Visual, tactile and visuo-tactile perception of acceleration and deceleration
Monica Gori, Alessandra Sciutti, Marco Jacono, Giulio Sandini, David Burr
Last modified: 2008-05-13
Psychophysical studies suggest that the human visual system is more sensitive to speed than acceleration (the temporal derivative of velocity). Although there exist some studies on visual perception of acceleration and deceleration, very few exist for tactile discrimination and none for visual-tactile perception of acceleration. In this study we investigated visual, tactile and bimodal perception of acceleration-deceleration by measuring speed discrimination over a wide range of transient speeds (from 6.8 to ~ 454 cm/secĂ‚Â˛). The stimuli were physical wheels etched with a 10 c/deg sinewave profile that could be seen, felt or seen and felt at the same time. Subjects were presented in two separate intervals the standard stimulus, of fixed of 13 cm /sec and the comparison test which a stimulus which arrived at different final velocities with maximal acceleration (454 cm/secĂ‚Â˛). Subjects were required to evaluate in 2AFC protocol which interval contained the faster movement, using only visual, only tactile or bimodal information. We found similar PSEs among visual, tactile and bimodal tasks considering all the different accelerations. Moreover we investigated the difference between deceleration and acceleration and the integration of bimodal signals characterized by opposite direction of motion. Our results suggest that transient velocity signals are analyzed in a similar way by visual and tactile systems.