Cost of Dividing Attention Moderated by Contrast Level
43.4076, Monday, 18-May, 8:30 am - 12:30 pm, Pavilion
John Plummer1, Rui Ni1; 1Department of Psychology, Wichita State University
Previous research shows that dividing attention between multiple targets in the visual field occurs frequently in everyday activities. The cost of dividing attention has been found to be affected by various environmental factors. One such factor is the contrast of the targets from their background (Plummer & Ni, 2014), which has important applications for activities such as nighttime driving. In the current study, contrast was manipulated to examine its effect on the cost of dividing attention. Eighteen younger adults participated in the study, whose contrast sensitivity thresholds were first measured on a contrast detection task. They then completed a modified version of the UFOV test (Richards, Bennett, & Sekuler, 2006), which consisted of measures of peripheral-focused attention and divided attention thresholds at three eccentricity locations (4, 12, and 20 degrees) from the center of the screen. These measures were carried out at 5 different contrast levels, with the high set at .3 Michelson contrast, the low at each participant’s contrast detection threshold, and the other three intermediate levels evenly distributed along a logarithmic scale. The threshold of display duration was derived using the best PEST procedure for each eccentricity under each contrast level. Attention cost was calculated by subtracting the threshold scores of the peripheral-focused attention from those of the divided attention task. The results showed that, for both tasks, thresholds increased with increased eccentricity and decreased contrast. The interaction between contrast and eccentricity was significant for the peripheral-attention task, but not for the divided attention task. Consistent with previous research, the current study found increased cost of dividing attention under low contrast conditions. Our results might explain the increased accident risks associated with driving under low visibility conditions, such as at night or in fog.