Special Issues of Visual Cognition – serie

A central goal in the study of object and scene perception is to understand how visual information is integrated across views to provide a stable, continuous experience of our environment. Research on issues ranging from visual masking to priming across saccades to the representation of spatial layout across views has addressed the issue of what information is preserved from one view to the next.Recently, research on visual memory for objects and scenes has led to striking claims about the nature of the information that is and is not preserved from one instant to the next. For example, studies of change blindness have shown that striking changes to objects and scenes can go undetected when they coincide with an eye movement, a flashed blank screen, a blink, or an occlusion event. These studies suggest that relatively little visual information about objects and scenes is combined across views. Despite these failures of change detection, observers somehow manage to experience a stable, continuous visual environment. This special issue seeks to unite recent studies of change blindness with studies of visual integration to better understand the nature of our representations and the richness of our visual memory.

In order to produce coherent behaviour in a complex world, forms of visual attention are necessary in order for us to select appropriate objects for action. Over the past ten years, there have been considerable advances in research into visual attention, with many of these advances linked to interdisciplinary research in experimental psychology, neuropsychology, neurophysiology and functional imaging. This work has begun to allow us to understand not only the functional properties of visual attention, but also how attentional processes are localized in the brain: the cognitive neuroscience of visual attention. This special issue draws together research from leading figures in this field, to highlight recent progress in understanding how selective processes operate in perception and action.

What we see and understand about the visual world is tightly tied to where we direct our eyes. High-resolution visual information is acquired from only a very limited region of the scene surrounding the fixation point, with the quality of visual input falling off precipitously from central vision into a low-resolution visual surround. This special issue of Visual Cognition brings together cutting-edge research from eight research groups around the world whose work is focused on these important topics. The goal of this special issue is to facilitate a constructive convergence of behavioral data and computational modeling to explore the fundamental nature of attention control, and particularly eye movement control, in viewing complex visual input.

The current volume, a special issue of Visual Cognition, brings together an eclectic group of investigators, all of whom study critical issues in the perception of true real-world scenes. Topics include the rapid acquisition of scene gist; scene recognition; spatial layout and spatial scale; distance perception in scenes; updating of scene views over time; visual search for meaningful objects in scenes; scene context effects on object perception; scene representation in memory; the allocation of attention including eye fixations during scene viewing; and the neural implementation of these representations and processes in the brain. Because the study of real-world scene perception benefits from an interdisciplinary approach, contributors to the volume use a variety of research methods including psychophysical and behavioral techniques, eyetracking, functional neuroimaging (including fMRI and ERP), and mathematical and computational modeling. While much has been learned from studying simplified visual stimuli, many of the articles in this volume make the important point that understanding the functional and neural architectures of the visual system requires studying how that system operates when faced with the types of real-world stimuli that evolution crafted it to handle.

A central goal in the study of object and scene perception is to understand how visual information is integrated across views to provide a stable, continuous experience of our environment. Research on issues ranging from visual masking to priming across saccades to the representation of spatial layout across views has addressed the issue of what information is preserved from one view to the next.Recently, research on visual memory for objects and scenes has led to striking claims about the nature of the information that is and is not preserved from one instant to the next. For example, studies of change blindness have shown that striking changes to objects and scenes can go undetected when they coincide with an eye movement, a flashed blank screen, a blink, or an occlusion event. These studies suggest that relatively little visual information about objects and scenes is combined across views. Despite these failures of change detection, observers somehow manage to experience a stable, continuous visual environment. This special issue seeks to unite recent studies of change blindness with studies of visual integration to better understand the nature of our representations and the richness of our visual memory.

In order to produce coherent behaviour in a complex world, forms of visual attention are necessary in order for us to select appropriate objects for action. Over the past ten years, there have been considerable advances in research into visual attention, with many of these advances linked to interdisciplinary research in experimental psychology, neuropsychology, neurophysiology and functional imaging. This work has begun to allow us to understand not only the functional properties of visual attention, but also how attentional processes are localized in the brain: the cognitive neuroscience of visual attention. This special issue draws together research from leading figures in this field, to highlight recent progress in understanding how selective processes operate in perception and action.

This special issue of Visual Cognition collects some 30 articles on Visual Search and Attention by leading experts from a variety of disciplines, including experimental psychology, neuropsychology, neurophysiology and computational modelling. The articles are updated versions of papers presented at the 2003 Munich Visual Search Symposium. The symposium’s goal, carried forward in this collection, was to foster an interdisciplinary dialogue, in order to identify important shared issues and consider ways of how these can be resolved using convergent methodologies. Reflecting the symposium discussions, the Special Issue is divided into four thematic sections: preattentive processing and role of memory in visual search, brain mechanisms and computational modelling of visual search.

The notion that certain mental or physical events can capture attention has been one of the most enduring topics in the study of attention owing to the importance of understanding how goal-directed and stimulus-driven processes interact in perception and cognition. Despite the clear theoretical and applied importance of attentional capture, a broad survey of this field suggests that the term "capture" means different things to different people. In some cases, it refers to covert shifts of spatial attention, in others involuntary saccades, and in still others general disruption of processing by irrelevant stimuli. The properties that elicit "capture" can also range from abruptly onset or moving lights, to discontinuities in textures, to unexpected tones, to emotionally valenced words or pictures, to directional signs and symbols. Attentional capture has been explored in both the spatial and temporal domains as well as the visual and auditory modalities. There are also a number of different theoretical perspectives on the mechanisms underlying "capture" (both functional and neurophysiological) and the level of cognitive control over capture. This special issue provides a sampling of the diversity of approaches, domains, and theoretical perspectives that currently exist in the study of attentional capture. Together, these contributions should help evaluate the degree to which attentional capture represents a unitary construct that reflects fundamental theoretical principles and mechanisms of the mind.

The remarkable complexity and sophistication of our perceptual systems have evolved for ultimately one purpose - to promote efficient and effective action within a constantly changing environment. Traditionally, the route from perception to action has often been viewed as a single, one-directional sequence of stages, which begins with a stimulus presentation and ends with a response. This view has tended to emphasize the separation of perception from action, with the result that studies of stimulus and response processing have often been carried out in isolation from each other. The work in this issue takes a different approach, which reflects renewed and increasing interest in how cognitive systems for vision and action are integrated. The studies here explore multiple pathways between vision and action, the ways in which vision promotes action, and even the conditions and degree to which action and its consequences can influence vision. A variety of methods and theoretical approaches are represented, in studies examining spatial coding, object processing, motor behaviour, attentional bias, and codes for action.

Vision is not an end in itself. Instead, it has evolved to assure survival in a dynamic environment. Vision - as well as the other senses - evolved from the necessity to act in this environment. Therefore, perceptual processes and action planning are much more interlocked than evident at first sight. This special issue examines the basic processes of space perception and how these processes interact with action planning and motor control. The tasks under consideration range from the simple localization of a single object to the coordination of a series of events in natural scenes. The contributions were written by various experts in the field, ranging from experimental psychologists, neurophysiologists to computational modellers and philosophers. Each contribution introduces new concepts and ideas that explain how visual space is being established and represented. The overarching question is whether vision and action are based on a single spatial map or on different, interacting spatial representations.

Some of the central problems to be solved by the brain, such as figure-ground coding and object recognition, concern the binding of separately coded feature elements into coherent object representations. The binding problem has recently been approached by a variety of disciplines, notably psychophysics, and experimental psychology, electrophysiology, neurophysiology and computational modelling. This special issue brings together a collection of papers principally from psychology and computational modelling. These papers address issues in Gestalt formation, the relation of grouping and binding processes to visual attention, the role of temporal factors for grouping and binding, the neuronal correlates of binding mechanisms, the development of binding operations in infants and the breakdown of these processes following brain injury.

It is widely recognized that visual processes modulate many social interactions. For example, the eye-gaze of another person is a powerful cue to guide attention to a particular part of the visual field. Conversely, a direct gaze may indicate potential threat or the opportunity for a sexual encounter. In addition, the social or affective significance of a stimulus, as well as the mood state of the observer, can have profound effects on basic attentional and perceptual processes. This special issue is aimed at elucidating the role of visual processes in social interactions by linking work on the basic cognitive mechanisms mediating vision with work on the social and emotional context in which the processing takes place.

Successfully completing many forms of behaviour requires that humans look in the right place at the right time: This has generated a large volume of research aimed at understanding how the eyes are guided. This special issue demonstrates that the decision about where to look involves a large number of factors from low- to high-level constraints. New models of eye guidance are presented, and these offer converging approaches to understanding how we inspect complex scenes. Importantly, this special issue brings together evidence from a range of settings - from static scene viewing to real world environments - in order to fully assess our current understanding of eye guidance in natural scenes.

Models of word and object processing have been informed by experimental data relating to the effects of important marker variables, particularly word frequency. In recent times, however, the role of word frequency has come to be questioned due to the demonstration of the impact of a correlated variable called "age of acquisition" (AoA), which is an index of when a word was first learned. Early acquired words tend to be of high frequency while late-acquired words tend to be of low frequency. Currently, there is a lively debate in the literature about the operation of AoA and word frequency in word and object processing, and how these effects might be modelled in connectionist architectures. Issues relate to: the relationship between AoA and word frequency; the locus of impact of AoA; and the types of identification task (e.g., recognition, comprehension or naming) that are influenced by the AoA of the target. Originally, AoA was thought to be a factor which operated at a name retrieval stage and which consequently only affected naming responses. However, more recent conceptualizations suggest that AoA effects arise out of the order in which items are learned and consequently may operate on many types of recognition task. Recent demonstrations of AoA effects in non-naming tasks may be seen to favour the latter explanation, but the debate is far from over.

The notion that certain mental or physical events can capture attention has been one of the most enduring topics in the study of attention owing to the importance of understanding how goal-directed and stimulus-driven processes interact in perception and cognition. Despite the clear theoretical and applied importance of attentional capture, a broad survey of this field suggests that the term "capture" means different things to different people. In some cases, it refers to covert shifts of spatial attention, in others involuntary saccades, and in still others general disruption of processing by irrelevant stimuli. The properties that elicit "capture" can also range from abruptly onset or moving lights, to discontinuities in textures, to unexpected tones, to emotionally valenced words or pictures, to directional signs and symbols. Attentional capture has been explored in both the spatial and temporal domains as well as the visual and auditory modalities. There are also a number of different theoretical perspectives on the mechanisms underlying "capture" (both functional and neurophysiological) and the level of cognitive control over capture. This special issue provides a sampling of the diversity of approaches, domains, and theoretical perspectives that currently exist in the study of attentional capture. Together, these contributions should help evaluate the degree to which attentional capture represents a unitary construct that reflects fundamental theoretical principles and mechanisms of the mind.

Visual processing acts as a prism, splitting visual information from the retinal image into separately processed features such as color, shape, and orientation. Binding refers to the set of cognitive and neural mechanisms that re-integrate these features to create a holistic representation of the objects in the visual field. The binding problem in vision refers to how this integration is achieved. The binding problem, however, isn’t a singular problem, but a constellation of interrelated problems. The articles in this special issue of Visual Cognition cover three major types of binding, each of which may require a unique solution: The binding of features within objects, the relational binding among objects, and the binding between temporally related events. Within these broad topics, articles consider the role of attention in feature binding, the representation of static and moving multi-feature objects, the binding of objects to scenes, binding processes involved in learning and long-term memory, the development of binding abilities, and binding of information between visual and non-visual memory systems. Rather than disseminate conclusive solutions to these various instantiations of the binding problem, this collection of work describes the current state-of-the science, highlights the interconnections between the binding problems and the approaches taken to solve them, and outlines the critical issues that have yet to be resolved. In this single volume readers will confront work with children, young adults, and patients, and work that uses traditional behavioural measures, eye movement recording, functional imaging, and transcranial magnetic stimulation.

Some of the central problems to be solved by the brain, such as figure-ground coding and object recognition, concern the binding of separately coded feature elements into coherent object representations. The binding problem has recently been approached by a variety of disciplines, notably psychophysics, and experimental psychology, electrophysiology, neurophysiology and computational modelling. This special issue brings together a collection of papers principally from psychology and computational modelling. These papers address issues in Gestalt formation, the relation of grouping and binding processes to visual attention, the role of temporal factors for grouping and binding, the neuronal correlates of binding mechanisms, the development of binding operations in infants and the breakdown of these processes following brain injury.

The remarkable complexity and sophistication of our perceptual systems have evolved for ultimately one purpose - to promote efficient and effective action within a constantly changing environment. Traditionally, the route from perception to action has often been viewed as a single, one-directional sequence of stages, which begins with a stimulus presentation and ends with a response. This view has tended to emphasize the separation of perception from action, with the result that studies of stimulus and response processing have often been carried out in isolation from each other. The work in this issue takes a different approach, which reflects renewed and increasing interest in how cognitive systems for vision and action are integrated. The studies here explore multiple pathways between vision and action, the ways in which vision promotes action, and even the conditions and degree to which action and its consequences can influence vision. A variety of methods and theoretical approaches are represented, in studies examining spatial coding, object processing, motor behaviour, attentional bias, and codes for action.

Vision is not an end in itself. Instead, it has evolved to assure survival in a dynamic environment. Vision - as well as the other senses - evolved from the necessity to act in this environment. Therefore, perceptual processes and action planning are much more interlocked than evident at first sight. This special issue examines the basic processes of space perception and how these processes interact with action planning and motor control. The tasks under consideration range from the simple localization of a single object to the coordination of a series of events in natural scenes. The contributions were written by various experts in the field, ranging from experimental psychologists, neurophysiologists to computational modellers and philosophers. Each contribution introduces new concepts and ideas that explain how visual space is being established and represented. The overarching question is whether vision and action are based on a single spatial map or on different, interacting spatial representations.

It is widely recognized that visual processes modulate many social interactions. For example, the eye-gaze of another person is a powerful cue to guide attention to a particular part of the visual field. Conversely, a direct gaze may indicate potential threat or the opportunity for a sexual encounter. In addition, the social or affective significance of a stimulus, as well as the mood state of the observer, can have profound effects on basic attentional and perceptual processes. This special issue is aimed at elucidating the role of visual processes in social interactions by linking work on the basic cognitive mechanisms mediating vision with work on the social and emotional context in which the processing takes place.

The current volume, a special issue of Visual Cognition, brings together an eclectic group of investigators, all of whom study critical issues in the perception of true real-world scenes. Topics include the rapid acquisition of scene gist; scene recognition; spatial layout and spatial scale; distance perception in scenes; updating of scene views over time; visual search for meaningful objects in scenes; scene context effects on object perception; scene representation in memory; the allocation of attention including eye fixations during scene viewing; and the neural implementation of these representations and processes in the brain. Because the study of real-world scene perception benefits from an interdisciplinary approach, contributors to the volume use a variety of research methods including psychophysical and behavioral techniques, eyetracking, functional neuroimaging (including fMRI and ERP), and mathematical and computational modeling. While much has been learned from studying simplified visual stimuli, many of the articles in this volume make the important point that understanding the functional and neural architectures of the visual system requires studying how that system operates when faced with the types of real-world stimuli that evolution crafted it to handle.

Successfully completing many forms of behaviour requires that humans look in the right place at the right time: This has generated a large volume of research aimed at understanding how the eyes are guided. This special issue demonstrates that the decision about where to look involves a large number of factors from low- to high-level constraints. New models of eye guidance are presented, and these offer converging approaches to understanding how we inspect complex scenes. Importantly, this special issue brings together evidence from a range of settings - from static scene viewing to real world environments - in order to fully assess our current understanding of eye guidance in natural scenes.