Abstract
Peripheral vision shows poorer performance than central vision for various visual tasks. Although there are many studies that have used artificial stimuli or human faces, little is known about the recognition of daily objects in peripheral visual fields. In the present study, we investigated recognition of facing direction of objects in peripheral vision. The task was to judge the facing direction (left or right) of static objects briefly presented at the location either in the left or right peripheral visual field along the horizontal meridian. Stimuli were daily objects (humans, animals, cars, motorcycles, and arrows), presented at either 5 or 20deg of eccentricity, and sizes 3 or 6deg visual angle. The results showed that participants judged facing direction of objects correctly when their size was relatively large. However, decreasing stimulus size made the recognition performance worse when the objects faced toward participants' point of gaze than when the objects faced away. In an additional experiment, we investigated whether the phenomenon occurred only in peripheral visual fields along horizontal meridian or not. Stimuli were presented at a total of eight peripheral locations; left, right, upper, lower, and upper / lower left and right from the participants' point of gaze. An arrow and bar figure was used in this experiment. We adopted the bar figure to examine the judgements for objects with no directional information. The results showed that recognition performances were lower for the arrow facing toward the point of gaze than for that facing away at all eight peripheral locations, and that the bar appeared as the arrow facing away. These results indicate new interesting characteristic of object recognition in peripheral vision; in peripheral visual fields, representation of object is view-dependent, or more precisely, dependent on viewer's point of gaze.