Effects of monocular occlusion on neural and motor response times for two-dimensional stimuli.

Previous studies have shown that there are advantages associated with the simultaneous use of both eyes to view two-dimensional stimuli. To investigate further this binocular advantage, three experiments were conducted using male and female names presented on a video display as stimuli. In the first experiment, simple reaction times (RT's) were found to increase by about 6% as a result of monocular occlusion. In the second experiment, visual evoked response (VER) and P300 implicit times were also found to increase as a result of occlusion. The third experiment confirmed these results and investigated the sensitivity of evoked potential techniques to changes in stimulus complexity. The three experiments demonstrate that monocular occlusion does have a significant effect on processing speed for two-dimensional visual stimuli. The major portion of this effect (62%) is manifest at the level of the visual cortex, and is not perceived by subjects as significantly increasing the mental workload associated with generating responses to these stimuli.