Integration of serial sensory information in haptic perception of softness.

Redundant estimates of an environmental property derived simultaneously from different senses or cues are typically integrated according to the maximum likelihood estimation model (MLE): Sensory estimates are weighted according to their reliabilities, maximizing the percept’s reliability. Mechanisms underlying the integration of sequentially derived estimates from one sense are less clear. Here we investigate the integration of serially sampled redundant information in softness perception. We developed a method to manipulate haptically perceived softness of silicone rubber stimuli during bare-finger exploration. We then manipulated softness estimates derived from single movement segments (indentations) in a multisegmented exploration to assess their contributions to the overall percept. Participants explored two stimuli in sequence, using 2–5 indentations, and reported which stimulus felt softer. Estimates of the first stimulus’s softness contributed to the judgments similarly, whereas for the second stimulus estimates from later compared to earlier indentations contributed less. In line with unequal weighting, the percept’s reliability increased with increasing exploration length less than was predicted by the MLE model. This pattern of results is well explained by assuming that the representation of the first stimulus fades when the second stimulus is explored, which fits with a neurophysiological model of perceptual decisions (Deco, Rolls, & Romo, 2010)

Influence of visual and haptic delays on stiffness perception in augmented reality

Visual delays are unavoidable in augmented reality setups and occur in different steps of the rendering pipeline. In the context of haptic interaction with virtual objects, it has been shown that delayed force feedback can alter the perception of object stiffness. We hypothesize that delays in augmented reality systems can have similar consequences. To test this, we carried out a user study to investigate the effect of visual and haptic delays on the perception of stiffness. The experiment has been performed in an optimized visuo-haptic augmented reality setup, which allows to artificially manipulate delays during visual and haptic rendering. In line with previous results, delays for haptic feedback resulted in decreased perceived stiffness. In contrast, visual delays caused an increase in perceived stiffness. However, the simultaneous occurrence of delays in both sensory channels led to a partial compensation of these effects. This could potentially help to correct stiffness perception of virtual objects in visuo-haptic augmented reality systems

空中ジェスチャ・インタラクションにおける触覚提示の高臨場感化および安定化に関する研究

Tohoku University昆陽雅司課