Gaze direction affects linear self‐motion heading discrimination in humans

Abstract

We investigated the effect of eye-in-head and head-on-trunk direction on heading discrimination. Participants were passively translated in darkness along linear trajectories in the horizontal plane deviating 2° or 5° to the right or left of straight-ahead as defined by the subject's trunk. Participants had to report whether the experienced translation was to the right or left of the trunk straight-ahead. In a first set of experiments, the head was centered on the trunk and fixation lights directed the eyes 16° either left or right. Although eye position was not correlated with the direction of translation, rightward reports were more frequent when looking right than when looking left, a shift of the point of subjective equivalence in the direction opposite to eye direction (two of the 38 participants showed the opposite effect). In a second experiment, subjects had to judge the same trunk-referenced trajectories with head-on-trunk deviated 16° left. Comparison with the performance in the head-centered paradigms showed an effect of the head in the same direction as the effect of eye eccentricity. These results can be qualitatively described by biases reflecting statistical regularities present in human behaviors such as the alignment of gaze and path. Given the known effects of gaze on auditory localization and perception of straight-ahead, we also expect contributions from a general influence of gaze on the head-to-trunk reference frame transformations needed to bring motion-related information from the head-centered otoliths into a trunk-referenced representation.

Binding body and self in visuo‐vestibular conflicts

“…Ni et al . () observed that gaze straight ahead dominates body straight ahead in determining the reference frame to define the perceived direction of motion, thus demonstrating that preference for vision‐related variables extends also to the definition of space with respect to the self. The tendency to overweigh visual input fits with our participants’ high congruence judgment, independent of the condition.…”

Multisensory Integration in Self Motion Perception

“…Numerous psychophysical studies have investigated how visual and vestibular signals contribute to self-motion perception , MacNeilage et al, 2010, Cardin and Smith 2010, Cuturi and MacNeilage 2013, Ni, Tatalovic et al 2013, Frank, Baumann et al 2014, de Winkel, Katliar et al 2015, but less research has examined adaptation or calibration across these signals. Characterizing perceptual adaptation provides unique insight into both the architecture and dynamics of physiological processes underlying perception.…”

Young children can use their subjective straight-ahead to remap visuo-motor alterations

“…Therefore, the effects are likely attributable to differences in the spatial information processing strategy used at different ages rather than differences in visual stimuli or task comprehension. The present study did not monitor gaze, a known source of spatial distortions in eccentricity estimation 1,49,50 , but assumed that the participants would keep their gaze on the target, the only item in the virtual environment. Since the targets were placed at the same FoV-centered coordinates in the two "direction" levels, the study assumed equally distributed eye movements; however, without eye-tracking data, an association between the effects found and differences in the pattern of eye movements cannot be excluded.…”