Effect of prior headlighting experience on ratings of discomfort glare

This study investigated the effects of prior headlighting experience on ratings of discomfort glare from headlamps in an actual driving situation. Specifically, discomfort glare ratings given by West Germans who had recently arrived in the United States and were, presumably, used to the relatively low levels of glare associated with headlamps in West Germany were compared with ratings given by U.S.-born subjects. The West German subjects reported significantly more discomfort than did the U.S. subjects. This finding is in agreement with the so-called range effect, in which subjective judgments are affected by the range of available stimuli. Consequently, the present findings support the hypothesis that discomfort glare ratings are affected by prior visual experience.