Processing Haptic Features From an Initial Brief Contact

What types of haptic information should be delivered to the hand of a human operator when performing teleoperational tasks or exploring a virtual environment? This experimental study proposes early perceptual features that are available for haptic processing following brief manual contact, and therefore are candidates for real-time guidance of manual responses. The criterion for inclusion in the set of early perceptual features was evidence of parallel search across the fingers. A number of easy intensive discriminations involving material properties and abrupt surface discontinuities were processed in parallel across the entire display, regardless of display size. In striking contrast, most spatial-relations discriminations produced item-by-item search. The discussion also considers the relevance of the current results for designing haptic interfaces for teleoperation and virtual environments, and the functions served by early feature extraction from minimal contact. At the 1993 meeting of the Psychonomics Society, we described some initial studies from our research program on haptic search. These studies used a paradigm developed by Anne Treisman, in which subjects search for a target stimulus among a set of nontarget (i.e., distractor) items. The target differs from the distractors by virtue of its value on some dimension. For example, the target may be very rough and the distractors very smooth. Response time is considered as a function of the number of items in the search display. When this function is flat, the target is said to “pop out.”