Retrieval blocks in episodic and semantic memory.

A retrieval block (RB) refers to impaired accessibility in retrieving target information when semantically related information is presented or retrieved prior to target retrieval. A research review reveals that RBs occur in a variety of situations, including both episodic and semantic memory tasks. RBs have been most thoroughly studied in the part-list cuing paradigm in episodic recall, but similar principles seem to operate in other situations, including the A–B, A–D interference paradigm, episodic recognition, and the tip-of-the-tongue situation. Evidence for such RBs is problematic for theories postulating automatic spreading activation among associated nodes in memory. Difficulties with theories that account for such RBs are discussed. Further research on RBs may help illuminate similar phenomena, such as the effects of Einstellung in thinking and problem solving. (French abstract) (76 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrieval cues and short-term memory in capuchin monkeys.

Conducted 2 experiments, each with 3 adult female monkeys, dealing with the relationship between retrieval cues and delayed matching to sample (DMTS) performance. Exp I compared 2-choice and Yes-No DMTS to determine whether delayed matching performance was impeded by reducing the number of differential retrieval cues from 2 to 1. In Exp II, with 3 other Ss, all differential retrieval cues were eliminated by employing a delayed conditional matching task (DCM), which was compared to a corresponding 2-choice DMTS task. Exp I produced only a small, unreliable difference in favor of 2-choice DMTS, while in Exp II delayed matching behavior was equally effective with DCM and DMTS, provided that the conditional discriminations were well learned. Rather than attributing the retention evidenced in delayed matching tasks to underlying storage processes, it is suggested that the results may be an extension of discrimination behavior in which the major discriminative dimensions were temporal in nature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrieval from semantic memory and its implications for Alzheimer's disease.

In 3 experiments, participants generated category exemplars (e.g., kinds of fruits) while a voice key and computer recorded each response latency relative to the onset of responding. In Experiment 1, mean response latency was faster when participants generated exemplars from smaller categories, suggesting that smaller mental search sets result in faster mean latencies. In Experiment 2, a concurrent secondary task increased mean response latency, suggesting that slowed mental processing results in slower mean latencies. In Experiment 3, the mean response latency of Alzheimer's participants was faster than that of elderly controls, which is consistent with the idea that the semantic memory impairments of Alzheimer's disease patients stem primarily from a reduction in available items (as in Experiment 1) rather than retrieval slowing (as in Experiment 2). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of coding cues upon short-term memory of aged subjects.

Female elderly Ss with varying WAIS Digit Span abilities were compared on a short-term memory task taken with or without knowledge of appropriate codes. Results suggest that the interaction between ability and level of coding, and previous findings of age-related memory differences, may reflect real differences in ability to use organized materials rather than a deficit in knowing the appropriate code. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective short-term memory deficits arise from impaired domain-general semantic control mechanisms.

Semantic short-term memory (STM) patients have a reduced ability to retain semantic information over brief delays but perform well on other semantic tasks; this pattern suggests damage to a dedicated buffer for semantic information. Alternatively, these difficulties may arise from mild disruption to domain-general semantic processes that have their greatest impact on demanding STM tasks. In this study, mild semantic processing impairments were demonstrated in 2 semantic STM patients. They performed well on untimed semantic tasks but were deficient in accuracy and reaction times on speeded tasks. Demanding semantic production tasks were also affected. These patients were compared with a case series of individuals with semantic aphasia whose multimodal semantic difficulties stemmed from poor cognitive control. STM and semantic performance were more impaired in this group, but there were qualitative similarities to the semantic STM patients. The difference between the 2 patient types may be a matter of degree. In semantic aphasia, severe disruption to semantic control leads to global semantic impairments, whereas in semantic STM milder disruption might impact mainly on STM tests because of the high control demands of these tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Process complexity in semantic memory.

Are sentences verified by a lone computational mechanism, or does this mechanism race in parallel with a generally faster search of semantic memory? Rejecting either the single- or dual-process account would clarify whether semantic memory is structured or is a relatively unstructured (computational) system. This study examined verification reaction time (RT) distributions for a dissociation between fast and slow RTs due to the manipulation of semantic variables. A race between a search and a generally slower computational process should yield an RT distribution whose fastest RTs are usually determined by the search and whose slowest RTs are usually determined by computation. If a manipulation affects these 2 processes differently, the fast and slow RTs will be differentially affected. Results from 3 verification experiments support this view. Other results suggest even greater process complexity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in integrated semantic memory.

Used J. D. Bransford and J. J. Franks's (1971) paradigm of linguistic abstraction to examine age differences in the nature of stored semantic information. 20 young (mean age 18.7 yrs) and 18 old adults (mean age 67.3 yrs) served as Ss. Specifically, age differences on 2 dimensions of memory were examined: (a) integration of related content from separate sentences and (b) retention of precise semantic content. Young and old Ss were not found to differ in the precision of retained semantic information. Furthermore, while both age groups evidenced integration of information as indexed by a strong linear trend of recognition rate across sentence complexity, this trend did not interact with age, supporting the idea that both age groups showed comparable integration of linguistic information into holistic ideas. Implications for current conceptualizations of age differences in memory are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Slope analysis in short-term memory.

Presents procedures for transforming dichotomously scored data from short-term memory experiments into slope measures for evaluation by analysis of variance techniques. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Binomial variability in short-term memory.

Experiments in short-term memory usually collect binary data, e.g., an item is either correctly recalled or not. If the probability of recall is constant for Ss and/or items under a given condition, the proportion based on n observations can be transformed to angles by the arcsin transformation and will have variance 1/n. Violations of the assumptions are discussed and different strategies for pooling are assessed by conventional analysis of variance. Illustrative experiments with distractor and probe techniques, paired-associates and serial presentation, and single-trial free recall are briefly presented. The correspondence between observed and expected results seems good; apparently considerable latitude is possible in pooling Ss or items in data analyses of experiments in short-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Binding in short-term visual memory.

The integration of complex information in working memory, and its effect on capacity, shape the limits of conscious cognition. The literature conflicts on whether short-term visual memory represents information as integrated objects. A change-detection paradigm using objects defined by color with location or shape was used to investigate binding in short-term visual memory. Results showed that features from the same dimension compete for capacity, whereas features from different dimensions can be stored in parallel. Binding between these features can occur, but focused attention is required to create and maintain the binding over time, and this integrated format is vulnerable to interference. In the proposed model, working memory capacity is limited both by the independent capacity of simple feature stores and by demands on attention networks that integrate this distributed information into complex but unified thought objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Object orientation information in semantic and episodic memory.

Investigated the contributions of object orientation information in semantic and episodic memories to implicit and explicit memory test performance, in 3 experiments. 456 undergraduates were shown color photos of objects, and their memory was assessed either with an old/new recognition test or with a test that required Ss to identify slowly faded objects. The critical variables were the type of photo and the orientation at which the photos were displayed. Half of the targets were displayed in study condition and the rest in non-study condition (baseline). Results show that in Exp 1, baseline identification was slower for objects displayed upside down rather than upright. Baseline orientation-specific effects were much larger for cardinal than non-cardinal objects in Exps 2 and 3. The extent to which orientation is coded in the semantic and episodic memory representations of different kinds of objects is discussed. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamics of activation in semantic and episodic memory.

Two experiments with the adaptive priming procedure are reported to test discrete and continuous activation models for the structure of semantic and episodic memory. In Experiment 1, the prime and test stimuli were semantically associated words (e.g., bread–butter). In Experiment 2, episodic associations between the prime and test stimuli were established through paired associate learning. For both cases, the mixture prediction failed, and 2-state activation models were rejected. We conclude that models with only 2 discrete states of activation, that is, all-or-none models, do not accurately characterize the dynamics of activation in semantic and episodic memory. Higher order discrete or continuous models may better account for the results. Our findings are consistent with several current continuous models of spreading activation. They contrast, however, with those from previous work in which response-preparation processes appeared to proceed in a discrete, all-or-none fashion (Meyer, Yantis, Osman, & Smith, 1985). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age and rate of activation in semantic memory.

Two word-primed picture-naming experiments were carried out to test the hypothesis that rate of activation in semantic memory is slower for older adults than for young adults. The presence of priming effects, both positive and negative, was taken as evidence of activation. In Exp 1 there was no age difference in the time of onset of either facilitation or inhibition by primes. A computer simulation, based on a simple connectionist model, showed that slower processing would have only a minimal effect on the time of onset of priming effects under the assumptions of the model; however, offset of inhibition by primes would be delayed if processing rate were reduced. In Exp 2 older adults showed inhibition by primes over a longer interval than did young adults, which was taken as evidence that the general slowing associated with aging extends to the transmission of activation at the earliest levels of cognitive processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exploring developmental differences in visual short-term memory and working memory.

Although visuospatial short-term memory tasks have been found to engage more executive resources than do their phonological counterparts, it remains unclear whether this is due to intrinsic differences between the tasks or differences in participants’ experience with them. The authors found 11-year-olds’ performances on both visual short-term and working memory tasks to be more greatly impaired by an executive suppression task (random number generation) than were those of 8-year-olds. Similar findings with adults (e.g., Kane & Engle, 2000) suggest that the imposition of a suppression task may have overloaded the older children’s executive resources, which would otherwise be used for deploying strategies for performing the primary tasks. Conversely, the younger children, who probably never had the capacity or know-how to engage these facilitative strategies in the first place, performed more poorly in the single task condition but were less affected in the dual task condition. These findings suggest that differences in the children’s ability to deploy task-relevant strategy are likely to account for at least part of the executive resource requirements of visual memory tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Long-term semantic memory versus contextual memory in unconscious number processing.

Subjects classified visible 2-digit numbers as larger or smaller than 55. Target numbers were preceded by masked 2-digit primes that were either congruent (same relation to 55) or incongruent. Experiments 1 and 2 showed prime congruency effects for stimuli never included in the set of classified visible targets, indicating subliminal priming based on long-term semantic memory. Experiments 2 and 3 went further to demonstrate paradoxical unconscious priming effects resulting from task context. For example, after repeated practice classifying 73 as larger than 55, the novel masked prime 37 paradoxically facilitated the "larger" response. In these experiments task context could induce subjects to unconsciously process only the leftmost masked prime digit, only the rightmost digit, or both independently. Across 3 experiments, subliminal priming was governed by both task context and long-term semantic memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrieval processes in transactive memory systems.

Two experiments examined retrieval processes in transactive memory systems (D. M. Wegner, 1987). In Experiment 1, intimate couples who worked face to face performed better on a knowledge-pooling task than strangers who worked face to face and better than intimate couples who worked via a computer conferencing system. Additional analyses indicated that intimate couples when interacting face to face were better able to determine which partner was correct on questions that only 1 member knew the answer to prior to discussion. In Experiment 2, intimate couples scored significantly better on the knowledge task when they had access to either nonverbal or paralinguistic communication cues than when they had access to neither. Taken together, the results indicate that both nonverbal and paralinguistic communication play an important role in the retrieval of knowledge in transactive memory systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Imagery and interference in sequential short-term memory.

Conducted an experiment with 132 college students to compare the disruptive effects of irrelevant information (names of colors) superimposed on relevant information (bands of colors) with the effects of irrelevant information occupying the interval between stimuli. Irrelevant information disrupted performance only when it occupied the interval between stimuli, suggesting that interference was primarily with the rehearsal process and not with the perceptual process. It made no difference whether the names of colors were the same as or different from the bands of colors. Analysis of control conditions suggests that Ss can better "keep track" of colors than color names. Results are discussed in terms of visual imagery and the spatial window model of "keeping-track" performance. (French summary) (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Searching memory for physical and semantic information.

Three experiments, each with 12 paid undergraduates, determined whether scanning active memory for 2 types of information in parallel depends on the existence of different memory codes. Ss searched short lists of items for 2 types of semantic information, 2 types of physical information, or information of both types. It was found that both searches were conducted in parallel no matter what the nature of the information retrieved. Such parallel processing constitutes one strategy for improving the efficiency of searching active memory. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sparing of semantic memory in Alzheimer's disease.

A number of investigators have suggested that unlike the normal elderly population, patients with Alzheimer's disease have a severe semantic-memory deficit. However, the semantic-memory tasks used in previous studies have been confounded by the heavy demands they placed on effortful processing. In the present study, 20 demented (mean age 71 yrs) and 20 normal (mean age 69.8 yrs) elderly Ss were given a battery of episodic-memory tasks and 3 tasks that examined how intact and accessible their semantic memory was under conditions that did not require effortful processing. Although the demented Ss were greatly inferior to the normal Ss on the episodic-memory tests, they performed equally well on the semantic-memory test: The naming latency of both groups was equally facilitated by a semantic prime, the recall accuracy of both normal and demented elderly for a string of letters was similarly affected by the degree to which the string approximated English orthography, and recall accuracy for a string of words was affected equally in the 2 groups by the degree to which the word string obeyed syntactic and semantic rules. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emerging attributes in monkey short-term memory.

Conducted 2 experiments to examine the role of recency information and stimulus novelty and familiarity in delayed-matching-to-sample (DMTS) performance. Five female 5–8 yr old macaques (one of which was not included in Exp II) were tested on DMTS problems in which the correct and incorrect choice stimuli were both familiar, both relatively novel, or different in familiarity. Initially, novelty and familiarity exerted their influence as preferences (familiar stimuli were preferred). As more training was given, however, novelty and familiarity began to act as discriminative attributes. For example, Ss came to use the fact that the to-be-remembered stimulus was relatively novel to reject alternative choice stimuli that were more familiar. Theories of animal memory based on a single memory attribute cannot address these results. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)