Dissociating visuo-spatial and verbal working memory: It's all in the features.

Echoing many of the themes of the seminal work of Atkinson and Shiffrin (The Psychology of Learning and Motivation, 2; 89-195, 1968), this paper uses the feature model (Nairne, Memory & Cognition, 16, 343-352, 1988; Nairne, Memory & Cognition, 18; 251-269, 1990; Neath & Nairne, Psychonomic Bulletin & Review, 2; 429-441, 1995) to account for performance in working-memory tasks. The Brooks verbal and visuo-spatial matrix tasks were performed alone, with articulatory suppression, or with a spatial suppression task; the results produced the expected dissociation. We used approximate Bayesian computation techniques to fit the feature model to the data and showed that the similarity-based interference process implemented in the model accounted for the data patterns well.

Bivalent task switching and memory load: Similar costs on reaction times, different costs on concurrent timing.

Some studies suggest that time estimation involves executive control resources. This proposition was challenged recently, however, by results showing simultaneous performance of executive and timing tasks with no cost. The present study examined whether bivalent switching, in which targets may be relevant in more than one task, would interfere with timing.

Parallel effects of memory set activation and search on timing and working memory capacity.

Accurately estimating a time interval is required in everyday activities such as driving or cooking. Estimating time is relatively easy, provided a person attends to it. But a brief shift of attention to another task usually interferes with timing.

Estimating averages from distributions of tone durations.

We examined whether estimating average duration was influenced by the distribution peak location. We presented participants with samples of various tone durations and then presented comparison tone durations. Participants judged whether each comparison duration was longer than the average sample duration.

To count or not to count: the effect of instructions on expecting a break in timing.

When a break is expected during a time interval production, longer intervals are produced as the break occurs later during the interval. This effect of break location was interpreted as a result of distraction related to break expectancy in previous studies. In the present study, the influence of target duration and of instructions about chronometric counting strategies on the break location effect was examined.

[Category-specific deficits in semantic dementia: links between perception and semantic knowledge].

The nature of knowledge and its relationship with the perceptual processes are among the most central issues in the study of human cognition. Should knowledge be abstract, then semantic memory and perception should be relatively independent. On the contrary, if knowledge is sensory-dependent, then memory and perception should be very close.

Modulating the interference effect in timing with varying stimulus onset asynchrony.

The interference effect on time judgments, when subjects are also required to perform a concurrent nontemporal task, is one of the most reliable findings in the time perception literature. In the present study, the interference between a time discrimination task (short or long tone) and a digit classification task (even or odd digit) was analysed using the overlapping tasks paradigm. Reaction times in the digit task were shorter at longer values of stimulus onset asynchrony (SOA) in Experiment 1, showing a clear modulation of interference with varying the relative position of the tasks.

Concurrency benefits in the attentional blink: attentional flexibility and shifts of decision criteria.

Fundamental limitations in performing multiple tasks concurrently are well illustrated by the attentional blink (AB) deficit, which refers to the difficulty in reporting a second target (T2) when it is presented shortly after a first target (T1). Surprisingly, recent studies have shown that the AB, which is often thought of as a manifestation of capacity limitations in central processing, can be reduced when the AB task is performed simultaneously with concurrent distracting activities. In the present study, we sought to investigate whether such concurrency benefits would also be observed when the AB task was performed concurrently with a central demanding timing task.

Timing is affected by demands in memory search but not by task switching.

Recent studies suggest that timing and tasks involving executive control processes might require the same attentional resources. This should lead to interference when timing and executive tasks are executed concurrently. This study examined the interference between timing and task switching, an executive function.

Contrasting effects of interference and of breaks in interval timing.

When a break is introduced during an interval to be timed, the interval is perceived shorter as break location is delayed. This is interpreted as a result of attention sharing between timing and monitoring the source of the break signal. Similar effects and interpretations are found in another context involving interfering tasks.

Expectancy in humans in multisecond peak-interval timing with gaps.

In two experiments, the peak-interval procedure was used with humans to test effects related to gaps in multisecond timing. In Experiment 1, peak times of response distributions were shorter when the gap occurred later during the encoding of the criterion time to be reproduced, suggesting that gap expectancy shortened perceived durations. Peak times were also positively related to objective target durations.

Effects of aerobic exercise training and irbesartan on blood pressure and heart rate variability in patients with chronic obstructive pulmonary disease.

Background And Objectives: The present pilot study was undertaken to evaluate the efficacy of an aerobic exercise training (AET) program alone or combined with an antihypertensive agent (irbesartan) to reduce blood pressure (BP) and enhance heart rate variability (HRV) in chronic obstructive pulmonary disease patients.

Methods: Twenty-one patients were randomly assigned to a double-blind treatment with exercise and placebo (n=11) or exercise and irbesartan (n=10). Subjects underwent 24 h BP monitoring and 24 h electrocardiographic recording before and after the 12-week AET.

Attention sharing during timing: modulation by processing demands of an expected stimulus.

Varying the location of a nontemporal task during a time estimation task affects temporal estimates. Previous studies have also shown that manipulating the location of a stimulus to ignore may disturb timing similarly, suggesting that the effect might be independent of the processing requirements in the nontemporal task. In Experiment 1, the location of a tone varied during a 2-sec interval production; participants were asked either to ignore the tone or to discriminate its frequency.

Validity of the clinical diagnostic criteria for vascular dementia: a critical review. Part II.

This review is the second of a two-part series focusing on the validity of eight clinical criteria for vascular dementia. Sixteen studies were selected according to their purposes and quality of experimental design. The analysis revealed that criteria for vascular dementia are not interchangeable; the eight criteria sets yielded different sensitivity and specificity results, as well as marked variability in incidence, prevalence, and frequency rates.

Comparability of the clinical diagnostic criteria for vascular dementia: a critical review. Part I.

This review is the first of a two-part series focusing on the comparability of eight clinical criteria used for the diagnosis of vascular dementia: the Hachinski Ischemic Scale; the Ischemic Scale of Rosen; the criteria proposed by the Diagnostic and Statistical Manual of Mental Disorder-Third Edition (DSM-III), DSM-III-R, DSM-IV; International Classification of Diseases, 10th Revision (ICD-10); State of California Alzheimer's Disease Diagnostic and Treatment Centers (ADDTC); and the National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN). The authors discuss the critical issues related to the definition of the cognitive syndromes as well as the vascular causes and associated heterogeneity of symptomatology across these criteria.

Age-related differences in timing with breaks.

Two groups of participants differing in age were compared on a time production task during which timing was temporarily interrupted. Produced intervals lengthened with increasing delay before the break occurrence, and the effect was more pronounced in older than in younger adults. A reaction time response to the signal beginning the break period was required also.

Word frequency and the mixed-list paradox in immediate and delayed serial recall.

In free recall tasks, when low- and high-frequency items are mixed within the to-be-remembered lists, the usual recall advantage found for high-frequency words is eliminated or reversed. Recently, this mixed-list paradox has also been demonstrated for short-term serial recall (Hulme, Stuart, Brown, and Morin, 2003). Although a number of theoretical interpretations of this mixed-list paradox have been proposed, researchers have also suggested that it could simply be a result of participant-controlled strategies (M.

Temporal order in memory and interval timing: an interference analysis.

The effect of varying load in memory tasks performed during a time interval production was examined. In a first experiment, increasing load in memory search for temporal order affected concurrent time production more strongly than varying load in a spatial memory task of equivalent difficulty. This result suggests that timing uses some specific resources also required in processing temporal order in memory, resources that would not be used in the spatial memory task.

Interrupting timing in interval production and discrimination: similarities and differences.

Interruptions in human timing have been studied in the last few years using temporal production and discrimination tasks. Expecting a break shortened perceived duration in both paradigms but manipulating break duration affected time production only, suggesting that preparatory processes might not take place in time discrimination. In time production, using cues revealed that providing information about the break may modulate the effect of break expectancy.

Is the interference between memory processing and timing specific to the use of verbal material?

Increasing load in a memory task performed simultaneously with a timing task shortens perceived time, an effect that has been observed previously with memory tasks using verbal material. The present experiments examine whether two similar memory tasks, one in which verbal material is used and another one in which nonverbal material is used, would produce similar interference effects on concurrent time reproduction. In Experiment 1, the number of nonverbal stimuli (pseudo-random dot patterns) was manipulated in a memory task performed while a temporal interval to be reproduced was encoded.

Timing during interruptions in timing.

Duration and location of breaks in time interval production were manipulated in various conditions of stimulus presentation (Experiments 1-4). Produced intervals shortened and then stabilized as break duration lengthened, suggesting that participants used the break as a preparatory period to restart timing as quickly as possible at the end of the break. This interpretation was supported in Experiment 5, in which similar results were obtained with a reaction time response executed at the end of the break.

Break expectancy in duration discrimination.

Effects of break expectancy, observed previously in time production, were examined in 3 experiments using a discrimination paradigm. Participants classified a tone as being short or long. Location and duration of breaks in tone presentation were varied.

Preclinical diabetic cardiomyopathy: relation of left ventricular diastolic dysfunction to cardiac autonomic neuropathy in men with uncomplicated well-controlled type 2 diabetes.

Diabetic cardiomyopathy is an ill-defined entity. This study was designed to explore the possible association between left ventricular diastolic dysfunction (LVDD) and cardiac autonomic neuropathy (CAN) independently from metabolic control. Three groups of 10 age-matched men each with well-controlled type 2 diabetes were studied: (1) subjects with normal diastolic function, (2) subjects with LVDD characterized by impaired LV relaxation, and (3) subjects with a more severe form of LVDD characterized by a pseudonormalized pattern of LV filling.

Short-term memory and time estimation: beyond the 2-second "critical" value.

We showed previously that when time intervals around two seconds (s) are reproduced concurrently with a memory task, intervals are positively related to duration of memory processing. However, some data in research on timing as well as in memory research suggest that 2 s might be a critical duration beyond which different mechanisms or structures would support performance. This implies that the interference observed between memory processing and 2-s productions could be specific to these durations, and would not be obtained with longer durations.