Abstract

Berkeley suggested that “touch educates vision,” that is, haptic input may be used to calibrate visual cues so as to improve visual estimation of properties of the world. Here, we test whether haptic input may be used to “miseducate ” vision, causing observers to rely more heavily on misleading visual cues. Human subjects compared the depth of two hemicylindrical bumps illuminated by light sources located at different positions relative to the surface. As in previous work using judgments of surface roughness, we find that observers judge bumps to have greater depth when the light source is located eccentric to the surface normal (i.e., when shadows are more salient). Following several sessions of visual judgments of depth, subjects then underwent visuo-haptic training in which haptic feedback was artificially correlated with the “pseudocue ” of shadow size. Although there were large individual differences, for half of the subjects, visuo-haptic training significantly increased the weight given to pseudocues, causing subsequent visual estimates of shape to be less veridical. We conclude that haptic information can be used to reweight visual cues, putting more weight on misleading pseudocues, even when more trustworthy visual cues are available in the scene.

Citations