Detection and Localization 1 Running head: DETECTION AND LOCALIZATION Target detection and localization in visual search: A dual systems perspective

The dual visual systems framework (Milner & Goodale, 1995) was used to explore target detection and localization in visual search. Observers searched for a small patch of tilted bars against a dense background of upright bars. Target detection was performed along with two different localization tasks: direct pointing, designed to engage the dorsal stream, and indirect pointing, designed to engage the ventral stream. Results included (1) target detection was influenced more by orientation differences in three-dimensional space than by pictorial differences, (2) target localization was more accurate for direct than for indirect pointing , and (3) there were performance costs for indirect localization when it followed target detection, but none for direct localization. This is consistent with direct localization having a greater dependence on the dorsal visual system than either target detection or indirect localization.