Effects of Divided Attention on Peripheral Target Localization

摘要

Designers and users of helmet mounted displays often assume that single eyedevices reduce operator workload relative to dual eye devices by allowing two tasks to be performed simultaneously, one by each eye. In other words, the two eyes are assumed to constitute separate attentional channels. To test this assumption, we implemented a modified version of the useful field of view (UFOV) paradigm to measure the effects of dichoptically divided attention on dual task performance. Subjects localized a peripheral target within a semicircular region of 30 radius while simultaneously performing a foveal task. The degree of difficulty of the experiment was manipulated by varying the foveal task workload and the number of clutter (distractor) items in the periphery. The foveal and peripheral tasks were either presented to the same eye (monocular viewing) or different eyes (dichoptic viewing). Peripheral target localization performance was essentially perfect at all eccentricities for all the non clutter conditions: monocular and dichoptic viewing, low and high foveal task workload. Introduction of peripheral clutter caused a significant deficit in localization performance that increased with increasing target eccentricity. Similar to the non clutter conditions, there was no difference in performance between monocular and dichoptic viewing. Thus, we find no evidence to support the assumption that dividing attention between two eyes allows dual tasks to be performed more efficiently than when attention is divided within the same eye, implying that the two eyes do not constitute separate attentional channels.