The Effect of Background Luminance and Contrast upon Visual Search Performance

There is much experimental evidence, generally supported by everyday experience, to show that more light means better sight. For example, it has been shown that higher levels of illumination lead to reduced contrast thresholds, improved visual acuity, and decreased visual reaction time. However, much of the relevant laboratory work has involved the use of stimuli carefully imaged upon the fovea of the eye. We now wish to extend this knowledge by using a visual task which, although it includes foveal vision as an important component, also critically requires the use of peripheral vision.