Visual and tactile scanning: Moving scan versus moving medium

Abstract

Two models of scanning are examined: a moving attention focus (and fixed spatial medium) versus a moving medium (and fixed focus of attention). These are referred to respectively as moving scan and moving medium models. Kosslyn (1980) has argued for a moving medium model in visual imagery. These models were tested by examining distance estimates of the separation of two points on a map as perceived through an aperture in visual and tactile modes. In the first experiment, viewing a map moving behind a stationary aperture (moving medium condition) led to significantly less accurate spatial distance judgments than did viewing the aperture moving over the map (moving scan condition). In the second experiment, vision and touch were compared. Distance estimates were larger for the moving scan condition than for the moving medium condition. Distance estimates were also larger for visual than for touch conditions. Moreover, modality did not interact with the manipulation of moving medium versus moving scan. It was concluded that (1) reception and representation of information through an aperture involves a general type of processing not specific to any one sensory modality, and (2) strongest support is found for the moving scan model in which an attention pointer moves across a fixed medium. © 1985, The psychonomic Society, Inc.. All rights reserved.