COGNITIVE SALIENCE OF HAPTIC OBJECT PROPERTIES - ROLE OF MODALITY-ENCODING BIAS

The influence of modality-encoding bias on the relative importance ('c ognitive 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 pr operty level of each designated property; however, observers were stil l generally faster for geometric than material properties. In experime nt 2, the influence of modality-encoding bias on cognitive salience wa s assessed by using a task involving free sorting by similarity. As pr edicted, modality-encoding bias strongly influenced cognitive salience . Observers favoured sorting by material under haptic-bias instruction s, and three-dimensional geometric properties (especially shape) under visual-bias instructions. Videotaped hand movements indicated that mo dality-encoding biases reflect longterm knowledge of the relative spee d and precision of manual exploration patterns, rather than exploratio n of the current set of objects.