High-precision capture of perceived velocity during passive translations

▪ During passive transport, participants point continuously to a previously viewed target (white ball mounted at shoulder height) ▪ Intuitive task to perform; less likely to be biased by cognitive influences ▪ Participants instructed not to attend to their own velocity, only to the perceived location of the external target ▪ Following analysis, we recover perceived velocity in absolute, real-world units (m/s) ▪ Requires the assumptions that the initial target location is accurately perceived, and that all pointing errors can be attributed to errors in perceived self-motion (Loomis & Philbeck, in press) ▪ Continuous pointing has been previously used for: ▫ Distance perception (Loomis et al., 1992) ▫ Perception of rotation (Ivanenko et al., 1997; Siegler et al., 1999) ▪ Never used as an explicit measure of instantaneous translational velocity ▪ Same method used in Campos et al. (2008) to show that the characteristic pointing behavior seen during actual translation is not present when subjects imagine themselves moving