Ferdinand Pöhlmann argues that a sense of one’s own basic abilities to move is a constitutive condition on the ability to perceive the world spatially. This constitutive relation explains why egocentric spatial representation is to be regarded as a kind of self-representation. In arguing for these claims, conceptual as well as empirical questions are discussed and an overview of accounts that take action as a constitutive condition on spatial representation is given. The picture that emerges is linked to the phenomenological (...) (Scheler) as well as to the analytic (Evans) tradition in the Philosophy of Mind.​. (shrink)

This paper proposes a novel experimental approach that would help to determine whether perspectival shapes, such as the elliptical profile of a tilted plate or coin, are part of perceptual experience. If they are part of perceptual experience, then it should be possible to identify these shapes simply by attending appropriately to them. Otherwise, in order to identify perspectival shapes they must first be constructed in the visual imagination. We propose that these accounts of perspectival identification can be tested by (...) measuring the interference between visual and verbal working memory load, respectively, and the identification of perspectival shapes in the appearance of a 3D object. (shrink)

The cerebral cortex is a rich and diverse structure that is the basis of intelligent behavior. One of the deepest mysteries of the function of cortex is that neural processing times are only about one hundred times as fast as the fastest response times for complex behavior. At the very least, this would seem to indicate that the cortex does massive amounts of parallel computation.This paper explores the hypothesis that an important part of the cortex can be modeled as a (...) connectionist computer that is especially suited for parallel problem solving. The connectionist computer uses a special representation, termed value unit encoding, that represents small subsets of parameters in a way that allows parallel access to many different parameter values. This computer can be thought of as computing hierarchies of sensorimotor invariants. The neural substrate can be interpreted as a commitment to data structures and algorithms that compute invariants fast enough to explain the behavioral response times. A detailed consideration of this model has several implications for the underlying anatomy and physiology. (shrink)

The cerebral cortex is a rich and diverse structure that is the basis of intelligent behavior. One of the deepest mysteries of the function of cortex is that neural processing times are only about one hundred times as fast as the fastest response times for complex behavior. At the very least, this would seem to indicate that the cortex does massive amounts of parallel computation.This paper explores the hypothesis that an important part of the cortex can be modeled as a (...) connectionist computer that is especially suited for parallel problem solving. The connectionist computer uses a special representation, termed value unit encoding, that represents small subsets of parameters in a way that allows parallel access to many different parameter values. This computer can be thought of as computing hierarchies of sensorimotor invariants. The neural substrate can be interpreted as a commitment to data structures and algorithms that compute invariants fast enough to explain the behavioral response times. A detailed consideration of this model has several implications for the underlying anatomy and physiology. (shrink)

Warren's major contention is that judgments of subjective magnitude are not possible, and therefore subjects base such judgments upon physical correlates of the dimension in question. It would appear that Warren's theory will almost surely fail as a comprehensive model, even though it does provide a heuristic account of judgments of loudness and brightness. In order for the theory to succeed, Warren must specify a physical correlate for judgments ofeverysubjective attribute that has yielded orderly data with Stevens's scaling procedures.

The measurement of sensory intensity has had a long history, attracting the attention of investigators from many disciplines including physiology, psychology, physics, mathematics, philosophy, and even chemistry. While there has been a continuing doubt by some that sensation has the properties necessary for measurement, experiments designed to obtain estimates of sensory intensity have found that a general rule applies: Equal stimulus ratios produce equal sensory ratios. Theories concerning the basis for this simple psychophysical rule are discussed, with emphasis given to (...) the physical correlate theory, which considers judgments of subjective magnitudes to be based upon estimates of physical dimensions that vary regularly with changes in degree of stimulation. For the most thoroughly investigated sensory scales, brightness and loudness, the physical correlate is considered to be distance. Our “tacit knowledge” of the sensory effects of changing distance plays an essential role in matching motor activities to environmental conditions and in ensuring accurate perceptual evaluations through brightness and loudness constancies. In psychophysical experiments, subjects apparently use this same tacit knowledge when required to estimate relative subjective magnitudes. The evidence related to the physical correlate theory is summarized, and it is concluded that, while under appropriate conditions we demonstrate considerable skill in evaluating environmental relationships, we are quite unable to estimate the neurophysiological nature or quantity of sensory response. A psychophysics devoted to studying conditions required for accuracy and conditions producing errors in the perception of environmental relationships would seem to be more valuable than one devoted to subjective magnitudes. (shrink)

After writing my response to the commentaries, I sat back and reflected on the fascination and frustration of work on this topic. There is the ancient fascination of trying to understand the nature of the sensory bridge linking us to the external world. Also, discussing the measurability of sensation brings to the surface concepts we use and take for granted when we are working in other areas of psychology; and it holds them before us for critical examination. The frustration lies (...) chiefly in the difficulty of formulating concepts clearly, in a way understood by all. At least when constructing the original Tower of Babel, workers hearing strange words knew that communication was not occurring. The psychophysical Tower of Babel sometimes has workers using the same words, but with different meanings. Much of my response is based on attempts to clarify concepts and clear up confusions. (shrink)

Theorizing about perception is often motivated by a belief that without a way of ensuring that our perceptual experience correctly reflects the external world we cannot be sure that we perceive the world at all. Historically, coming up with a way of securing such epistemic contact has been a foundational issue in psychology. Recent ecological and enactive approaches challenge the requirement for perception to attain epistemic contact. This article aims to explicate this pragmatic starting point and the new direction of (...) inquiry that this opens up for psychology. It does so by detailing the development of James J. Gibson’s ecological psychology. Securing epistemic contact has been a leitmotiv in Gibson’s early work, but subsequent developments in Gibson’s works can teach us what it takes to adopt a pragmatic approach to psychology. We propose a reading of the developments in Gibson’s original works that shows that, since perception is a mode of acting, perception aims for pragmatic contact before allowing for epistemic contact. Amplifying these pragmatist lines of thought in Gibson’s works we end by considering situations where an individual is adapted to the intricacies of specific social practices. These situations show how pragmatic contact can also afford attaining epistemic contact. (shrink)

Central to contemporary cognitive science is the notion that mental processes involve computations defined over internal representations. This view stands in sharp contrast to the to visual perception and cognition, whose most prominent proponent has been J.J. Gibson. In the direct theory, perception does not involve computations of any sort; it is the result of the direct pickup of available information. The publication of Gibson's recent book (Gibson 1979) offers an opportunity to examine his approach, and, more generally, to contrast (...) the theory of direct perception with the computational/representational view. In the first part of the present article (Sections 2direct perceptioncase study”: the problem of perceiving the three-dimensional shape of moving objects is examined. This problem, which has been extensively studied within the immediate perception framework, serves to illustrate some of the inherent shortcomings of that approach. Finally, in Section 5, an attempt is made to place the theory of direct perception in perspective by embedding it in a more comprehensive framework. (shrink)