The outer limits: How limiting the field of view impacts navigation and spatial memory

Abstract

Many optical devices limit the amount of the visual field that can be seen at any one time. Here we examine how these limits on Field of View (FoV) impair the ability to integrate visual information and make navigational decisions. Participants wore field-restricting goggles with separate groups fitted with either a 40° or 90° horizontal FoV. Subjects actively explored a maze-like environment over the course of 12 search trials. For each search trial, subjects were given a specific target and asked to find it as quickly as possible. The time and path walked to the targets were recorded on paper. Between each trial subjects were blindfolded and led to a new location in the environment. After the search trials, they completed a set of spatial memory tasks that included sketching a map of the search area, and judging the relative direction of and distances between objects. Search performance was measured by average walking speed, which was determined by dividing the path length by the search time for each trial. Participants with the narrower FoV walked significantly slower to the targets, but they increased their speed over time. Independent raters, who judged the sketch maps on layout, scale, and geometry showed a significant preference for the maps of the wide FoV group over the narrow FoV group. However, there was no effect of FoV for the relative direction and distance estimation task indicating a limited impact on the memory of locations of objects in the environment. In contrast, the results suggest that FoV restriction has a significant impact on the spatial representation of the layout of one's environment that needs to be considered in the design and use of devices that augment or enhance vision.

Footnotes

 The authors gratefully acknowledge the support of the Ontario Centres of Excellence and the CIHR Strategic Training Program in Vision Health Research.