Hyperstereopsis is attenuated by the addition of secondary visual cues

Abstract

AbstractPurpose Telestereoscopic (or hyperstereo‐) viewing which increases effective interocular distance has been a subject of interest since Helmholtz’s pioneering work. Increased disparities and vergence alter 3D‐space perception. In particular, apparent egocentric distances decrease, owing to the increased vergence (Priot et al., 2010; Rogers, 2011). This study sought to investigate how the enrichment of stimulus information influences its perceived distance.Methods We assessed distance perception through open‐loop pointing before and during exposure to a telestereoscope in three stimulus viewing conditions: i) a red pinpoint of light (pinhole) providing vergence cue only; ii) a red cross with randomized diameter preventing size cue, providing vergence and some accommodative cues and iii) a real‐size coin slide providing vergence, accommodation, relative‐ and familiar‐size cues.Results Before exposure (normal viewing), we observed an improved perceived‐distance accuracy induced by enriched stimulus information. During exposure (with vergence discrepancy), we found that, on average: i) telestereoscopic viewing altered perceived distance; ii) this effect was modulated by the stimulus viewing condition; iii) the mean slope of the perceived distance of the cross stimulus vs. its physical distance was not different from that predicted by vergence changes according to Helmholtz’s scaling theory; and iv) the hyperstereo effect was attenuated by the enriched stimulus information.Conclusion We ascribe the attenuation of hyperstereopsis by the addition of secondary visual cues to a down‐weighting of vergence contribution relative to those of the other cues.