Tachistoscopic exposure of real objects for measurement of reaction time and movement time

In this paper, we describe an apparatus for measuring reaction times and movement times involved in reaching for real objects. Subjects view an object through a liquid crystal window, which serves as a shutter that can be made clear or opaque quickly (10 msec from opaque to clear, 30 msec from clear to opaque). The subject’s hand rests on a microswitch-equipped home key, and the object sits on a force-sensitive platform so that initiation of reach and time of contact with the object can be marked accurately. The apparatus interfaces with an IBM PC/AT through a digital I/O parallel port, so that reaction times and movement times are recorded automatically.     

Haptic classification of common objects: Knowledge-driven exploration

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 of the natural co-occurrence of properties in haptic object perception. In Experiment 2, the hand movements executed during haptic classification of manipulable common objects were examined. Manual exploration consisted of a two-stage sequence, an initial generalized "grasp-and -lift" routine, followed by a series of more specialized hand-movement patterns strongly driven by knowledge of the property diagnosticity for the specific object (obtained in Experiment 1). The current results may guide computational models of human haptic object classification and the development of perceptual systems for robots equipped with sensate dextrous hands, capable of intelligent exploration, recognition, and manipulation of concrete objects.