Modulation of tactile motion by intra- and inter-modal manipulation

The perception of tactile motion is essential for our daily interaction with objects. Tactile motion perception has been studied by using stimuli featuring real or apparent motion. Research on tactile apparent motion has conventionally manipulated the perceived direction of the motion using 2 non-repeating or more than 2 repeating stimuli. Here, we report the modulation of perceived motion direction at different alternation rates by manipulation of the tactile stimulus onset asynchrony (SOA) between the left-to-right and right-to-left stimuli in 2 alternately and repeatedly presented vibrotactile stimuli generating ambiguous apparent motion (Experiment 1). The present study also reports that the perceived direction of tactile motion could be modulated by manipulation of the timing of additional static sounds even when the SOAs of the tactile stimuli are equal (Experiment 2). We discuss the temporal differences in the effects of intra- and inter-modal stimulus timing on tactile motion perception.