Cognitive Salience of Haptic Object Properties: Role of Modality-Encoding Bias

Abstract

The influence of modality-encoding bias on the relative importance ('cognitive salience') of object shape, size, and material, with the last determined by weight and thermal variations, was examined. Experiment 1 confirmed that for these stimulus objects all five properties were very accessible haptically, as measured by the time to identify the property level of each designated property; however, observers were still generally faster for geometric than material properties. In experiment 2, the influence of modality-encoding bias on cognitive salience was assessed by using a task involving free sorting by similarity. As predicted, modality-encoding bias strongly influenced cognitive salience. Observers favoured sorting by material under haptic- bias instructions, and three-dimensional geometric properties (especially shape) under visual-bias instructions. Videotaped hand movements indicated that modality-encoding biases reflect long-term knowledge of the relative speed and precision of manual exploration patterns, rather than exploration of the current set of objects.

Haptic perception: A tutorial

“…When the properties of objects are matched for perceptual discriminability, observers judging interobject similarity attend to material properties (texture, compliance, thermal, and weight) more when objects are encoded by touch alone than when objects are seen while being touched. Conversely, they weight geometric properties (2-D and 3-D shape and size) more when examining the same objects with vision present than by touch alone (e.g., Klatzky, Lederman, & Reed, 1987;Lederman, Summers, & Klatzky, 1996). The greater salience of material properties under haptic exploration presumably reflects the findings that a greater number of EPs convey information about material than geometry, and that EPs optimized for encoding material (cf.…”

The effects of size changes on haptic object recognition

“…They found that although haptics and vision use broadly similar perceptual maps for comparing stimuli, shape was much more important than texture for vision, whereas shape and texture were similarly important for haptics. In a free-sorting task, Lederman, Summers, and Klatzky (1996) found that shape was the most salient dimension for both touch and vision, and that shape was more salient for vision than for touch. Size was as rapidly available as shape for haptics, but it was not a salient dimension for either touch or vision.…”

Haptics and graphic analogies for the understanding of atomic force microscopy

“…For example, geometric tasks that require haptic recognition without vision are performed relatively poorly, whereas material properties are processed more precisely and quickly. Furthermore, there is dominance of vision over haptics on extracting geometric information because vision can extract spatial details far more precisely and faster than can any haptic exploration procedure (Lederman et al, 1996).…”

“…Haptic perception and representation are based on inputs from mechanoreceptors and thermoreceptor subsystems in the skin, as well as on position-sensing and force-sensing mechanisms that exist in muscles, tendons and joints (Lederman et al, 1996). By exploiting the haptic system, subjects are able to extract different kinds of information from the manual exploration of objects (Lederman and Klatzky, 1987) such as their material properties (e.g., surface texture, hardness, thermal, weight), their geometric properties (those pertaining to shape and size), their mechanical properties (e.g., motion of an object part), and their functional properties (as determined from object structure).…”