ABSTRACT
Proprioceptive information may be used in combination with visual information to disambiguate the optic flow scale problem for walking observers, i.e., the observation that spatial action rests on scale-ambiguous patterns of visual stimulation (c.f., Sedgwick, 1973; Eriksson, 1974; Stoppers, Smets, & Overbeeke, 1989,1992; Wertheim, 1990). The present experiment investigated whether people can match the “speed of their legs” to the “speed of their eyes”: subjects adjust the speed of a treadmill they walked on to match a flow pattern presented in front of their feet. Also it was investigated whether the proprioceptive match depended exclusively on kinematic information (the speed of the feet) or that other factors like the effort of walking also influence the proprioceptive speed estimate.
