Demonstrations of a generation effect in context memory.

Generation often leads to increased memorability within a laboratory context (see, e.g., Slamecka & Graf, 1978). Of interest in the present study is whether the benefits of generation extend beyond item memory to context memory. To investigate this question, in three experiments, we asked subjects to remember in which of two contexts they had read or generated words. In Experiment 1, the contexts were two different rooms; in Experiment 2A, the contexts were two different computer screens; in Experiment 2B, the contexts were different perceptual characteristics of the to-be-remembered words. In all experiments, subjects were better at remembering the context of generated words than of read words.

Selecting one among many referents in spatial situation models.

Five experiments related anaphor resolution to a classic memory variable, namely, interference created by multiple uses of a given object-concept, and by spatial distance of the referent from the reader's focus of attention. Participants memorized a diagram of a building with rooms containing objects, and then read narratives describing characters' activities there. Reading was self-paced word by word. Accessibility was measured by readers' time to understand anaphoric sentences containing a definite noun phrase referring to an object in its room. Spatial distance between the object and the current focus of attention increased reading times for names of the object, the room, and sentence wrap-up. Multiple examples of a target-object increased its reading time only if they were scattered across different rooms. An associative model of memory retrieval during text comprehension was used to interpret the complex pattern of results.

Temporal and spatial distance in situation models.

In two experiments, we investigated how readers use information about temporal and spatial distance to focus attention on the more important parts of the situation model that they create during narrative comprehension. Effects of spatial distance were measured by testing the accessibility in memory of objects and rooms located at differing distances from the protagonist's current location. Before the test probe, an intervening episode was inserted in the narrative. Story time distance was manipulated by stating that the intervening episode lasted for either minutes or hours. Discourse time--that is, time spent reading from prime to test--was manipulated by describing the intervening episode either briefly or at length. Clear effects of story time distance and spatial distance on accessibility were found, whereas discourse time distance did not affect accessibility. The results are interpreted as supporting constructionist theories of text comprehension.

Cognitive impact of traumatic events.

The impact of traumatic experiences on cognitive processes, especially memory, is reviewed. The major psychological sequelae of trauma (reexperiencing, avoidance, hypervigilance) and posttraumatic stress disorder (PTSD) are noted and related to traditional views of fear conditioning. Evidence indicating enhanced memory for the gist of emotional events is reviewed as are psychological and neurophysiological mechanisms underlying this enhancement. This view is updated by introducing the distinction between explicit and implicit memory and its relevance to traumatic memory and PTSD. The central role of "the experiencing ego" in the storage and retrieval of episodic memories is postulated. This leads into discussion of dissociative experiences during traumas and the occasional amnesia for voluntary recall of the trauma accompanied by involuntary, uncontrollable flashbacks of it. The relationship of dissociative experiences to hypnotizability and to pathological reactions to traumas is discussed, although the interpretation of those correlations is questioned. The article concludes by noting that beyond conditioning of fear, traumas often violate and shake the victims' basic assumptions about the benevolence, justice, and meaningfulness of their physical and social worlds. Psychotherapy with trauma victims then needs to attend not only to extinguishing the victims' fear and feelings of extreme vulnerability, but also to rebuilding their basic beliefs about the relative benevolence of the world.

The metrics of spatial situation models.

The authors investigated the metrics of spatial distance represented in situation models of narratives. In 3 experiments, a spatial gradient of accessibility in situation models was observed: The accessibility of objects contained in the situation model decreased with increasing spatial distance between the object and the reader's focus of attention. The first 2 experiments demonstrated that this effect of spatial distance was purely categorical rather than Euclidean: Accessibility depended on the number of rooms located between the object and the focus of attention, not on the size of the rooms. Experiment 3 revealed, however, that participants were able to use information about Euclidean distance in a secondary task when necessary. The implications of these results for theories of narrative comprehension and hierarchical versus nonhierarchical theories of spatial memory are discussed.

Reactivating a reactivation theory of implicit memory.

Implicit and explicit memory tasks are interpreted within a traditional memory theory that distinguishes associations between different classes of memory units (sensory features, logogens, imagines, concepts, context tags). Associations from specific sensory features to logogens are strengthened by perceptual experiences, leading to specific perceptual priming. Associations among concepts are strengthened by use, leading to specific conceptual priming. Activating associations from concepts to logogens leads to semantic and associative priming. Item presentation also establishes a new association from it to a representation of the personal context, comprising an "episodic memory." Such contextual associations play a major role in explicit memory tasks such as recall or recognition. A critical assumption of the theory is that presentation of a given item strengthens its sensory and contextual associations independently; this permits the theory to explain various dissociations of implicit and explicit memory measures. Furthermore, by assuming that brain-injured patients with global amnesia have a selective deficit in establishing novel associations to the context, the theory can explain their deficits in explicit memory along side their intact implicit memory.

Does recoding interfering material improve recall?

In 4 experiments, the authors attempted to replicate an improvement in recall of target memories produced by a post-learning clue enabling participants to reorganize and segregate interfering material, as shown by G. H. Bower and T. Mann (1992). The 1st three experiments studied retroactive interference (RI) in free recall of an initial word list after participants were informed post-learning of a way to categorize a second, interfering list. In each case, the reorganizing clue failed to reduce RI. In the 4th experiment, interference during serial recall of an initial list of letters from a 2nd list was examined. Again, the reorganizing clue given after learning failed to reduce RI. Clearly, if the post-information effect is genuine, then better experimental arrangements will be required to demonstrate it more reliably.

A turning point in mathematical learning theory.

This target article by Estes (1950) sparked the mathematical learning theory movement, which took seriously the goal of predicting quantitative details of behavioral data from standard learning experiments. The central constructs of Estes's theory were stimulus variability, stimulus sampling, and stimulus-response association by contiguity, all cast within a framework enabling predictions of response probabilities and latencies. The math models enterprise flourished during the period 1950-1975 and provided successful quantitative accounts of data from Pavlovian and instrumental conditioning, probability learning, verbal learning, concept identification, and other standard learning paradigms. The techniques have been assimilated into the armamentarium of theoretical psychology. Stimulus sampling theory has faded away as it has been transformed into modern descendants such as connectionism and information-processing models of cognition.

Reducing retroactive interference: an interference analysis.

In 4 experiments on retroactive interference (RI), we varied paired-associate learning lists that produced either appreciable or negligible forgetting. When the category of the stimulus word predicted its response word category, and the response was relatively unique within its category, learning was extremely rapid, and negative transfer and RI were negligible. The more the competing primed items in the predicted response category, the slower the learning and the greater the RI. If cues and responses were unrelated, learning was very slow, and RI was appreciable. Thus, predictive relations that help stimuli retrieve unique responses greatly alter forgetting in RI paradigms.

Eliciting cryptomnesia: unconscious plagiarism in a puzzle task.

In three experiments we investigated cryptomnesia (unconscious plagiarism) and source memory using a word-search puzzle task. Subjects first alternated with a "computer partner" in locating words from 4 puzzles. They then attempted to recall their previously generated items as well as to locate additional new words. Substantially more plagiarism was committed in these tasks than was observed in a study by A. S. Brown and D. R. Murphy (1989), in which Ss generated category exemplars. Manipulations of retention interval (Experiment 1) and degree of encoding (Experiments 2a and 2b) reliably influenced plagiarism rates. Source confusions from a modified recognition memory task (Experiment 3) were used as the basis for a unitary relative strength model to explain both source and occurrence (item) forgetting.

Improving recall by recoding interfering material at the time of retrieval.

Our experiments demonstrate that interference of an interpolated list of items with recall of an original list can be substantially reduced by forming Ss just before testing how to reorganize and simplify the interpolated material. In Experiments 1 and 2, Ss better recalled an initial serial list of letters when informed at testing that an interpolated list spelled a certain phrase backward. Similarly, in Experiments 3 and 4, Ss better recalled an initial list of cities when told that the interpolated cities were also names of former U.S. presidents. Control experiments rule out several simple explanations. In contrast to an editing hypothesis, the postorganizing clue helped recall even when problems of list differentiation were minimized. Current memory models appear unable to explain this benefit of a postlearning clue that enables Ss to segregate the interpolated material from the to-be-remembered material.

Congruency effects in part-list cuing inhibition.

In demonstrations of part-list cuing inhibition, subjects who are shown a subset of studied list words recall fewer noncue words than subjects not shown such part-list cues. We propose that part-list inhibition is governed in part by an incongruency principle: Inhibition occurs to the extent that part-list cues induce a retrieval framework different from that used to encode list items. In Experiment 1, word lists were studied followed by a test of free recall either without cues, or with cue words serially organized to be either congruent or incongruent with the order of studied items. In Experiments 2-4, cues consisted of every second study item in the original presentation order (congruent ones) or reordered to form famous names or familiar idioms that had been hidden in the study list (incongruent cues). More part-list inhibition was observed with incongruent cues than congruent cues in all 4 experiments.

Praise or blame? Affective influences on attributions for achievement.

Three experiments showed that mood influences achievement attributions and that cognitive processes underlie these effects. In Experiment 1, happy Ss made more internal and stable attributions for success than failure in typical 'life dilemmas'. In Experiment 2, attributions for real-life exam performance were more internal and stable in a happy than in a sad mood. Dysphoric moods resulted in self-critical rather than self-enhancing attributions, contrary to motivational theories, but consistent with cognitive models and the clinical literature on depression. In Experiment 3 this pattern was repeated with direct self vs. other comparisons, and for self-efficacy judgements. The results are interpreted as supporting cognitive rather than motivational theories of attribution biases. The implications of the results for clinical research, and contemporary affect-cognition theories are considered.

Mental models in narrative comprehension.

Readers of stories construct mental models of the situation and characters described. They infer causal connections relating characters' actions to their goals. They also focus attention on characters' movements, thereby activating nearby parts of the mental model. This activation is revealed in readers' faster answering of questions about such parts, with less facilitation the greater their distance from the focus. Recently visited as well as imagined locations are also activated for several seconds. These patterns of temporary activation facilitate comprehension.

From conditioning to category learning: an adaptive network model.

We used adaptive network theory to extend the Rescorla-Wagner (1972) least mean squares (LMS) model of associative learning to phenomena of human learning and judgment. In three experiments subjects learned to categorize hypothetical patients with particular symptom patterns as having certain diseases. When one disease is far more likely than another, the model predicts that subjects will substantially overestimate the diagnosticity of the more valid symptom for the rare disease. The results of Experiments 1 and 2 provide clear support for this prediction in contradistinction to predictions from probability matching, exemplar retrieval, or simple prototype learning models. Experiment 3 contrasted the adaptive network model with one predicting pattern-probability matching when patients always had four symptoms (chosen from four opponent pairs) rather than the presence or absence of each of four symptoms, as in Experiment 1. The results again support the Rescorla-Wagner LMS learning rule as embedded within an adaptive network model.

Mood effects on person-perception judgments.

How does mood affect the way we learn about, judge, and remember characteristics of other people? This study looked at the effects of mood on impression formation and person memory. Realistic person descriptions containing positive and negative details were presented to subjects experiencing a manipulated happy or sad mood. Next, impression-formation judgments were obtained, and subjects' recall and recognition of details of the characters were assessed. Results showed that subjects spent longer learning about mood-consistent details but were faster in making mood-consistent judgments. Overall, happy subjects formed more favorable impressions and made more positive judgments than did sad subjects. Both cued recall and recognition memory were superior for mood-consistent characteristics. Positive mood had a more pronounced effect on judgments and memory than did negative mood. These findings are discussed in terms of recent theories of mood effects on cognition, and the likely implications of the results for everyday person-perception judgments are considered.

Learning and memory for personality prototypes.

Although personality traits are commonly assumed to be represented in memory as schemata, little research has addressed whether such schemata can be learned from observation. Subjects in three studies classified 60 person instances into group members and nonmembers as defined by the instances' match to a complex personality prototype. To simulate learning of fuzzy categories, each person instance provided conflicting cues to group membership. Learning for instances' group membership was excellent across studies. In Study 1, frequency of cues indicating group membership was greatly overestimated among nongroup instances. In Study 2, schema-consistent memory bias was revealed for person instances. In Study 3, schemata of consistently positive (or negative) traits were learned faster than arbitrary schemata. The findings implicated frequency sensitivity of memory (Estes, 1986), and a model of probabilistic cued-memory retrieval was developed to account for the effects. The findings were then discussed in relation to everyday cognitive performance.

Priming effects and recognition memory in young and elderly adults.

The present study explores the effects of age on the priming of alternate homophone spellings and recognition memory. Sixteen young and sixteen elderly adults were given a general information test, a spelling test, and a test of recognition memory. By embedding the less frequently spelled member of different homophone units (e.g., write vs. right) in the general information questions, certain of the homophones were primed during this task. The effect of this priming was assessed through the subjects' choice of spelling for these words on the spelling test. Recognition memory was assessed by asking subjects to indicate which words from a longer list were presented during the spelling test. As found in prior research priming effects were observed in younger subjects; however, no significant priming effects occurred in the older age group. On the recognition test, homophones were more often correctly recognized than nonhomophones, and priming affected the scores of the young negatively, but had no effects, positive or negative, on the elderly. These results suggest possible differences in the underlying bases of memory loss in aged adults and amnesics.