HUMAN HEADING ESTIMATION DURING VISUALLY SIMULATED CURVILINEAR MOTION

Recent studies have suggested that humans cannot estimate their direct ion of forward translation (heading) from the resulting retinal motion (flow field) alone when rotation rates are higher than similar to 1 d eg/sec. It has been argued that either oculomotor or static depth cues are necessary to disambiguate the rotational and translational compon ents of the flow field and, thus, to support accurate heading estimati on. We have re-examined this issue using visually simulated motion alo ng a curved path towards a layout of random points as the stimulus. Ou r data show that, in this curvilinear motion paradigm, five of six obs ervers could estimate their heading relatively accurately and precisel y (error and uncertainty <similar to 4 deg), even for rotation rates a s high as 16 deg/sec, without the benefit of either oculomotor or stat ic depth cues signaling rotation rate, Such performance is inconsisten t with models of human self-motion estimation that require rotation in formation from sources other than the flow field to cancel the rotatio nal flow.