Speed Matching Interaction between Visual and Tactile Motion

The goal of the present study is to explore the speed discrimination interaction between visual and tactile motion during unimodal tasks and crossmodal tasks. Fifteen participants performed four speed reproduction tasks that included a tactile-tactile task, a visual-visual task, a tactile-visual task and a visual-tactile task at various speeds. Participants were asked to remember the standard stimuli speed and match the stimuli speed with the standard stimuli speed. The present study showed that both visual discrimination speed and tactile visual discrimination are underestimated relative to the standard speed at relatively high speeds during unimodal tasks. The present study suggests that speed matching is processed similarly in both the visual and tactile sensory systems. Moreover, the present study demonstrated reciprocal interactions between the processing of visual speed matching and tactile speed matching. Visual speed stimuli positively affected tactile speed matching, whereas tactile speed stimuli disrupted visual speed matching at relatively high speeds. Interestingly, visual speed stimuli can calibrate the tactile speed discrimination, but not vice-versa. A possible explanation is that the perceptual system is organized such that speed stimuli input from visual modalities receive a higher weight in the interaction process than speed stimuli input from tactile modalities. The reciprocal interactions between visual and tactile speed matching modalities directly support the view that at some point in the motion processing stream, these two modalities have partially overlapping substrates.