Influence of the size of the field of view on motion perception

Efficient navigation requires a good representation of body position/orientation in the environment and an accurate updating of this representation when the body–environment relationship changes. Such updating is based on the ability to correctly estimate the speed and amplitude of body displacements. Because navigation in virtual worlds often relies on the sole visual information, we investigated to which extent the size of the field of view (FoV) affects two basic aspects of motion perception: (i) the perceived amplitude of rotations about the body vertical axis (Experiment 1) and (ii) the perceived speed of forward translations (Experiment 2).Concerning the perception of rotation amplitude, we found that visual flow information gives rise to inaccurate and very variable estimations, with a systematic underestimation of rotations larger than 30°. We also found that the accuracy of the estimations does not depend on the size of the FoV and that horizontal FoVs larger than 30° do not improve the performance. Concerning speed perception, central FoVs smaller than 60° gave rise to an underestimation of the visual speed. On the other hand, occluding the central area leaving only peripheral visual information available induced a systematic overestimation of visual speed, even when only the central 10° of vision was occluded. Taken together, these results suggest that large FoVs are not required to estimate the amplitude of visual rotations about the vertical axis of the body, whereas central FoVs of at least 60° are advisable when speed perception relies on visual flow information.