40,762 research outputs found

    Attention to attributes and objects in working memory

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    It has been debated on the basis of change-detection procedures whether visual working memory is limited by the number of objects, task-relevant attributes within those objects, or bindings between attributes. This debate, however, has been hampered by several limitations, including the use of conditions that vary between studies and the absence of appropriate mathematical models to estimate the number of items in working memory in different stimulus conditions. We re-examined working memory limits in two experiments with a wide array of conditions involving color and shape attributes, relying on a set of new models to fit various stimulus situations. In Experiment 2, a new procedure allowed identical retrieval conditions across different conditions of attention at encoding. The results show that multiple attributes compete for attention, but that retaining the binding between attributes is accomplished only by retaining the attributes themselves. We propose a theoretical account in which a fixed object capacity limit contains within it the possibility of the incomplete retention of object attributes, depending on the direction of attention

    Feature-Based Change Detection Reveals Inconsistent Individual Differences in Visual Working Memory Capacity

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    Visual working memory (VWM) is a key cognitive system that enables people to hold visual information in mind after a stimulus has been removed and compare past and present to detect changes that have occurred. VWM is severely capacity limited to around 3–4 items, although there are robust individual differences in this limit. Importantly, these individual differences are evident in neural measures of VWM capacity. Here, we capitalized on recent work showing that capacity is lower for more complex stimulus dimension. In particular, we asked whether individual differences in capacity remain consistent if capacity is shifted by a more demanding task, and, further, whether the correspondence between behavioral and neural measures holds across a shift in VWM capacity. Participants completed a change detection (CD) task with simple colors and complex shapes in an fMRI experiment. As expected, capacity was significantly lower for the shape dimension. Moreover, there were robust individual differences in behavioral estimates of VWM capacity across dimensions. Similarly, participants with a stronger BOLD response for color also showed a strong neural response for shape within the lateral occipital cortex, intraparietal sulcus (IPS), and superior IPS. Although there were robust individual differences in the behavioral and neural measures, we found little evidence of systematic brain-behavior correlations across feature dimensions. This suggests that behavioral and neural measures of capacity provide different views onto the processes that underlie VWM and CD. Recent theoretical approaches that attempt to bridge between behavioral and neural measures are well positioned to address these findings in future work

    New perspectives on binding in visual working memory.

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    How does visual working memory (WM) store the binding between different features of a visual object (like colour, orientation, and location), and does memorizing these bindings require additional resources beyond memorizing individual features? These questions have traditionally been addressed by comparing performance across different types of change detection task. More recently, experimental tasks such as analogue (cued) recall, combined with analysis methods including Bayesian hypothesis testing and formal model comparison, have shed new light on the properties of WM. A significant new perspective is that noise in neural representation limits the precision of recall, and several recent models incorporate this view to account for failures of binding in WM. We review the literature on feature binding with a focus on these new developments and discuss their implications for the interpretation of classical findings

    The Small Number System

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    I argue that the human mind includes an innate domain-specific system for representing precise small numerical quantities. This theory contrasts with object-tracking theories and with domain-general theories that only make use of mental models. I argue that there is a good amount of evidence for innate representations of small numerical quantities and that such a domain-specific system has explanatory advantages when infants’ poor working memory is taken into account. I also show that the mental models approach requires previously unnoticed domain-specific structure and consequently that there is no domain-general alternative to an innate domain-specific small number system

    A psychology literature study on modality related issues for multimodal presentation in crisis management

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    The motivation of this psychology literature study is to obtain modality related guidelines for real-time information presentation in crisis management environment. The crisis management task is usually companied by time urgency, risk, uncertainty, and high information density. Decision makers (crisis managers) might undergo cognitive overload and tend to show biases in their performances. Therefore, the on-going crisis event needs to be presented in a manner that enhances perception, assists diagnosis, and prevents cognitive overload. To this end, this study looked into the modality effects on perception, cognitive load, working memory, learning, and attention. Selected topics include working memory, dual-coding theory, cognitive load theory, multimedia learning, and attention. The findings are several modality usage guidelines which may lead to more efficient use of the user’s cognitive capacity and enhance the information perception

    Limitations of Human Visual Working Memory

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    The present empirical study investigates limitations of human visual working memory (VWM). The experiments of the present work involve the experimental paradigm of change detection using simple geometrical objects in the form of rectangles of different colour, length, and orientation. It can be shown, that a limited performance in the temporary storage of visual information has multiple sources. Limitations of VWM can be attributed to a limited capacity or a limited duration, but also to limitations in retrieval, which so far has found only little attention. Key findings of the present study show, that a capacity limitation cannot be described by a simple and generally valid size of the store. It is in fact generally acknowledged that the capacity limitation of VWM is object-based, which means that the capacity can roughly be determined by the number of visual objects. However, it could be shown that the complexity of the objects has an influence on memory performance: Experimental evidence shows, e.g., that memory performance decreases, when an object is characterized not only by one feature (e.g. colour), but by a number of features (e.g. colour, orientation and size). The results are explained by increased storage demands for the binding of the features. Other key findings of the present study relate to the process of retrieval of information from VWM. For example, an asymmetric performance pattern could be observed: In a change detection task a memory performance was observed that corresponds to a capacity of 3 - 4 objects. In contrast a drastic decrease of performance corresponding to a capacity of only 1 object was observed, when the task was to find a matching item among changed distractors. These results lead to the idea of a change signal, by which the empirical data can be explained. The change signal is elicited by a local mismatch between the information stored in VSTM and perceptual online information. The retrieval process is efficient, when the change signal can be used in the memory task. However, retrieval is extremely limited, when in the presence of multiple changes a less efficient strategy has to be applied. In the course of the present study, moreover, it became evident that there are various links between VWM processes and visual attention. Visual attention is probably crucial for feature binding in VWM. In retrieval the change signal probably involves mechanisms of visual attention. The present study could, therefore, contribute to a clarification of the relation between VWM and visual attentionDie vorliegende empirische Arbeit untersucht Begrenzungen des menschlichen visuellen Kurzzeitgedächtnisses (VKZG). In den Experimenten dieser Arbeit wird unter Verwendung von visuell einfachen geometrischen Figuren in Form von Rechtecken verschiedener Farbe, Länge und Orientierung das experimentelle Paradigma der Veränderungsdetektion eingesetzt. Es wird gezeigt, dass eine begrenzte Gedächtnisleistung bei der kurzfristigen Speicherung visueller Information unterschiedliche Ursprünge hat. Diese Ursprünge können sowohl in einer begrenzten Kapazität und in einer begrenzten Speicherdauer liegen, jedoch auch in den Bedingungen des Abrufs, was bislang in der Forschung nur wenig Beachtung gefunden hat. Wesentliche Befunde der vorliegenden Arbeit zeigen, dass die Limitierung in der Speicherkapazität nicht durch eine einfache und allgemeingültige Angabe der Größe des Speichers zu beschreiben ist. Zwar ist es als erwiesen anzunehmen, dass die Kapazitätslimitierung des VKZG objektbasiert ist, d. h. dass sich die Kapazität des VKZG grob durch die Anzahl der zu speichernden visuellen Objekte bestimmen lässt. Jedoch spielt auch die Komplexität dieser Objekte eine Rolle: Die empirischen Ergebnisse zeigen, dass die Gedächtnisleistung abnimmt, wenn ein Objekt nicht nur durch ein Merkmal (z.B. Farbe) charakterisiert ist, sondern durch mehrere Merkmale (z.B. Farbe, Orientierung und Länge). Diese Befund wird mit einem erhöhten Speicheraufwand für die Merkmalsbindung erklärt. Andere zentrale Befunde dieser Arbeit wurden im Zusammenhang mit der Untersuchung des Abrufs von Informationen aus dem VKZG erhoben. So konnte z.B. eine asymmetrische Gedächtnisleistung beobachtet werden: Wurde das experimentelle Paradigma der Veränderungsdetektion eingesetzt, entsprach die Gedächtnisleistung einer Kapazität von etwa 3 - 4 Objekten. Im Gegensatz dazu wurde ein drastischer Leistungsabfall, entsprechend einer Kapazität von 1 Objekt, beobachtet, wenn unter Abwandlung des Paradigmas nun nicht ein verändertes, sondern ein unverändertes Objekt das Zielobjekt unter sich geänderten Distraktoren war. Aufgrund der Ergebnisse wird die Idee eines Veränderungssignals entwickelt, wodurch die Befunde erklärt werden können. Das Veränderungssignal wird durch eine lokale Inkongruenz zwischen im VKZG gespeicherter und wahrgenommener Information hervorgerufen. Wenn ein solches Veränderungssignal zur Lösung der Gedächtnisaufgabe ausgenutzt werden kann, ist der Abruf effektiv. Der Abruf ist dagegen extrem limitiert, wenn aufgrund multipler Änderungen eine weniger effektive Strategie zur Lösung der Aufgabe eingesetzt werden muss. Im Zuge der vorliegenden Arbeit haben sich darüber hinaus vielfältige Zusammenhänge zwischen Prozessen des VKZG und der visuellen Aufmerksamkeit gezeigt. So ist visuelle Aufmerksamkeit vermutlich für die Merkmalsbindung im VKZG wichtig. Und auch beim Abruf ist visuelle Aufmerksamkeit beteiligt, indem nämlich die Verarbeitung des postulierten Veränderungssignals Mechanismen der visuellen Aufmerksamkeit involviert. Die vorliegende Dissertation konnte auf diese Weise Hinweise zur Klärung der Zusammenhänge von VKZG und visueller Aufmerksamkeit liefer

    The cognitive neuroscience of visual working memory

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    Visual working memory allows us to temporarily maintain and manipulate visual information in order to solve a task. The study of the brain mechanisms underlying this function began more than half a century ago, with Scoville and Milner’s (1957) seminal discoveries with amnesic patients. This timely collection of papers brings together diverse perspectives on the cognitive neuroscience of visual working memory from multiple fields that have traditionally been fairly disjointed: human neuroimaging, electrophysiological, behavioural and animal lesion studies, investigating both the developing and the adult brain

    The influence of auditory and contextual representations on visual working memory

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