Using Immersive Virtual Reality to Examine How Visual and Tactile Cues Drive the Material-Weight Illusion

Abstract

Weight illusions provide a compelling demonstration that prior experience affects perception. Here we investigated how the expectation-inducing modality affected the Material-Weight Illusion (MWI), where dense-looking objects feel lighter than less dense-looking objects. Participants lifted equally-weighted polystyrene, cork, and granite cubes whilst viewing computer-generated images of the cubes in virtual reality (VR). The representation of the object in VR was manipulated to create four illusion-inducing sensory conditions: visual differences only, haptic differences only, congruent visual-haptic differences, and incongruent visual-haptic material differences. Although an MWI was induced in all conditions, whereby the polystyrene object was reported to feel heavier than the granite object, the strength of the MWI differed across conditions, with haptic material cues having a stronger influence on perceived heaviness than visual material cues. These results are consistent with optimal integration theories of multi-modal perception, highlighting that perception reflects individual cues’ reliability and relevance in specific contexts.

Does ‘virtuality’ affect the role of prior expectations in perception and action? Comparing predictive grip and lifting forces in real and virtual environments

“…Independent testing has supported the accuracy of the trackers for accurate visualization, even in more vigorous activities (Merker et al, 2023). and granite (unaltered density 2.67g/cm3) (Figure 4)will be used to elicit the MWI (as used in Naylor et al, 2022). The three boxes (5 x 5 x 5 cm) have been hollowed out and lead weights have been placed inside to ensure they all weigh exactly 123g (+75g).…”