Abstract
Our perceptual system combines visual and haptic (touch) information to optimize estimates of 3D properties including slant (Ernst, Banks & Buelthoff, 2000) and size (Ernst & Banks, 2002). However, the integration of visual and haptic cues to material properties has been largely overlooked. Previously (Kerrigan, Adams & Graf, 2010), we reported that observers' gloss perception is modulated by the haptic properties of friction and compliance: objects that feel hard and smooth are perceived as glossier than those that feel soft and rubbery. The current study demonstrates that visual and haptic gloss cues are integrated at a perceptual level, resulting in visual-haptic metamers. First, observers completed an odd-one-out task with uni-modal stimuli. This allowed us to equate visual and haptic stimulus parameters in terms of discriminability. Observers then performed a similar odd-one-out discrimination task with visual-haptic objects. When visual and haptic gloss cues were varied in opposition to each other (e.g. visual gloss increased but the object felt more rubbery, relative to a standard stimulus), discrimination performance was poor: the two cues' effects partially cancelled out, resulting in reduced perceptual changes. This contrasted with improved discrimination when visual and haptic gloss cues varied concordantly (e.g. objects that were visually more glossy were also harder and more slippery). Although friction and compliance are not reliable predictors of gloss across our environment, the visual system appears to know and use a probabilistic relationship between these variables to inform material perception.
Meeting abstract presented at VSS 2014