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Can a blind person see? The very idea seems paradoxical. And yet, if we conceive of “seeing” as the ability to generate internal mental representations that may contain visual details, the idea of blind vision becomes a concept worth investigating. This book examines the effects of blindness and other types of visual deficits on the development and functioning of the human cognitive system. Drawing on behavioral and neurophysiological data, it analyzes research on mental imagery, spatial cognition, and compensatory mechanisms at the sensorial, cognitive, and cortical levels in individuals with complete or profound visual impairment. The authors find that the brain does not need eyes to “see.” They address critical questions of broad importance: The relationship of visual perception to imagery and working memory and the extent to which mental imagery depends on normal vision; the functional and neural relationships between vision and the other senses; the specific aspects of the visual experience which are crucial to cognitive development or specific cognitive mechanisms; and the extraordinary plasticity of the brain—as illustrated by the way that, in the blind, the visual cortex may be reorganized to support other perceptual or cognitive functions. In the absence of vision, the other senses work as functional substitutes and are often improved—pointing to the importance of the other senses in cognition.

Although William James declared in 1890, “Everyone knows what attention is,” today, there are many different and sometimes opposing views on the subject. This fragmented theoretical landscape may exist because most of the theories and models of attention offer explanations in natural language or in a pictorial manner rather than providing a quantitative and unambiguous statement of the theory, and focus on the manifestations of attention instead of its rationale. This book develops a formal model of visual attention with the goal of providing a theoretical explanation for why humans (and animals) must have the capacity to attend, and uses the full breadth of the language of computation—rather than simply the language of mathematics—as the formal means of description. The result, the Selective Tuning model of vision and attention, explains attentive behavior in humans and provides a foundation for building computer systems that see with human-like characteristics. The overarching conclusion is that human vision is based on a general purpose processor which can be dynamically tuned to the task and the scene viewed on a moment-by-moment basis. The book offers an overview of attention theories and models, and a description of the Selective Tuning model, confining the formal elements to two chapters and two appendixes. The text is accompanied by more than 100 illustrations in black and white and color; additional color illustrations and movies are available on the book’s website.

The recognition of faces is a fundamental visual function that is important for social interaction and communication. Scientific interest in facial recognition has increased dramatically over the last decade. Researchers in such fields as psychology, neurophysiology, and functional imaging have published more than 10,000 studies on face processing. Almost all of these studies focus on the processing of static pictures of faces; however, little attention has been paid to the recognition of dynamic faces, faces as they change over time—a topic in neuroscience that is also relevant to a variety of technical applications, including robotics, animation, and human–computer interfaces. This book offers an interdisciplinary overview of recent work on dynamic faces from the biological and computational perspectives. The chapters cover a range of topics, including the psychophysics of dynamic face perception, results from electrophysiology and imaging, clinical deficits in patients with impairments of dynamic face processing, and computational models that provide insights about the brain mechanisms for the processing of dynamic faces. The book offers neuroscientists and biologists a reference for designing experiments and provides computer scientists with knowledge that will help them improve technical systems for the recognition, processing, synthesizing, and animating of dynamic faces.

This posthumously published book (1982), which influenced a generation of brain and cognitive scientists, inspiring many to enter the field, describes a general framework for understanding visual perception and touches on broader questions about how the brain and its functions can be studied and understood. This MIT Press edition makes this work available to a new generation of students and scientists. In the author’s framework, the process of vision constructs a set of representations, starting from a description of the input image and culminating with a description of three-dimensional objects in the surrounding environment. A central theme, and one that has had far-reaching influence in both neuroscience and cognitive science, is the notion of different levels of analysis—in the author’s framework, the computational level, the algorithmic level, and the hardware implementation level. Now, thirty years later, the main problems that occupied the author remain fundamental open problems in the study of perception. His book provides inspiration for the continuing efforts to integrate knowledge from cognition and computation to understand vision and the brain.

Vision is one of the most active areas in biomedical research, and visual psychophysical techniques are a foundational methodology for this research enterprise. Visual psychophysics, which studies the relationship between the physical world and human behavior, is a classical field of study that has widespread applications in modern vision science. Bridging the gap between theory and practice, this textbook provides a comprehensive treatment of visual psychophysics, teaching not only basic techniques but also sophisticated data analysis methodologies and theoretical approaches. It begins with practical information about setting up a vision lab and goes on to discuss the creation, manipulation, and display of visual images; timing and integration of displays with measurements of brain activities and other relevant techniques; experimental designs; estimation of behavioral functions; and examples of psychophysics in applied and clinical settings. The book’s treatment of experimental designs presents the most commonly used psychophysical paradigms, theory-driven psychophysical experiments, and the analysis of these procedures in a signal-detection theory framework. The book discusses the theoretical underpinnings of data analysis and scientific interpretation, presenting data analysis techniques that include model fitting, model comparison, and a general framework for optimized adaptive testing methods. It includes many sample programs in Matlab with functions from Psychtoolbox, a free toolbox for real-time experimental control. Once students and researchers have mastered the material in this book, they will have the skills to apply visual psychophysics to cutting-edge vision science.