Abstract
[Purpose] The size of the useful visual field changes dependently on the attentional state. Previous works have shown that training reduces the influence of the central task, suggesting extending the size of the useful visual field. For the training effect performing the dual tasks perhaps play an important role while the presentation of the central and peripheral stimuli may also play a role. In order to examine whether training extend the size of the usual visual field without peripheral task, we conducted psychophysical experiments to investigate the effect of training on the field size without any peripheral task. [Experiment] We used a rapid serial visual presentation (RSVP) task as the central task and detection of a gradual luminance increment with a temporal Gaussian profile as the peripheral task to measure the size of the usual visual field. The peripheral stimulus was presented at locations with different distances from the fixation point. There were two training conditions: dual-task training and single-task training. During the dual-task training, the participants were asked to perform the central RSVP task and the peripheral detection whereas they were asked to do only central task during the single-task training. The peripheral stimulus was supra-threshold stimulus in the single-task training sessions so that the participant can detect easily if asked to do. Based on the detection rate as a function of the eccentricity, we defined the size of the useful visual field within which the detection rate was higher than 62.5% before and after each type of the training sessions. [Results] The performance of the peripheral task improved and the useful visual field size was expanded with a significant amount both after the dual-task and the single-task trainings. These results suggest that the useful visual field size increases by the training even without performing a peripheral task.