The independence of size perception and distance perception

Research on distance perception has focused on environmental sources of information, which have been well documented; in contrast, size perception research has focused on familiarity or has relied on distance information. An analysis of these two parallel bodies of work reveals their lack of equivalence. Furthermore, definitions of familiarity need environmental grounding, specifically concerning the amount of size variation among different tokens of an object. To demonstrate the independence of size and distance perception, subjects in two experiments were asked to estimate the sizes of common objects from memory and then to estimate both the sizes and the distances of a subset of such objects displayed in front of them. The experiments found that token variation was a critical variable in the accuracy of size estimations, whether from memory or with vision, and that distance had no impact at all on size perception. Furthermore, when distance information was good, size had no effect on distance estimation; in contrast, at far distances, the distances to token variable or unknown objects were estimated with less accuracy. The results suggest that size perception has been misconceptualized, so that the relevant research to understand its properties has not been undertaken. The size-distance invariance hypothesis was shown to be inadequate for both areas of research.     

Pre-emptive perception

How can an action to a target be selected without yet knowing what it is? Pre-emptive perception (PEP) is a framework which orders neuronal mechanisms in association with voluntary actions before an action is started and until it is completed. It is assumed that PEP serves the purpose of perception, but a conscious, perceptual identification of the goal is not obligatorily completed during the time period of PEP itself. The concept of PEP is that the brain pre-emptively optimizes an action plan to maximize eventual perception, even before being sure what the goal is. Experimental studies of voluntary saccadic eye movements are considered as prototypic activity within the framework of PEP. The core concept of pre-emption is that a particular saccade is selected while a large number of other possible actions are deselected. Pre-emptive computations include mechanisms associated with internal context and reward. Neurophysiological studies which show anatomically and functionally separate cortical and some subcortical neuronal groups in computing saccades are summarized. There is a potential relationship of PEP as a neurobiological framework and some philosophical concepts. Terms for processes between planning and action, such as intention, anticipation, and attention, are often incongruent in everyday language and in epistemology. It is proposed here that a scrutiny of these terms can be rigorously approached by temporal subdivision of PEP and conversely, clear definitions of these terms can lead to organized experimental designs of cognitive neurobiology. The temporal subdivision of PEP allows a critique of The Will in the definition of Schopenhauer and distinguishes it from the 'free will'.     

Pitch perception

This article is a review of the psychophysical study of pitch perception. The history of the study of pitch has seen a continual competition between spectral and temporal theories of pitch perception. The pitch of complex stimuli is likely based on the temporal regularities in a sound’s waveform, with the strongest pitches occurring for stimuli with low-frequency components. Thus, temporal models, especially those based on autocorrelationlike processes, appear to account for the majority of the data.     

The independence of size perception and distance perception.

Research on distance perception has focused on environmental sources of information, which have been well documented; in contrast, size perception research has focused on familiarity or has relied on distance information. An analysis of these two parallel bodies of work reveals their lack of equivalence. Furthermore, definitions of familiarity need environmental grounding, specifically concerning the amount of size variation among different tokens of an object. To demonstrate the independence of size and distance perception, subjects in two experiments were asked to estimate the sizes of common objects from memory and then to estimate both the sizes and the distances of a subset of such objects displayed in front of them. The experiments found that token variation was a critical variable in the accuracy of size estimations, whether from memory or with vision, and that distance had no impact at all on size perception. Furthermore, when distance information was good, size had no effect on distance estimation; in contrast, at far distances, the distances to token variable or unknown objects were estimated with less accuracy. The results suggest that size perception has been misconceptualized, so that the relevant research to understand its properties has not been undertaken. The size-distance invariance hypothesis was shown to be inadequate for both areas of research.     

Keeping perception accurate

Perception should change if an error in perception is detected. Yet how can information that comes through the senses ever indicate that those very senses aren't accurate? Knowledge of objects that arises independently of sensory experience can be used to check the sensory information for errors. For instance, an a priori constraint that one object cannot be in two places at the same time would lead to error detection if the sensory systems suggest that one object is in two places. Variants on the classic prism-adaptation phenomenon have revealed new rules about changes in space perception. These variants involve specifying new unusual mappings between visual space and motor (proprioceptive) space, and testing for generalization to novel untrained locations. The research has suggested that there is a preference for changes in space perception that shift space rigidly everywhere, that shrink or expand space uniformly, and that preserve the one-to-one relationship between modalities. Finally, this review discusses the issue that perception must change to remain accurate in the face of childhood growth and adult drift.     

Unity of perception

Perceptual scientists have recently enjoyed success in constructing mathematical theories for specific perceptual capacities, capacities such as stereovision, auditory localization, and color perception. Analysis of these theories suggests that they all share a common mathematical structure. If this is true, the elucidation of this structure, the study of its properties, the derivation of its consequences, and the empirical testing of its predictions are promising directions for perceptual research. We consider a candidate for the common structure, a candidate called an "observer". Observers, in essence, perform inferences; each observer has a characteristic class of perceptual premises, a characteristic class of perceptual conclusions, and its own functional relationship between these premises and conclusions. If observers indeed capture the structure common to perceptual capacities, then each capacity, regardless of its modality or manner of instantiation, can be described as some observer. In this paper we develop the definition of an observer. We first consider two examples of perceptual capacities: the measurement of visual motion, and the perception of depth from visual motion. In each case, we review a formal theory of the capacity and abstract its structural essence. From this essence we construct the definition of observer. We then exercise the definition in discussions of transduction, perceptual illusions, perceptual uncertainty, regularization theory, the cognitive penetrability of perception, and the theory neutrality of observation.     

Other-race face perception

The other-race effect (or own-race bias or cross-racial identification effect) refers to the finding that recognition memory tends to be better for faces of members of subjects' own race than for faces of members of other races. The current study was designed to test the hypothesis that perceptual skills specific to identifying faces of particular racial groups contribute to this effect. On each of 50 trials, a photograph of a face was tachistoscopically presented for 120 ms, followed by a pattern mask and then a plain-view test pair composed of the previously presented face and a matched foil. As predicted, an other-race effect was obtained on this perceptual task: White subjects performed significantly more poorly on trials involving African American faces than on trials involving White faces, whereas no such difference was obtained among African American subjects.     

Intersubjectivity in perception

The embodied, embedded, enactive, and extended approaches to cognition explicate many important details for a phenomenology of perception, and are consistent with some of the traditional phenomenological analyses. Theorists working in these areas, however, often fail to provide an account of how intersubjectivity might relate to perception. This paper suggests some ways in which intersubjectivity is important for an adequate account of perception.