Squeaky wheels: Friction-generated sound supports auditory differentiation and scaling of rotating ellipse shapes.

Abstract

Acoustical analysis indicates that sounds generated as the rims of ellipses rotate against a fixed contactor vary regularly with ellipse shapes (defined by minor-to-major axis length ratios), potentially supporting human ability to differentiate and scale the shapes. In four experiments, we documented human ability to do so. Experiment 1 demonstrated reliable and ordinally correct shape judgments. Experiment 2 showed equivalent judgments over rotation speeds (10, 15, 20 rpm), suggesting reliance on relational information in the acoustic signal. Experiment 3 (using scalar judgments) and Experiment 4 (using multiple-choice judgments) tested perceptual learning effects. Some improvement occurred in both experiments, with a moderate advantage for multiple-choice judgments. Individual variability was notable across all experiments: Individual correlation magnitudes (actual vs. judged shape) ranged from .00 to > .9. Past research revealed associations of shape with impact noise; the current experiments are the first apparent demonstrations of human ability to associate planar object shape from friction-generated sound. Results are interpreted as consistent with Gibson's theory of information-based perception. (PsycINFO Database Record

Haptic Distance Ratio Estimation: The Geometry of Space Within the Hands

“…It is interesting that similar large individual differences also occur for analogous visual judgments of distance ratios (see Figures 3 and 4 of Norman et al., 2016). Furthermore, when participants are asked to make judgments about the shape of elliptical objects (that have differing extents or distances in orthogonal directions) from friction-produced sounds, large individual differences also emerge (Cabe, Bochtler, & Neuhoff, 2018). While the exact source of these individual differences is certainly not obvious at the present time, it is clear that the responsible factors are not limited to any particular sensory modality.…”