Abstract
Previous research has found that both the useful field of view (UFOV) and contrast sensitivity (CS) are effective predictors for accident risks, especially for aged drivers. It has been shown that with increased age observers exhibit slower processing of visual information in the central and peripheral visual field, especially when dividing their attention to two simultaneous tasks in different locations in the visual field, and less tolerance when perceiving objects under low contrast conditions. The current study aimed to investigate the effect of contrast on UFOV among younger adults. 18 participants (age M = 21.8, SD = 3.8) were first tested on their contrast threshold, using a contrast detection task (CD) with their dominant eye. They then went through a modified version of UFOV tests developed by Richards, Bennett, and Sekuler (2006) under three different contrast levels, with the highest Michelson contrast level set to 0.3, the low level set at CD threshold level, and the medium level set as the logarithmic midpoint between low and high contrast levels. In the UFOV tests we measured focused attention, focused-peripheral attention, and divided attention in three subtests, at five eccentricities (4, 8, 12, 15, and 20 deg) on display duration threshold using the BEST-PEST algorithm. The contrast was kept constant within a block of subtest. All variables were run as within-subjects variables and the order of contrast blocks were counterbalanced across participants. Significant main effects and interactions were found for all independent variables in all three subtests. In the focused attention task, performance deteriorated with decreased contrast, which was predicted. Surprisingly, in both the focused-peripheral task and divided attention task, the medium contrast level resulted in the lowest threshold in display duration, indicating a non-monotonic effect of contrast on the UFOV test.
Meeting abstract presented at VSS 2014