Search Results

This chapter reviews research examining visual memory for complex, natural environments. It is divided into two main sections. The first concerns the use of visual memory to construct online representations of natural scenes (i.e., the representation produced as one is actively viewing a scene). The second concerns longer-term scene memory stored after a scene is no longer in view.

This chapter reviews the evidence supporting the view that representations are retained and combined across eye movements and over extended time. In particular, it considers representations that are generated over three time periods: across fixations (transsaccadic memory), over multiple fixation-saccade cycles (active online scene memory), and over the longer term (long-term scene memory). It highlights recent experiments on saccadic eye movements and visual memory. It argues that a composite scene representation that includes relatively detailed (although not sensory or iconic) visual information is generated and retained in memory across eye movements and over time as a natural consequence of active, dynamic scene perception.

This chapter discusses neuropsychological disorders of visual short-term memory (VSTM) and the importance of these disorders for theories of VSTM. It emphasizes the role of VSTM not only in “bottom-up” processes (forming a memory for new material from the environment) but also in “top-down” processing, as when visual images are formed from material from long-term memory (LTM). It is argued that just as VSTM is involved when we need to remember new visual input, so visual imagery recruits VSTM, which then serves as a medium for retrieving stored visual memories. Thus, the same processes (and brain regions) that play a part in typical laboratory studies of VSTM using relatively simple visual displays may also be involved when people make judgments about the visual characteristics of objects retrieved from LTM.

Visual stimuli not only remain visible for some time after their physical offset, but information about their characteristics also persists; that is, not only does something that looks like the physical stimulus continue to persist for a brief time after stimulus offset, but information can also be extracted from the stimulus for a brief time after its offset in much the same way as when the stimulus was physically present. This latter type of persistence is usually called informational persistence. Visible persistence and informational persistence reflect related but different aspects of visual sensory memory. This chapter discusses the evidence behind this assertion and describes the current conception of these phenomena.

This chapter discusses visual short-term memory (VSTM) system. It compares VSTM system with visual long-term memory system. It then discusses the measurement of VSTM, the storage capacity of VSTM, the reasons why VSTM capacity is limited, the nature of VSTM representations, VSTM processes, and the functions of the VSTM process.

This chapter summarizes the various visual memory systems that are discussed in this book, focusing on the nature of the representations used by these systems, their temporal dynamics, their neutral substrates, and their functional role in visually guided behavior. It discusses the definition of visual memory. It then describes the three main subsystems of visual memory: visual sensory memory, visual short-term memory (VSTM), and long-term memory (LTM).

The ability to hold visual information in mind beyond the duration of the initial sensory stimulation critically underpins many higher-level cognitive functions. In particular, visual short-term memory (VSTM) provides the perceptual continuity that is necessary for visual information to guide behavior across short temporal delays. This chapter explores how the mechanisms of attention optimize VSTM. First, it considers how top-down attention biases VSTM encoding to favor information that is most likely to be relevant to behavior. Next, it looks at more recent evidence that top-down attention can also bias representations already stored within VSTM. Flexible allocation of attention within VSTM enables the visual system to prioritize and update stored representations to accommodate changing task demands.

This chapter examines the traumatic and pleasurable aspects of war. Visual culture — films, art, war writing, and surgical literature — influenced the ‘cultural memory’ of the ‘war-wrecked’ body, to which reconstruction responded. The chapter illuminates the context in which painful narratives and violent images resonated from the individual to society through cultural forms. It questions the use of trauma theory in comprehending reactions to war in the past. Trauma theory does not account for the ‘pleasure culture of war’ and the curiosity around the wounded body. The chapter argues that the ‘culture shock’ of modern warfare visualized violence and suffering, and this was part of the search for meaning. Audiences found visual culture informative, comforting, and entertaining, even if the authenticity of images was uncertain. Pain and suffering were part of a spectacle that sustained the power of visual memory through the production of culture.

This chapter puts forth and defends three related claims about visual experience. First, it is argued that visual experiences have nonconceptual contents. Second, an explanation and defence is offered for the view that visual experience is representationally rich. This defence includes a discussion of several psychological experiments relating to sensory memory and change blindness. Finally, there is a discussion of how the thesis of richness relates to the thesis of fineness of grain, held most often in connection with our experiences of shades of colour. This discussion spells out the connection between the previously defended claims and the thesis that visual experiences have nonconceptual contents. In conclusion, the example of shape in visual experience is taken up as a potential problem for the thesis about nonconceptual content.

This chapter argues that the “divide and conquer” approach for understanding how the mind works (advocated by the traditional modular information-processing framework) has already provided about as much scientific advancement as it can. Further progress in the cognitive sciences is likely to require a more integrative dynamical and ecological approach to cognition that acknowledges not only the continuous and recurrent flow of information between different neural subsystems, but also the continuous and recurrent flow of information between the organism and the environment. Findings in change blindness, external memory use, and eye movements during imagery and memory are marshaled to support a visualization of mental content as something that spreads out beyond the body, sometimes overlapping with the mental content of other minds. The mind and its inextricable causes naturally extend to environmental forces (e.g., sensory, social, cultural, evolutionary) that operate at multiple interdependent time scales.

This chapter discusses three types of memory that are relevant for understanding how scene representations are generated over the course of scene viewing. It focuses particularly on scene memory generated dynamically across eye movements, and highlights studies that record eye movements. It argues that the results of studies focusing on transsaccadic memory, active on-line scene memory, and long-term scene memory converge on the conclusion that relatively detailed visual scene representations are retained both over the short and long term, and that these representations are generated incidentally as a consequence of scene viewing.

Recent research into change-blindness, memory-free visual search, and related phenomena have led some researchers to suggest that virtually no visual information is retained from individual fixations. This chapter reviews a number of studies that have recorded eye movements and subsequent visual memory in both laboratory and field settings. It concludes that while visual memory is sometimes quite poor, it is by no means absent in most situations. In most applied settings, records of people's eye movements will prove highly predictive of later memory performance. Factors such as emotional stress and danger which have been found to systematically distort people's memory for situations generally do so because they also distort people's eye movements. Nonetheless there is clear evidence that long-term memories are formed for items that have never been fixated directly, and there is also evidence for important differences in memory amongst different items that have been fixated.

At any moment of time the scene around us is filled with multifeatured objects, which we see from particular angles, distances, and illuminations, and which may themselves move and change. We must recognize their identities in order to retrieve semantic information relevant to our behaviour. However, we also need to represent their current state in order to interact with them, and store an episodic memory of the particular events in which they play a role. The object file metaphor was developed to help capture this type-token distinction in the perceptual domain and collected data showing object-specific priming to support the idea. This was applied to feature binding, to visual working memory, to negative priming, and to long-term learning in visual search.

This chapter uses the vehicle of visuospatial representations to explore broader issues of the top down modulation of association cortex linked to activity in the prefrontal cortex (PFC). One general emerging view from brain imaging, neuropsychological studies, and from single cell recording is that the control and maintenance functions of working memory appear to be linked with PFC activity. This chapter offers both functional magnetic resonance imaging (fMRI) and event-related potential (ERP) data, demonstrating how the PFC might contribute to the inhibition of irrelevant visual information while focusing on and maintaining visual information that is relevant to the task in hand. Some of the recent work using transcranial magnetic stimulation (TMS) to induce temporary lesions offers a promising additional source of evidence for this form of top-down modulation of visual processing.

This chapter presents a theory that applies the computational principles of TVA to attentional effects at the single-cell level: a neural theory of visual attention (NTVA). The basic idea of NTVA is that the two selection mechanisms of TVA – pigeonholing and filtering – are directly reflected in the activity of individual neurons: pigeonholing changes the activity level of individual neurons that signal particular categorizations, whereas filtering changes the number of neurons that respond to particular objects. In combination these two mechanisms control the total activity level in each population of neurons that signals a particular categorization of an object. In competition with other cell populations in the visual system, which support other categorizations, each population's level of activity determines whether the categorization it supports will enter visual short-term memory (VSTM).

This chapter expands the concepts of dynamic field theory (DFT) to activation distributions over multidimensional spaces. Multidimensional fields can be used either to represent inherently multidimensional features or for bringing different feature dimensions together in a single, integrated representation. Such integrated representations are costly in terms of neural resources, but greatly increase the behavioral repertoire of dynamic field (DF) models by enabling interactions between different feature spaces. Such interactions are demonstrated here in a model of attentional selection in early visual representations, which combines separate one-dimensional and integrated multidimensional DFs. The DF architecture accounts for visual search and touches on the binding problem in visual cognition. The chapter concludes with expansions of the basic architecture that deal with the effects of visual working memory on attentional processing and an explanation of the origin of illusory conjunctions.

This chapter comments on Anne Treisman's 1992 paper Automaticity and preattentive processing, published in the American Journal of Psychology and written in collaboration with Alfred Vieira and Amy Hayes. Treisman, Vieira, and Hayes report the results of experiments that probed automatized performance and preattentive processing in the context of visual search. They discuss the automaticity of search for random line patterns, automatization and localization specificity in search for features and conjunctions, automatization of integral processing, and the link between automatization and awareness. Furthermore, they consider stimuli that initially require focused attention and serial processing and the effects of extended practice in a search task by comparing the end result of practice with the preattentive processing of simple features. This chapter examines how visual processing is shaped by perceptual learning and visual memory, with particular reference to time scales of learning in visual discrimination and search tasks and the general principles that explain how experience improves visual performance.

Anthropoid primates enhanced stereoscopic vision and combined it with adaptations for diurnal foraging, including a fovea and full-color vision. Along with these developments, the posterior parietal and temporal areas of early primates elaborated into the feature memory system. The parietal parts of this system specialized in representing the metrics of resources, such as their distances and quantities; the temporal parts specialized in representing the visual and acoustic signs of resources, especially at a distance. In addition to anthropoid innovations, the feature system incorporated sensory areas that had evolved in early mammals, such as the perirhinal and primary visual cortex, as well as posterior parietal and temporal areas that had emerged in early primates. The anthropoid feature system functions in conjunction with the navigation system as neural substrates for the perceptions and memories that guide distance foraging.