Abstract: Incidental memory performance for pictures that varied along the affective dimensions of pleasantness and arousal was assessed. For both an immediate and delayed (1 year later) free-recall task, only the arousal dimension had a stable effect on memory performance: Pictures rated as highly arousing were remembered better than low-arousal stimuli. This effect was corroborated in a speeded recognition test, in which high-arousal materials encoded earlier in the experiment produced faster reaction times than their low-arousal counterparts. Pleasantness affected reaction time decisions only for pictures not encoded earlier. These results suggest that whereas both the dimensions of pleasantness and arousal are processed at initial encoding, long-term memory performance is mainly affected by arousal.

Abstract: • The present study demonstrates that schizophrenics are impaired on spatial delayed-response tasks, analogous to those that have been used to assess the working memory function of the dorsolateral prefrontal cortex in rhesus monkeys. Schizophrenic patients and two control groups, normal subjects and bipolar psychiatric patients, were tested on the oculomotor version of the memory task, a haptic version of the same task, and two control tasks: a sensory task that did not require working memory and a digit span test. The schizophrenic patients showed marked deficits relative to the two control groups in both the oculomotor and haptic delayed-response tasks. They were not, however, impaired on the digit span test, which taps verbal working memory as well as voluntary attention, and on the sensory control task, in which their responses were guided by external cues rather than by spatial working memory. These findings provide direct evidence that schizophrenics suffer a loss in representational processing and that this deficit is modality independent. These data on spatial working memory add to the growing evidence for involvement of the dorsolateral prefrontal cortex in schizophrenic disease.

Abstract: A relationship has consistently been found between measures of working memory and reading comprehension. Four hypotheses for this relationship were tested in 3 experiments. In the first 2 experiments, a moving window procedure was used to present the operation-word and reading span tasks. High- and low-span subjects did not differentially trade off time on the elements of the tasks and the to-be-remembered word. Furthermore, the correlation between span and comprehension was undiminished when the viewing times were partialed out. Experiment 3 compared a traditional experimenter-paced simple word-span and a subject-paced span in their relationship with comprehension. The experimenter-paced word-span correlated with comprehension but the subject-paced span did not. The results of all 3 experiments support a general capacity explanation for the relationship between working memory and comprehension.

Abstract: Working memory may be defined as the system for the temporary maintenance and manipulation of information, necessary for the performance of such complex cognitive activities as comprehension, learning, and reasoning. Used in this sense, the term refers to an area of research that may or may not prove to be dependent on a single coherent system. Such a system is proposed within a broad and relatively speculative overview of human memory that emphasizes the putative role of working memory. This is followed by a brief account of a particular model of working memory, and a more detailed discussion of the way in which the various subcomponents of the model relate to other aspects of memory and cognition.

Abstract: This single-blind, placebo controlled study reports on the effects of administering three acute doses of nicotine (0.4, 0.6 and 0.8 mg) subcutaneously to a group of Alzheimer's disease (DAT) patients (n=22), young adult controls (n=24), and normal aged controls (n=24). The study extends our previous findings obtained using smaller groups of subjects. Drug effects were examined on three computerised tests: the first measuring rapid visual information processing, sustained visual attention and reaction time (RVIP task); a delayed response matching to location-order task measuring sustained visual attention and visual short-term memory (DRMLO task); and a finger tapping test measuring simple reaction time (FT task). The critical flicker fusion test (CFF) was used as a measure of perception and the WAIS digit span forwards (DS), of auditory short-term memory. Tests were graded in difficulty, titrated to avoid floor and ceiling effects so that meaningful, direct comparisons between groups could be made. Nicotine significantly improved sustained visual attention (in both RVIP and DRMLO tasks), reaction time (in both FT and RVIP tasks), and perception (CFF task — both ascending and descending thresholds). Nicotine administration did not improve auditory and visual short-term memory. There were no consistent, overall patterns of difference in performance between smokers and non-smokers in the control groups, or between males and females in any group. Despite the absence of change in memory functioning, these results demonstrate that DAT patients have significant perceptual and visual attention deficits which are improved by nicotine administration. The importance of measuring multiple abilities in future drug studies is emphasized and results are discussed in terms of nicotine's actions on attention, information processing and short-term memory.

Abstract: I am honoured and pleased to have been invited to give the Bartlett Lecture. I feel a particular debt of gratitude to Bartlett as he was instrumental in founding the Unit in which I have spent most of my professional life, a Unit that embodied many of Sir Frederic’s strengths, and which I hope continues to do so. When I arrived at the Unit as a young graduate research worker from University College London, Sir Frederic had already retired as Professor of Psychology and Director of the Unit. However, he still had a room at the Unit and maintained an interest in its activities, often bringing round visitors from abroad. In my own case my research stemmed from the attempt to design a postal code, and involved a series of very un-Bartlettian experiments on the learning of nonsense syllables, a perversion that Sir Frederic seemed to tolerate with a rather grandfatherly indulgence. Were he here today, I trust that he would at least approve of the fact that my lecture will contain relatively little work on nonsense material, while noting that I have not yet managed to kick the nonsense habit completely. The topic of my lecture is a direct continuation of research on short-term memory that, although not pursued by Bartlett himself, owed much of it’s early development to Bartlett’s students, Broadbent, Brown, and Conrad. I no longer use the term “short-term memory”, but I certainly regard my research on working memory as a continuation and elaboration of an existing tradition, rather than a rejection of old models for new, such as is occasionally suggested by colleagues who refer to the “demise of short-term memory” (Crowder, 1982). Although disposable concepts may have their attractions, as will become clear, my own inclinations are towards attempting to build in durability and ease of maintenance.

Abstract: Previous studies have led to the beliefs: (1) that short-term memory is best during the night when the body temperature is at its nadir, and (2) that the circadian rhythms of short-term memory and subjective alertness are driven by oscillators independent from each other and from the body temperature cycle. Unfortunately, these conclusions, which would have major implications for understanding the organization of the human circadian timing system, are largely based on field and laboratory studies, which in many cases sampled data infrequently and/or limited data collection to normal waking hours. In order to investigate these points further, we have monitored behavioural variables in two different protocols under controlled laboratory conditions: (1) during a period of 36-60 h of sustained wakefulness; and (2) during forced desynchrony between the body temperature and sleep/wake cycles, allowing testing of non-sleep-deprived subjects at all circadian phases. Contrary to earlier findings, we report here that the circadian rhythm of short-term memory varies in parallel with the circadian rhythms of subjective alertness, calculation performance, and core body temperature under both these experimental conditions. These results challenge the notion that short-term memory is inversely linked to the body temperature cycle and suggest that the human circadian pacemaker, which drives the body temperature cycle, is the primary determinant of endogenous circadian variations in subjective alertness and calculation performance as well as in the immediate recall of meaningful material.

Abstract: Short-term memory was assessed in two groups of amnesic patients. Six patients had confirmed or suspected damage to the hippocampal formation, and six patients had diencephalic damage as a result of alcoholic Korsakoff's syndrome. Verbal short-term memory was evaluated with seven separate administrations of the standard digit span test in order to obtain a precise measure of short-term memory. Nonverbal short-term memory was evaluated with four tests that assessed apprehension, retention, and the ability to manipulate nonverbal material--all within the span of immediate memory. One of these four tests assessed short-term memory for spatial location. Patients with damage to the hippocampal formation had a digit span equivalent to that of control subjects and also performed normally on the four tests of nonverbal short-term memory. The patients with Korsakoff's syndrome had a marginally low digit span and performed poorly on three of the four nonverbal tasks, a finding consistent with the deficits in attention and visuospatial processing previously described for this patient group. These deficits are likely due to the frontal lobe atrophy typically associated with Korsakoff's syndrome, rather than to diencephalic damage. The results support the view that short-term (immediate) memory, including short-term spatial memory, is independent of the hippocampus.

Abstract: This study investigates whether individual differences in working memory are related to a general system and whether the predictability of working memory to academic achievement is enhanced under dynamic testing conditions. Experiment 1 correlated 11 working memory tasks with shortterm memory and achievement measures. Convergent and discriminant validity for the working memory measures was established. Although a confirmatory factor analysis supported the notion that the working memory tasks reflect 2 operations, these operations produced similar correlational patterns to achievement. Experiment 2 supported a 2-factor model under dynamic testing procedures, and those procedures contribute significant variance to reading performance

Abstract: A 3-group reading-level design was used to investigate phonological analysis, verbal working memory, and pseudoword reading performance in less skilled fourth-grade readers. Children were given phonological oddity tasks assessing their sensitivity to subsyllabic and phonemic units, together with standardized tests of verbal working memory and pseudoword reading. Less skilled fourth-grade readers performed lower than both chronological age and reading-level controls on the phonological oddity and pseudoword reading tests. Less skilled fourth-grade readers performed at the same level as skilled second-grade readers on a test of verbal working memory. Skilled fourth-grade readers scored higher than both other groups on this test. Correlational analyses were consistent with the view that phonological analysis skills contribute more strongly than verbal working memory skills to children's decoding abilities.

Abstract: Two experiments were carried out to test the hypothesis that verbal recoding of visual stimuli in short-term memory influences long-term memory encoding and impairs subsequent mental image operations. Easy and difficult-to-name stimuli were used. When rotated 90 degrees counterclockwise, each stimulus revealed a new pattern consisting of two capital letters joined together. In both experiments, subjects first learned a short series of stimuli and were then asked to rotate mental images of the stimuli in order to detect the hidden letters. In Experiment 1, articulatory suppression was used to prevent subjects from subvocal rehearsal when learning the stimuli, whereas in Experiment 2, verbal labels were presented with each stimulus during learning to encourage a reliance on the verbal code. As predicted, performance in the imagery task was significantly improved by suppression when the stimuli were easy to name (Experiment 1) but was severely disrupted by labeling when the stimuli were difficult to name (Experiment 2). We concluded that verbal recoding of stimuli in short-term memory during learning disrupts the ability to generate veridical mental images from long-term memory.

Abstract: Velocity discrimination thresholds for drifting luminance gratings were measured as a function of the time interval between test and reference gratings, using a two-interval, forced-choice procedure. Discrimination thresholds, expressed as Weber fractions (delta V/V), were independent of interstimulus intervals (ISIs) ranging from 1-30 s, demonstrating perfect short-term retention of velocity information. When a third grating was briefly presented halfway through a 10-s ISI, memory masking was observed. Discrimination thresholds in memory masking were unaffected by maskers of the same velocity but increased by 100% when test and masker velocity differed by a factor of 2. The results are interpreted with reference to a model where the short-term memory for simple stimulus attributes is assumed to be organized in terms of arrays of memory stores linked in a lateral inhibitory network. Language: en

Abstract: Summary Two complimentary topics are of special interest in the study of cognitive skills, first the involvement of working memory resources in successful performance, and second the role of automaticity in the component processes of such performance. While these questions figure prominently in contemporary cognitive research, they have only recently begun to receive direct investigation in the area of mental arithmetic. In this chapter, we review the existing research that bears on these issues, then present two experiments. Experiment 1 focused on the deployment of working memory resources during arithmetic processing, using a standard dual-task method. Experiment 2 investigated automatic and conscious processing as revealed by a priming task. The results of both experiments are viewed in terms of the basic problem difficulty variable, and the relationship between this variable and manipulations that tap automatic and effortful aspects of performance. The chapter concludes with some remarks on the central construct of problem difficulty.

Abstract: Female Sprague-Dawley rats were injected with the noncompetitive N-methyl-D-aspartate (NMDA) antagonist MK-801 or saline 30 min before daily testing in spatial working memory (WM) and reference memory (RM) procedures in an 8-arm radial maze. MK-801 impaired RM and WM acquisition but not performance when rats were trained to criterion before drug administration. Neither a 2-hr nor a 4-hr delay between the first and last 2 correct WM choices impaired long-term WM. MK-801 impaired WM performance in trained rats only when rats were tested in a new environment. Thus, 2 mechanisms may be required for relational memory: an NMDA-dependent mechanism for acquiring long-term spatial representations and an NMDA-insensitive mechanism for operating on these stored representations.

Abstract: We recorded event-related brain potentials (ERPs) from 13 patients with chronic fatigue syndrome (CFS) and 13 matched normal controls. To assess attentional and memory deficits in CFS patients, we used a short-term memory task in which events occurred in different spatial locations and the patients made a rapid-response (RT) when a letter in a relevant location matched a letter in the prememorized set (Attention paradigm). Time-on-task effects on the ERP and behavioral measures were assessed over the 2 1/4-hour duration of this task. Both groups also performed a visual Oddball paradigm, with an RT, before and after the Attention paradigm. The patients' RTs were much more variable and, in nine of 13 cases, slower than the mean RT of the controls in both paradigms. The patients' memory performance was not significantly different from that of the controls and there were no group differences in the overall amplitude, latency, or scalp distribution of the N1, P2, N2, or P300 components of the ERP in either paradigm. The ERP and performance data from both paradigms suggest that perceptual, attentional, and short-term memory processes were unaffected in CFS patients and that the differences were limited to response-related processes.

Abstract: Based on the finding that increasing stimulus presentation rate can increase short-term memory (STM) span, reading rate was accelerated in a series of experiments that demonstrated substantial gains in reading accuracy and comprehension. The present investigation tested the hypothesis that comprehension gains in fast-paced reading are attributable primarily to changes in STM functioning. A series of standard STM-sensitive tasks were administered in both self-paced and fast-paced reading conditions. The magnitude and relative specificity of effects evident in fastpaced reading confirmed the hypothesis. Several alternative hypotheses were rejected

Abstract: In this chapter recent research on the psychology of short-term memory is discussed. The chapter begins with evidence which suggests that phonological short-term memory is indeed required both for syntactic processing and for first and second language acquisition. Current psychological models of short-term memory, and their explanation for the reduced memory span size that is observed in a less familiar language, are then summarised. These accounts are criticised, and the results of several studies that test an alternative explanation for the reduced memory span observed in a second language are described. It is concluded that reduced short-term memory capacity can arise because of the lack of strong phonological lexical representations for second language items in long term memory.

Abstract: The action of the cerebral cholinergic system seems to be important for remembering events over short time intervals. We decided to test this hypothesis in the rat by developing an original model of short term memory based on the olfactory sensory modality which is a major determinant in the animal behaviour. The principle of the experiment was a “delayed match-to-sample” test performed in a classical T maze divided into two compartments. In the first compartment, rats received an odorant stimulation, then, in the second, they had to discriminate between the two arms odorized differently. To receive a food reinforcement, the animals had to enter the arm signaled by the odor presented in the first part of the maze. The test was performed with (Short-term memory condition) or without (Immediate memory condition) a variable delay between the first odor sampling and the discrimination task. Both tests were performed with control and scopolamine-treated animals (0.5, 0.125 and 0.0625 mg/kg IP). An injection of scopolamine (0.5 mg/kg) impaired performances, even when no retention of the odor was required. However, lower doses (0.125, 0.0625 mg/kg) selectively altered performances in the short term memory condition. These results suggest that intact muscarinic transmission is required for an olfactory cue to be used over a short time after its presentation.

Abstract: Young and elderly adults' performance was compared on the Landmark Selection Task, designed to assess perceptual selection, and the Scrambled Route Task, designed to assess temporospatial integration. Age-related performance decrements were found on both tasks. Subjects' scores on psychometric tests hypothesized as involving some of the same processes as these experimental tasks yielded positive correlations to measures of task performance. Unexpectedly, self-estimates of wayfinding and distance estimation skills were negatively correlated to experimental task performance for elderly adults. Results were discussed in the context of declines in the effectiveness of selective attention, which is considered critical to perceptual selection, and in the proficiency of working memory, which is considered central to temporospatial integration.

Abstract: Some patients with phonological short-term memory deficits also show deficits in speech perception. This study investigated the possibility that these patients' short-term memory pattern derives fr...