Visual performance on detection tasks with two targets

Horizontal visual lobe boundaries were measured using a single type of target for one-target and two-target detection tasks. The range of sensitivity for two targets was found to be smaller than for one target. Also, for the two-target task, when the targets were on opposite sides of the fixation point and only one target was detected, the presence of the undetected target affected the boundary. These results suggest that further work is necessary to understand the usefulness of single-target lobe area data for multiple-target search tasks. A significant correlation was found between the boundary for one-target detection and performance on the two-target test.