Working-memory capacity, proactive interference, and divided attention: Limits on long-term memory retrieval.

Two experiments examined how individual differences in working-memory capacity (WM) relate to proactive interference (PI) susceptibility. We tested high and low WM-span participants in a PI-buildup task under single-task or dual-task (load) conditions. In Experiment 1, a finger-tapping task was imposed during encoding and retrieval of each list; in Experiment 2, tapping was required during encoding or retrieval. In both experiments, low spans showed greater PI than did high spans under no load, but groups showed equivalent PI under divided attention. Load increased PI only for high spans, suggesting they use attention at encoding and retrieval to combat PI. In Experiment 2, only low spans showed a dual-task cost on List 1 memory, before PI built up. Results indicate a role for attentional processing, perhaps inhibitory in nature, at encoding and retrieval, and are discussed with respect to theories of WM and prefrontal cortex function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Causal inferences in reading: From immediate activation to long-term memory.

Three different tasks were used to investigate the time course of drawing causal inferences. Participants read passages that contained a causal coherence break that could be resolved by reactivating a concept presented earlier in the passage. In Experiment 1, participants named a probe word that represented the earlier mentioned cause more quickly after encountering the causal coherence break, suggesting that the causal concept had quickly been reactivated. In Experiment 2, participants were slow to read a sentence after the causal coherence break that contradicted the intended inference indicating that the inference had been encoded and retained in working memory. In Experiment 3, the results of a recall task indicated that the causal link was also included in the long-term memory representation of the text. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Human hippocampal activation in the delayed matching-and nonmatching-to-sample memory tasks: An event-related functional MRI approach.

The delayed matching-to-sample (DMS) and delayed nonmatching-to-sample (DNMS) memory tasks are standard tools used to probe visual recognition memory in human and nonhuman primates. Previous research indicates that structures within the medial temporal lobe, including the hippocampus, make up a crucial memory circuit for successful performance on these tasks. In the present investigation, event-related functional magnetic resonance imaging was used to examine activation in the hippocampus proper during these memory tasks relative to a perceptuomotor task involving the same stimuli. The results indicate that both memory tasks elicited greater activation in the right hippocampus during the encoding phase. These findings are consistent with the work from human patients and animal studies, indicating hippocampal involvement in the DMS and DNMS tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Autobiographical memory specificity and affect regulation: An experimental approach.

This study investigated J. M. G. Williams's (1996) affect-regulation hypothesis that level of specificity of autobiographical memory (AM) is used to minimize negative affect. It was found that a negative event leads to more reports of subjective stress in high- as compared with low-specific participants. Also, afterward, high-specific participants rated their unprompted memories for the event as more unpleasant. The results indicate that, relative to high specificity, being less specific in the retrieval of AMs is associated with less affective impact of a negative event. Results are discussed within the affect-regulation model. It is suggested that future research take a more functional perspective on AM specificity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Resolving the relationships between placebos, misattribution, and insomnia: An individual-differences perspective.

Hypothesized that insomniacs who are more attentive to internal bodily processes would be more apt to yield a reverse placebo effect (i.e., go to sleep faster when given an "arousal" placebo and vice versa), whereas those attentive to external stimuli would be more likely to be directly influenced by the suggested effects of the placebo. 30 insomniac college students completed trait measures of private body consciousness, private self-consciousness, and self-esteem. Ss were given placebos to take before bedtime and were told that the capsules had arousing or relaxing side effects. As predicted, Ss with high private body consciousness exhibited a stronger reverse placebo effect than did Ss low on this dimension. Subsequent analyses revealed that this effect was entirely attributable to the low- rather than to the high-self-esteem Ss. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pigeon visual memory capacity.

Four experiments examined visual memory capacity in 13 White Carneaux pigeons. In Exp I, Ss learned to discriminate between 80 pairs of random shapes. Memory for 40 of those pairs was only slightly poorer following 490 days without exposure. In Exp II, 80 pairs of photographic slides were learned; 629 days without exposure did not significantly disrupt memory. In Exp III, 160 pairs of slides were learned; 731 days without exposure did not significantly disrupt memory. In the final experiment, Ss learned to respond appropriately to 40 pairs of slides in the normal orientation and to respond in the opposite way when the slides were left–right reversed. After an interval of 751 days, there was a transient disruption in discrimination. These experiments demonstrate that pigeons have a heretofore unsuspected capacity with regard to both breadth and stability of memory for abstract stimuli and pictures. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning from instructional text: Test of an individual-differences model.

An individual-differences model of learning from instructional text was tested on 211 Air Force recruits. The results strongly supported the model, with a high level of fit for a structural equation modeling analysis using LISREL 8 (K. J?reskog & D. S?rbom, 1993). According to the model, learning from text is determined by making connections among ideas, including ideas from the text and from prior knowledge. Making the connections depends in part on 4 variables that differ among individuals: metacognition, specifically the ability to sense that one's mental representation is not coherent and consequently needs extra connections; inference-making ability, which spreads activation among the elements within working memory, which provides the arena in which the connections are made; and domain knowledge, which provides prior knowledge elements for use by the inference-making process to make connections. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The long-term mechanically ventilated patient. An outcomes management approach

We have studied whether there is natural genetic variation for mutation frequencies, and whether any such variation is environment-related. Mutation frequencies differed significantly between wild strains of the fungus Sordaria fimicola isolated from a harsher or a milder microscale environment in "Evolution Canyon," Israel. Strains from the harsher, drier, south-facing slope had higher frequencies of new spontaneous mutations and of accumulated mutations than strains from the milder, lusher, north-facing slope. Collective total mutation frequencies over many loci for ascospore pigmentation were 2.3, 3.5 and 4.4% for three strains from the south-facing slope, and 0.9, 1.1, 1.2, 1.3 and 1.3% for five strains from the north-facing slope. Some of this between-slope difference was inherited through two generations of selfing, with average spontaneous mutation frequencies of 1.9% for south-facing slope strains and 0.8% for north-facing slope strains. The remainder was caused by different frequencies of mutations arising in the original environments. There was also significant heritable genetic variation in mutation frequencies within slopes. Similar between-slope differences were found for ascospore germination-resistance to acriflavine, with much higher frequencies in strains from the south-facing slope. Such inherited variation provides a basis for natural selection for optimum mutation rates in each environment.     

Simple and complex word spans as measures of working memory capacity.

Five experiments investigated the effects of word length in simple word span tasks and complex operation and reading span tasks and the relationship between these tasks and reading comprehension. The 1st 2 experiments showed word length effects using both simple and complex memory span tasks and that both simple and complex span tasks correlated with reading comprehension. In the 3rd experiment, articulatory suppression did not eliminate word length effects. The final experiments showed that articulatory suppression eliminated the effect of word length when words were sampled with replacement from small fixed pools but not when sampled without replacement from a large pool. The word pool effects were not a result of concreteness of the words. It is concluded that the reading span does not measure a working memory specific to reading. Further, in immediate memory experiments, repeating words from trial to trial may lead to a more limited coding than is used with nonrepeated words. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

An individual-differences interpretation of the conflicting predictions generated by equity and expectancy theory.

The predictions and findings engendered by J. S. Adams's (1965) theory of equity are contrary to hypotheses deducible from expectancy theory for conditions of piece-rate overpayment. Suggested as the origin of the opposite predictions of equity theory and expectancy theory are the philosophical views of altruism and hedonism, respectively. In order to test the hypothesis that degree of moral development is a moderator of the equity phenomenon, 40 undergraduates were hired for a part-time job and assigned to simulated employment conditions. Support was obtained for anticipated differences in relationships such that increases in individual moral maturity were associated with conformity to equity theory's performance predictions for an overpayment condition (i.e., moral maturity was more inversely related to quantity of performance and most positively related to quality of performance in an overpayment condition relative to an equitable payment condition). Results support the hypothesis. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory capacity and aphasia.

The talk presents a capacity theory of syntactic comprehension disorders in aphasia. The work described was done in collaboration with Patricia Carpenter and Akira Miyake. The theory assumes that aphasic patients still possess the structural (syntactic) and procedural knowledge necessary to perform syntactic analysis, but that they suffer from reductions in working memory capacity for language. The theory explains how reductions in working memory capacity can lead to the pattern of comprehension breakdown observed in aphasic patients. According to a resource-reduction view of comprehension impairments in aphasia, patients are assumed to have intact structural and procedural knowledge to parse various sentences, but suffer from consequences of severely reduced working memory resources. Two types of experiments provide relevant supporting data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simulation of human long-term memory.

Reviews computer programs that simulate human long-term memory. A model of memory is described that may be constructed from the various programming efforts. Memory may be conceptualized as a large network with labeled links, where the nodes refer to ideas, and the links to the relations between those ideas. A model of this kind appears capable of giving meaningful answers to factual questions. The model may be so specified as to manifest spontaneous activity and local activity variations based upon excitation of associated contents; this explains context effects and other features. Retrieval, in the model, is effected by means of organized retrieval cues and complex information-retrieval strategies, which later permit the model to respond to cues differing from the original stimuli. (4 P. Ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Output interference in long-term memory.

Reports 2 experiments, with 70 and 140 undergraduates, concerning the role of output interference on the recall of organized material. Groups of Ss received blocked presentation of a 49-item list consisting of 7 items in each of 7 categories. At recall, the category name served as the retrieval cue. In Exp. I, a 20-sec recall interval was allowed for each category and 10 Ss were assigned to each group. In Exp. II, this interval was increased to 90 sec. and 20 Ss were assigned to each group. Results of both studies indicate that the number of words recalled from a category is dependent on the position of the category in the output sequence. In general, the earlier a category appears in the output sequence, the greater the number of words recalled from that category. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The contributions of primary and secondary memory to working memory capacity: An individual differences analysis of immediate free recall.

The present study tested the dual-component model of working memory capacity (WMC) by examining estimates of primary memory and secondary memory from an immediate free recall task. Participants completed multiple measures of WMC and general intellectual ability as well as multiple trials of an immediate free recall task. It was demonstrated that there are 2 sources of variance (primary memory and secondary memory) in immediate free recall and that, further, these 2 sources of variance accounted for independent variation in WMC. Together, these results are consistent with a dual-component model of WMC reflecting individual differences in maintenance in primary memory and in retrieval from secondary memory. Theoretical implications for working memory and dual-component models of free recall are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Putting time in perspective: A valid, reliable individual-differences metric.

Time perspective (TP), a fundamental dimension in the construction of psychological time, emerges from cognitive processes partitioning human experience into past, present, and future temporal frames. The authors' research program proposes that TP is a pervasive and powerful yet largely unrecognized influence on much human behavior. Although TP variations are learned and modified by a variety of personal, social, and institutional influences, TP also functions as an individual-differences variable. Reported is a new measure assessing personal variations in TP profiles and specific TP "biases." The 5 factors of the Zimbardo Time Perspective Inventory were established through exploratory and confirmatory factor analyses and demonstrate acceptable internal and test-retest reliability. Convergent, divergent, discriminant, and predictive validity are shown by correlational and experimental research supplemented by case studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Autobiographical memory as a reconstructive process: An extension of Ross's hypothesis.

Studied the implications of the model of M. Ross and M. Conway (1986) that autobiographical recall is a reconstructive process mediated by beliefs about the stability of the self and of the relevant database. At the beginning of the baseball season, 20 faculty and senior graduate students made predictions about the rank-order of finish for the teams in each Major League Division. They also provided self-ratings of baseball expertise. Six months later, the same Ss were unexpectedly asked to recall their predicted rankings. Ss who believed themselves to be stable experts produced recall protocols that were predicted by how the teams actually finished, consistent with Ross's hypothesis. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infants' long-term memory for stimulus color.

Two experiments examined the effects of a change in a reinforcing stimulus's color on memory for an operant response in 32 3- to 4-mo old infants. Ss were trained on 2 successive days to produce movement in an overhead mobile containing either all-blue or all-green objects. Subsequent exposure to a novel colored mobile produced a decrement in conditioned responding during cued-recall tests 1 but not 7 days following training. Data confirm that infants store information about a stimulus's color and indicate that this information is forgotten more rapidly than that representing other, more general features of the conditioning experience. Results also support the notion that the perception of stimulus color is a basic and early developing (perhaps innate) human characteristic and provide additional evidence of the importance of this variable for early memory. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task-set switching and long-term memory retrieval.

The authors tested the hypothesis of a close relationship between the intentional component of task-set switching ("advance reconfiguration;" R. D. Rogers & S. Monsell, 1995) and long-term memory (LTM) retrieval. Consistent with this hypothesis, switch costs are reported to be larger when the switched-to task involves high retrieval demands (i.e., retrieval of episodic information) than when it involves low retrieval demands (i.e., retrieval of semantic information). In contrast, switch costs were not affected by a primary-task difficulty manipulation unrelated to intentional retrieval demands (Experiment 2). Also, the retrieval-demand effect on switch costs was eliminated when time for advanced preparation or task cues explicitly specifying the task rules were provided (Experiment 3). Overall, results were consistent with the hypothesis that the intentional switch-cost component reflects the time demands of retrieving appropriate task rules from LTM. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit, long-term spatial contextual memory.

Learning and memory of novel spatial configurations aids behaviors such as visual search through an implicit process called contextual cuing (M. M. Chun & Y. Jiang, 1998). The present study provides rigorous tests of the implicit nature of contextual cuing. Experiment 1 used a recognition test that closely matched the learning task, confirming that memory traces of predictive spatial context were not accessible to conscious retrieval. Experiment 2 gave explicit instructions to encode visual context during learning, but learning was not improved and conscious memory remained undetectable. Experiment 3 illustrates that memory traces for spatial context may persist for at least 1 week, suggesting a long-term component of contextual cuing. These experiments indicate that the learning and memory of spatial context in the contextual cuing task are indeed implicit. The results have implications for understanding the neural substrate of spatial contextual learning, which may depend on an intact medial temporal lobe system that includes the hippocampus (M. M. Chun & E. A. Phelps, 1999). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention and retrieval from long-term memory.

Conducted 9 experiments with 152 female volunteers (mean age 44.4 yrs) to investigate the disrupting effect of a secondary task on retrieval from long-term memory. Exps I–V studied the influence of concurrent card sorting or digit span on free recall or paired-associate learning of word lists. Exp VI explored recall probability using a recognition paradigm in which accuracy and latency could be measured simultaneously. Exp VII explored the latency effect with a semantic memory paradigm, and Exp VIII required Ss to make semantic category judgments while retaining sequences of 6 digits. Exp IX examined the effect of concurrent digital load on the rate of generating items from semantic categories. Overall findings reveal that a demanding concurrent task did not reduce the probability of retrieving an item from semantic or episodic memory. However, concurrent load during learning substantially effected recall performance. A concurrent task during retrieval did not have a clear effect on latency. The contrast between the pattern shown by errors and by that shown by latencies suggests that attempts to estimate the attentional demands of any task should be interpreted with considerable caution when based on a single measure, such as performance errors, performance latency, or a response to a probe RT signal. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)