Gillian Rhodes - Böcker

From a barrage of photons, we readily and effortlessly recognize the faces of our friends, and the familiar objects and scenes around us. However, these tasks cannot be simple for our visual systems--faces are all extremely similar as visual patterns, and objects look quite different when viewed from different viewpoints. How do our visual systems solve these problems? The contributors to this volume seek to answer this question by exploring how analytic and holistic processes contribute to our perception of faces, objects, and scenes. The role of parts and wholes in perception has been studied for a century, beginning with the debate between Structuralists, who championed the role of elements, and Gestalt psychologists, who argued that the whole was different from the sum of its parts. This is the first volume to focus on the current state of the debate on parts versus wholes as it exists in the field of visual perception by bringing together the views of the leading researchers. Too frequently, researchers work in only one domain, so they are unaware of the ways in which holistic and analytic processing are defined in different areas. The contributors to this volume ask what analytic and holistic processes are like; whether they contribute differently to the perception of faces, objects, and scenes; whether different cognitive and neural mechanisms code holistic and analytic information; whether a single, universal system can be sufficient for visual-information processing, and whether our subjective experience of holistic perception might be nothing more than a compelling illusion. The result is a snapshot of the current thinking on how the processing of wholes and parts contributes to our remarkable ability to recognize faces, objects, and scenes, and an illustration of the diverse conceptions of analytic and holistic processing that currently coexist, and the variety of approaches that have been brought to bear on the issues.

Adaptation phenomena provide striking examples of perceptual plasticity and offer valuable insight into the mechanisms of visual coding. The technique of psychophysical adaptation has aptly been termed the psychologist's microelectrode because of its usefulness in investigating the coding of sensory information in the human brain. Its broader relevance though is illustrated by the increasing use of adaptation to study more cognitive aspects of vision such as the mechanisms of face perception and the neural substrates of visual awareness.This book brings together a collection of studies from international researchers, which demonstrate the brain's remarkable capacity to adapt its representation of the visual world in response to changes in its environment. A major theme throughout is that adaptation at all stages of visual processing serves a functional role in the efficient representation of the prevailing visual environment. Information about the visual world is coded in the rate at which neurons fire. However, neurons can only respond over a certain range of firing rates. Adaptation of the way in which neurons code visual information tends to make optimal use of this limited response range. Though these principles are well established at the level of light adaptation in the retina, it is only relatively recently that researchers have started to look for analogous behaviour at the higher levels of the visual system. This book is the first to bring together evidence that adaptation in high-level vision, as at the lower levels, serves to fit the mind to the world.

As Nixon's unpopularity increased during Watergate, his nose and jowls grew to impossible proportions in published caricatures. Yet the caricatures remained instantly recognizable. Caricatures can even be superportraits, with the paradoxical quality of being more like the face than the face itself.How can we recognize such distorted images? Do caricatures derive their power from some special property of a face recognition system or from some more general property of recognition systems? What kind of mental representations and recognition processes make caricatures so effective? What can the power of caricatures tell us about recognition?In seeking to answer these questions, the author assembles clues from a variety of sources: the invention and development of caricatures by artists, the exploitation of extreme signals in animal communication systems, and studies of how humans, other animals and connectionist recognition systems respond to caricatures.Several conclusions emerge. The power of caricatures is ubiquitous. Caricatures can be superportraits for humans, other animals and computer recognition systems. They are effective for a variety of stimuli, not just faces. They are effective whether objects are mentally represented as deviations from a norm or average member of the class, or as absolute feature values on a set of dimensions. Exaggeration of crucial norm-deviation features, distinctiveness, and resemblance to caricatured memory traces are all potential sources of the power of caricature.Superportraits will be of interest to students of cognitive psychology, perception, the visual arts and animal behavior.