Stage independence in a memory-search task.

Performed a memory-search task in which the presented items were consonants belonging to the memory set, other consonants, and a blank stimulus (i.e., an empty stimulus field). 12 undergraduates served as Ss. Compatible with a hypothesis based on S. Sternberg's 1969 model predicting independence of search and nonsearch stages, it was found that as the size of the memory set increased, reaction time to members of the memory set and nonmember consonants increased at equal rates, while reaction time to the blank stimulus was independent of size of the memory set. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

P300 latency and memory span development.

The rapid increase of memory span with development has been attributed to increases in the efficiency with which children can process the items to be remembered. To test this hypothesis, WAIS Digit Span and latency from the P300 component of the event-related brain potential—a measure of stimulus evaluation time independent of response production—were obtained from 24 5–14 yr olds and 24 20–40 yr olds. Increases in digit span were associated with decreases in peak latency for children but not for adults. This finding was obtained even when S age was statistically removed, and it suggests that immediate memory development is tightly coupled with decreases in speed of stimulus identification. Implications for theories of memory development are discussed. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of retrieval in schizophrenic memory deficit.

To distinguish between information that is unavailable or inaccessible in the schizophrenic's memory store, 48 schizophrenics and 48 normals learned 3 lists of categorized words. The lists were either cued or not cued at recall. Demographic and pretest measures validated the diagnosis of schizophrenia and indicated no significant differences between the experimental groups on age, education, intelligence, or categorizing ability. Results indicate that under conditions where the input did not exceed the limits of immediate memory span, schizophrenic memory deficit could be explained in terms of an "inaccessibility" of items due to a retrieval dysfunction. Under conditions where input exceeded these limits, the recall analysis was suggestive of an "unavailability" of items in the memory store. It is concluded that schizophrenics suffer deficits throughout the information processing system rather than at any specific stage. The locus of breakdown was dependent on the task demands of the experimental situation. (French summary) (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of aging, distraction, and response pressure on the binding of actors and actions.

Two experiments provide evidence for an age-related deficit in the binding of actors with actions that is distinct from binding deficits associated with distraction or response pressure. Young and older adults viewed a series of actors performing different actions. Participants returned 1 week later for a recognition test. Older adults were more likely than young adults to falsely recognize novel conjunctions of familiar actors and actions. This age-related binding deficit occurred even when older adults could discriminate old items from new items just as well as could young adults. Young adults who experienced distraction or time pressure also had difficulty discriminating old items from conjunction items, but this deficit was accompanied by a deficit at discriminating old and new items. These results suggest that distraction and response pressure lead to deficits in memory for stimulus components, with any deficits in binding ability commensurate with these deficits in component memory. Aging, in turn, may lead to binding difficulties that are independent of attention-demanding executive processes involved in maintaining individual stimulus components in working memory, likely reflecting declines in hippocampally mediated associative processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive organization of impressions: Effects of incongruency in complex representations.

Two experiments investigated the organization in memory of expectancy-congruent and expectancy-incongruent information pertaining to multiple trait concepts in an impression-formation task. In Experiment 1, when multiple trait concepts were represented in the information describing the target person, both congruent and incongruent items reflecting the same trait concept were stored together and were directly associated in memory, and both types of items were recalled equally well. In Experiment 2, when only one trait concept was represented in the information, incongruent items were recalled with higher probability than congruent items, and the latter were not directly associated in memory. Results suggest that with increasing categorical complexity of stimulus information, processes are invoked that do not occur in simpler impression-formation contexts. Implications for theoretical models of person memory are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensory registration and informational persistence.

The view of iconic memory as a precategorical, high-capacity, quickly decaying visible memory has recently come under attack (e.g., M. Coltheart, 1980). Distinctions have been drawn between visible persistence, or the phenomenal trace of an extinguished stimulus, and informational persistence, knowledge about the visual properties of the stimulus. Two alternative conceptions of informational persistence were tested in 3 experiments with 13 university students and the present authors. One conception is that visual information persists in a visual memory that begins at stimulus offset and lasts for 150–300 msec, independently of exposure duration. The 2nd conception is that informational persistence arises from a nonvisual memory that contains spatial coordinates for displayed items along with identity codes for those items. In the experiments, 3?×?3 letter arrays were presented for durations ranging from 50 to 500 msec. A single character mask presented at varying intervals after array offset cued report of an entire row of the array. Comparison of the cued row's masked and unmasked letters revealed that spatially specific visual (i.e., maskable) information persisted after stimulus offset, regardless of exposure duration. This result favors the visual conception of informational persistence. There was also support, however, for the nonvisual conception: Accuracy increased and item intrusion errors decreased as stimulus duration increased. Implications for models of informational persistence and for transsaccadic integration during reading are discussed. (47 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Orienting attention in visual working memory reduces interference from memory probes.

Given a changing visual environment, and the limited capacity of visual working memory (VWM), the contents of VWM must be in constant flux. Using a change detection task, the authors show that VWM is subject to obligatory updating in the face of new information. Change detection performance is enhanced when the item that may change is retrospectively cued 1 s after memory encoding and 0.5 s before testing. The retro-cue benefit cannot be explained by memory decay or by a reduction in interference from other items held in VWM. Rather, orienting attention to a single memory item makes VWM more resistant to interference from the test probe. The authors conclude that the content of VWM is volatile unless it receives focused attention, and that the standard change detection task underestimates VWM capacity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When recognition memory fails: The use of an elimination strategy by young children.

Two experiments explored the response strategies of young children in the case of the evident failure of recognition memory. 20 4-yr-olds and 20 7-yr-olds were shown a series of pictorial paired associates. At test, Ss had to choose from a set of 4 items the response that had been paired with a particular stimulus during study. The response set consisted of 3 response items paired with a stimulus during study, and 1 new item. In addition to testing the pairs seen during study, 4 new stimulus–response pairs were tested in the same manner. Response choices for these new stimuli, as well as for the stimuli seen during study, allowed an assessment of the strategies used by Ss in the situation where recognition memory has apparently failed. Results show that Ss of both ages employed a reasoning-by-exclusion elimination strategy in responding to the stimuli. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of subliminal stimulation upon autonomic and verbal behavior.

Using the subception hypothesis of Lazarus and McCleary, 2 hypotheses pertaining to the effect upon verbal and autonomic behavior of subliminal visual stimulation were tested. The hypotheses stated that: response latencies and GSRs would be determined by the affective value of the stimuli, and the verbal guesses made during subliminal stimulation would be associations to the stimulus items. 7 Ss were used, and after subliminal presentation of the stimuli, each S was presented with his responses and asked to match them against the stimulus items. The part of the hypothesis pertaining to response latencies was not supported, but the part pertaining to GSRs was confirmed. The second hypothesis, likewise, was confirmed. 18 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrieval selectivity in memory-based impression judgments.

Judgments about others are often based on memory for information about the persons being judged. Three studies with a total of 92 undergraduates are reported that used decision time to determine what information Ss selectively recall when they make memory-based person judgments. Each study employed a sequential judgment paradigm in which an S first made an impression judgment about a person on one dimension while stimulus information was continuously available. Immediately therafter, the S made a 2nd judgment about the same person on a different dimension without the stimulus information being available. It is concluded that Ss' memory-based judgments were based on memory for their 1st impression judgments combined with a selective memory search for negative stimulus information. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory for multiple visual ensembles in infancy.

The number of individual items that can be maintained in working memory is limited. One solution to this problem is to store representations of ensembles that contain summary information about large numbers of items (e.g., the approximate number or cumulative area of a group of many items). Here we explored the developmental origins of ensemble representations by asking whether infants represent ensembles and, if so, how many at one time. We habituated 9-month-old infants to arrays containing 2, 3, or 4 spatially intermixed colored subsets of dots, then asked whether they detected a numerical change to one of the subsets or to the superset of all dots. Experiment Series 1 showed that infants detected a numerical change to 1 of the subsets when the array contained 2 subsets but not 3 or 4 subsets. Experiment Series 2 showed that infants detected a change to the superset of all dots no matter how many subsets were presented. Experiment 3 showed that infants represented both the approximate number and the cumulative surface area of these ensembles. Our results suggest that infants, like adults (Halberda, Sires, & Feigenson, 2006), can store quantitative information about 2 subsets plus the superset: a total of 3 ensembles. This converges with the known limit on the number of individual objects infants and adults can store and suggests that, throughout development, an ensemble functions much like an individual object for working memory. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Short term memory for numerousness in schizophrenic young adults

The short term memory of schizophrenics for random dot patterns was examined by a delayed comparison procedure. In experiment 1, the 10 schizophrenics and 10 normals compared a fixed dot pattern (standard) with a variable dot pattern (compairson) appearing 2 or 8 seconds later and decided whether the comparison stimulus had "more" or "less" dots than the standard. Memory strength, indexed by the d' value of signal-detection theory, showed neither group difference nor decay over time. In experiment 2, the interstimulus interval was filled with an unjudged dot pattern (storage interference), and the standard stimulus followed the variable comparison stimulus (encoding difficulty). The memory strength of 17 schizophrenics and 17 normals was severely impaired, and their memory strength weakened over time, but again, no group differences were found. In both experiments, the two groups showed a strong bias (beta) in underestimating the first (to-be-remembered) stimulus. It was concluded that schizophrenics' short term perceptual memory for nonverbal stimuli remains good.     

Dream recall and dream recall failure: An arousal-retrieval model.

Proposes an arousal/retrieval model to account for difficulties in sleep learning and dream recall. The model is based on 2-stage memory theory, which assumes that information processing in a short-term memory store facilitates subsequent retrieval from long-term memory storage. It is proposed that the effectiveness of processing of target material is impaired during sleep. Thus, dreams and information contained in stimulus presentations to a sleeping person very likely can only be retrieved if an awakening occurs during the life of the short-term memory trace. It is further proposed that experiences occurring during or shortly after awakening compete with the target material for space in the limited-capacity processing system, with the most salient of the set favored in the competition. Interference and repression effects are assumed as additional factors in retrieval from long-term storage. (11/2 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Variations in Intensity and Frequency Moderate the Facilitative Effects of a Complex Rhythm Stimulus on Long-Term Memory Consolidation in the Day-Old Chick (Callus gallus).

The authors have previously shown that exposure to 1 min of a complex, but not an isochronous, rhythm stimulus facilitates long-term memory consolidation in chicks (Gallus gallus) trained on a passive-avoidance task (S. R. Toukhsati & N. S. Rickard, 2001). The acoustic parameters of this stimulus were explored further in the current study. Retention was found to be best facilitated when the complex rhythm stimulus was presented at intensities between 5 and 15 dBA above background laboratory noise levels and at a frequency of 1 kHz. Removal of an accent from the stimulus did not moderate the effect. These findings provide confirmation that memory in an avian species can be facilitated by exposure to a complex rhythm stimulus and suggest that pattern repetition may be an important feature of this effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time-related decay or interference-based forgetting in working memory?

The time-based resource-sharing model of working memory assumes that memory traces suffer from a time-related decay when attention is occupied by concurrent activities. Using complex continuous span tasks in which temporal parameters are carefully controlled, P. Barrouillet, S. Bernardin, S. Portrat, E. Vergauwe, & V. Camos (2007) recently provided evidence that any increase in time of the processing component of these tasks results in lower recall performance. However, K. Oberauer and R. Kliegl (2006) pointed out that, in this paradigm, increased processing times are accompanied by a corollary decrease of the remaining time during which attention is available to refresh memory traces. As a consequence, the main determinant of recall performance in complex span tasks would not be the duration of attentional capture inducing time-related decay, as Barrouillet et al. (2007) claimed, but the time available to repair memory traces, and thus would be compatible with an interference account of forgetting. The authors demonstrate here that even when the time available to refresh memory traces is kept constant, increasing the processing time still results in poorer recall, confirming that time-related decay is the source of forgetting within working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognition memory for novel stimuli: The structural regularity hypothesis.

Early studies of human memory suggest that adherence to a known structural regularity (e.g., orthographic regularity) benefits memory for an otherwise novel stimulus (e.g., G. A. Miller, 1958). However, a more recent study suggests that structural regularity can lead to an increase in false-positive responses on recognition memory tests (B. W. A. Whittlesea & L. D. Williams, 1998). In the present study the authors attempted to identify the circumstances under which structural regularity benefits old-new discrimination and those under which it leads to an increase in false-positive responses. The highly generalizable tendency shown here is for structural regularity to benefit old-new discrimination. The increase in false-positive responses for structurally regular novel items may be limited to situations in which regularity is confounded with similarity to studied items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Short-term implicit memory for words and nonwords.

A short-term implicit memory effect is reported and interpreted as arising within the word recognition system. In Experiment 1, repetition priming in lexical decision was determined for low-frequency words and pseudowords at lags of 0, 1, 2, 3, 4, 5, 9, and 23 intervening items. For words, a large short-term priming component decayed rapidly but smoothly over the first 3 items (8 s) to a stable long-term value. For nonwords, priming dropped to the long-term value with a single intervening item. This Lag x Lexicality interaction was replicated with a naming task in Experiment 2 and with high-frequency words in Experiment 3. Word frequency affected long-term priming but not the size or decay rate of short-term priming, dissociating the two repetition effects. In Experiment 4, an old-new decision task was used to test explicit memory. Parallel word and nonword decay patterns were found, dissociating short-term priming from explicit working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of levels of processing on recall from working memory and delayed recall tasks.

Recent research in working memory has highlighted the similarities involved in retrieval from complex span tasks and episodic memory tasks, suggesting that these tasks are influenced by similar memory processes. In the present article, the authors manipulated the level of processing engaged when studying to-be-remembered words during a reading span task (Experiment 1) and an operation span task (Experiment 2) in order to assess the role of retrieval from secondary memory during complex span tasks. Immediate recall from both span tasks was greater for items studied under deep processing instructions compared with items studied under shallow processing instructions regardless of trial length. Recall was better for deep than for shallow levels of processing on delayed recall tests as well. These data are consistent with the primary-secondary memory framework, which suggests that to-be-remembered items are displaced from primary memory (i.e., the focus of attention) during the processing phases of complex span tasks and therefore must be retrieved from secondary memory. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

An oscillatory short-term memory buffer model can account for data on the Sternberg task

A limited number (7 +/- 2) of items can be held in human short-term memory (STM). We have previously suggested that observed dual (theta and gamma) oscillations could underlie a multiplexing mechanism that enables a single network to actively store up to seven memories. Here we have asked whether models of this kind can account for the data on the Sternberg task, the most quantitative measurements of memory search available. We have found several variants of the oscillatory search model that account for the quantitative dependence of the reaction time distribution on the number of items (S) held in STM. The models differ on the issues of (1) whether theta frequency varies with S and (2) whether the phase of ongoing oscillations is reset by the probe. Using these models the frequencies of dual oscillations can be derived from psychophysical data. The derived values (ftheta = 6-10 Hz; fgamma = 45-60 Hz) are in reasonable agreement with experimental values. The exhaustive nature of the serial search that has been inferred from psychophysical measurements can be plausibly explained by these oscillatory models. One argument against exhaustive serial search has been the existence of serial position effects. We find that these effects can be explained by short-term repetition priming in the context of serial scanning models. Our results strengthen the case for serial processing and point to experiments that discriminate between variants of the serial scanning process.