonwords was presented in the study list. In Experiment 3, the presentation duration for each item (0.5 vs. 3 sec) was manipulated between groups with the purpose of affecting subjective memorability. A within-list mirror effect was observed only for the short presentation durations. Thus, across three experiments, we found the within-list mirror effect only under conditions of poor overall subjective memorability. We propose that when the overall subjective memorability is low, people switch their response strategy on an item-by-item basis and that this generates the observed mirror effect.     

Recall-to-reject: The effect of category cues on false recognition

Four experiments examined the effect of category cueing on recall-to-reject, one of the central memory-editing mechanisms thought to prevent the occurrence of false memories. When category names were used as retrieval cues, the typically observed false recognition effect was eliminated for semantically associated distractors (Experiment 1a) and, moreover, a reduction in the absolute level of the false alarm rate was found for phonologically associated distractors (Experiment 2a). In addition to the old/new-recognition data, analyses using multinomial models support the interpretation that category cueing was successful in increasing the probability of recall-to-reject (Experiments 1b and 2b). The results are in line with dual-process theories of recognition memory and provide further evidence for recall-to-reject in single item recognition. They demonstrate its potential to reduce false recognition even when explicit instructions are not given. In addition, the results demonstrate that the paradigm can give rise to side effects that oppose recall-to-reject. A simultaneous familiarity increase can explain why many studies failed to find evidence for recall-to-reject in terms of false alarm rates.     

The effect of category learning on sensitivity to within-category correlations

A salient property of many categories is that they are not just sets of independent features but consist of clusters of correlated features. Although there is much evidence that people are sensitive to between-categories correlations, the evidence about within-category correlations is mixed. Two experiments tested whether the disparities might be due to different learning and test tasks. Subjects learned about categories either by classifying items or by inferring missing features of items. Their knowledge of the correlations was measured with classification, prediction, typicality, and production tests. The inference learners, but not the classification learners, showed sensitivity to the correlations, although different tests were differentially sensitive. These results reconcile some earlier disparities and provide a more complete understanding of people's sensitivities to within-category correlations.     

Typhoid Pollyanna: The effect of category valence on retrieval order of positive and negative category members

Previous research suggests that people process pleasant information more efficiently than unpleasant information. This phenomenon has been illustrated in a variety of contexts and paradigms, and is frequently referred to as the Pollyanna principle. One important aspect of the Pollyanna principle is that people tend to retrieve pleasant members of a category from semantic memory prior to unpleasant members of the same category. However, we propose that the retrieval advantage of favourably viewed category members holds only for positive categories and that prototypicality of category members might be a better predictor of ease of retrieval than favourability. These possibilities were tested in two studies. In Study 1, favourability effects on retrieval order were observed for positive categories but not for neutral or negative categories. In Study 2, prototypical category members were retrieved before less prototypical category members for both positive and negative categories. These results suggest that the Pollyanna principle might be the result of a confound between favourability and prototypicality for members of favourable categories.     

Influence of category size and target set size on unconscious priming by novel words

In support of their argument that unconscious priming by novel words is critically influenced by target set size, Kiesel, Kunde, Pohl, and Hoffman (2006) report priming from novel words when target sets were large but not when they were small. The present experiment examined the possibility that target set size interacts with category size. (In both experiments in Kiesel et al., category size was large.) In the present experiment, with a small target set, novel-word priming did occur when categories were small (farm animals, fruits) but not when categories were large (larger or smaller than a computer monitor). This finding suggests that, contrary to the position advanced by Kiesel et al., priming when target sets are small involves a mechanism other than preactivation of perceptual features belonging to the target set.     

The effect of category variability in perceptual categorization

Exemplar and distributional accounts of categorization make differing predictions for the classification of a critical exemplar precisely halfway between the nearest exemplars of 2 categories differing in variability. Under standard conditions of sequential presentation, the critical exemplar was classified into the most similar, least variable category, consistent with an exemplar account. However, if the difference in variability is made more salient, then the same exemplar is classified into the more variable, most likely category, consistent with a distributional account. This suggests that participants may be strategic in their use of either strategy. However, when the relative variability of 2 categories was manipulated, participants showed changes in the classification of intermediate exemplars that neither approach could account for.     

The influence of object familiarity on magnitude estimates of apparent size.

Three magnitude-estimation experiments were used to determine the exponents of the power function relating size judgments and physical size for two-dimensional familiar and unfamiliar stimuli. The exponent of the power function was used to index the effect of familiar size on perceived size under a variety of conditions, from full-cue to reduced-cue viewing conditions. Although the value of the exponents varied across the three experiments, within each experiment the exponent of the familiar stimulus was not significantly different from that of the unfamiliar stimulus, indicating that familiar size does not influence the rate of growth of perceived size. The results of a fourth experiment excluded a possible explanation of the findings of experiments 1-3 in terms of subjects responding to relative angular size as a consequence of the successive presentation of the different-sized representations of the familiar stimulus. Taken together, the present findings are consistent with the hypothesis that the influence of familiar size on estimates of size mainly reflects the intrusion of nonperceptual processes in spatial responses.     

The effect of midazolam on implicit and explicit memory in category exemplar production and category cued recall

Transfer‐appropriate processing theory (Roediger, Weldon, & Challis, 1989) proposes that dissociations between performance on explicit and implicit memory tests arise because these tests often rely on different types of information processing (e.g., perceptual processing vs conceptual processing). This perspective predicts that implicit and explicit memory tasks that rely primarily on conceptual processing should show comparable results, not dissociations. Numerous studies have demonstrated such similarities. It is, however, possible that these results arise from explicit memory contamination of performance on implicit memory tasks. To address this issue, an experiment was conducted in which participants were administered the sedative midazolam prior to study. Midazolam is known to create a temporary, but dense, period of anterograde amnesia. The effects of blocking stimulus materials by semantic category at study and generation at study were investigated on category exemplar production and category‐cued recall. The results of this study demonstrated a dissociation of the effects of midazolam on category exemplar production and category‐cued recall. Specifically, midazolam reduced the effect of blocking stimulus materials in category‐cued recall, but not in category exemplar production. The differential effect of midazolam on explicit and implicit memory is at odds with transfer‐appropriate processing theory and suggests that theories of memory must distinguish the roles of different types of conceptual processing on implicit and explicit memory tests.