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Two experiments establish links between desired knowledge about objects and hand movements during haptic object exploration. Experiment 1 used a match-to-sample task, in which blindfolded subjects were directed to match objects on a particular dimension (e.g., texture). Hand movements during object exploration were reliably classified as " exploratory(More)
Blindfolded sighted, adventitiously blind, and congenitally blind subjects performed a set of navigation tasks. The more complex tasks involved spatial inference and included retracing a multisegment route in reverse, returning directly to an origin after being led over linear segments, and pointing to targets after locomotion. As a group, subjects(More)
293 Abstract— Two studies investigated updating of self-position and heading during real, imagined, and simulated locomotion. Subjects were exposed to a two-segment path with a turn between segments; they responded by turning to face the origin as they would if they had walked the path and were at the end of the second segment. The conditions of pathway(More)
Although the literatures on human spatial cognition and animal navigation often make distinctions between egocentric and allocentric (also called exocentric or geocentric) representations, the terms have not generally been well defined. This chapter begins by making formal distinctions between three kinds of representations: allocentric locational,(More)
Three experiments investigated auditory distance perception under natural listening conditions in a large open field. Targets varied in egocentric distance from 3 to 16 m. By presenting visual targets at these same locations on other trials, we were able to compare visual and auditory distance perception under similar circumstances. In some experimental(More)
Vibratory roughness perception occurs when people feel a surface with a rigid probe. Accordingly, perceived roughness should reflect probe and surface geometry, exploratory speed, and force. Experiments 1 and 2 compared magnitude estimation of roughness with the bare finger and two types of probes, one designed to eliminate force moments, under the(More)
Subjects made roughness judgments of textured surfaces made of raised elements, while holding stick-like probes or through a rigid sheath mounted on the fingertip. These rigid links, which impose vibratory coding of roughness, were compared with the finger (bare or covered with a compliant glove), using magnitude-estimation and roughness differentiation(More)
In Experiment 1, haptically available object properties that would be diagnostic for constrained common object classification at the basic and subordinate levels were elicited in a questionnaire. The results are considered in terms of the nature of the haptically derived representations of common objects. Initial data are also presented regarding knowledge(More)
This paper describes preliminary work in the use of a virtual environment to derive just noticeable differences (JNDs) for force. Specifically, we look for thresholds of force sensitivity so that we may ultimately construct therapeutic force feedback distortions that stay below these thresholds. Initially, we have concentrated on JNDs as they are applied to(More)
SUMMARY The availability and salience of object attributes under haptic exploration, with and without vision, were assessed by two tasks in which subjects sorted objects that varied factorially in size, shape, texture, and hardness. In the directed-discrimination task, sub-jeets were instructed to sort along a particular dimension. Although levels on all(More)