THE JAPANESE JOURNAL OF EDUCATIONAL RESEARCH
Online ISSN : 2187-5278
Print ISSN : 0387-3161
ISSN-L : 0387-3161
Beyond the Boundary of 'Optics' : An Ecological Approach to Cognition on the Part of Visually Handicapped
Masato Sasaki
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1997 Volume 64 Issue 3 Pages 317-326

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Abstract

By means of participatory observation and interviews with severely visually handicapped (totally blind) persons, a considerable amount of useful information was acquired in terms of their ability to navigate their way through their environment. For example, by means of an acoustic structured array consisting of radiated and reverberating sounds they can specify the cross-sections or 'places of transition' where an adjoining side-wall is no longer present. Also, blind navigators detect route continuity in the route they are following by means of detailed adjacent haptic array of ground. Their ability to navigate is based on detecting environmental structures as revealed over time along a habitually traveled route. These distinctive types of information specifying particular route properties are variable and ubiquitous, and are embedded in surrounding environment. Blind persons, and of course sighted, are supported by these environmental (ecological) resources in terms of route navigation. However, traditional studies of 'spatial cognition' on the part of the visually handicapped have neglected these rich ambient resources and focused only on 'internal or mental cognitive representation'. One type of optic theory, Cartesian optics, was responsible for establishing such a tradition. Since the Renaissance, Western thinkers have treated seeing as a matter of having images. Descartes used of perspective geometry to question whether optically formed images need even partially resemble their objects. He asserted that resemblance was unimportant and rejected the image theory of vision. For Descartes, it is small nerve 'movements' that cause seeing, not the image at the back of the eye. According to his doctrine, all seeing has to be explained as an interpretation by the 'mind' of subjective effects of these point stimulation. This theory promoted the one question about blind peoples' cognition, namely that concerned with relationship between physical sensory experience and meaningful perceptual experience. How does restricted sensory experience affect blind spatial cognition ? In this context, question about blind cognition appeared very narrow. J.J. Gibson (1904-1979), american psychologist distinguishes light as physical energy, light as a stimulus for vision, and light as information for perception. His 'ecological optics' is concerned with the information for perception that is available in the environment. Illumination as the result of reverberating between surfaces that face one other is a fact of higher order than radiation. In an illuminated environment, one could think of the rays as completely filling the air and think of each point in the air as a point of intersection of rays coming from all directions. Light which is ambient at every point is the result of illumination and has a structure dependent on the surfaces in the environment and can be information for perception. Structured ambient light, ambient optic array guide navigation. For example, a woman with a low level of vision uses this structured light (see Picture 1). Information in term of useful resources for navigation can be found in ambient light, sound and continual haptic adjacent order. With ecological optics as base, the study of cognition in blind persons is able to go beyond the boundaries of Cartesian optics and enable a pluralistic approach to this problem.

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