Effects of haptic feedback on the perception of ambiguous visual stimuli
Touch has the potential to affect the interpretation of visual cues to depth. Three experiments are reported investigating the effect of single point haptic feedback (Phantom + Reachin API) on depth reversal for the Mach card and hollow-face illusions. In experiment 1 perspective, stereo and touch cues all affected perception of the Mach card. Touch was not as effective as stereo in resolving ambiguity but did facilitate the perception of concave stimuli. When shown in reverse perspective, both stereo and touch were needed to overrule the percept of convexity. Experiment 2 used reverse perspective stimuli, adding rigid rotation as an addition visual cue. Touch and stereo were again effective in disambiguating the stimulus but motion was not. Experiment 3 used the hollow-face illusion and showed that stereo, touch and orientation (upright/inverted) all interacted in affecting perceived convexity. There was some evidence for learning, with the seen face more like to appear concave after touch than before. Stylus visibility was found not to affect the interpretation of depth. The results are interpreted as evidence that, while touch does not necessarily resolve visual ambiguity, it can affect the interpretation of visual depth cues and may be particularly effective in combination with stereo.