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ZHENG BIAN, GEORGE ANDERSEN; Aging and the effect of size information on the control of braking. Journal of Vision 2014;14(10):240. doi: 10.1167/14.10.240.
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© ARVO (1962-2015); The Authors (2016-present)
Previous studies have found observers used tau-dot to regulate braking (Yilmaz & Warren, 1995; Fajen, 2005). Braking performance was also affected by global optical flow and edge rate information (Fajen, 2005). Previously we examined age-related differences in the use of ground texture information in braking regulation (Bian & Andersen, 2013, VSS). In the current study we examined age-related differences in the use of size information in regulating braking. Observers included twelve younger (mean age = 21.6) and twelve older adults (mean age = 73.1). On each trial, observers viewed computer generated 3-D scenes (visual angle = 106.4° × 73.9°) simulating driving on a roadway towards three stop signs at a constant speed. During the first 5 seconds, the observers did not have control over the brake. Five seconds later, observers heard a warning tone indicating the control input was allowed. Their task was to apply smooth and continuous braking and stop as close as possible to the stop signs. The initial time-to-contact (3s, 3.5s, or 4.0s), initial speed (40kmph, 60kmph, or 80kmph), texture on the ground (no texture or 32×64 checkerboard) and size of the stop signs (0.2m or 0.6m each side) were manipulated. The texture was blocked and counterbalanced across observers in each age group. The mean stop distance relative to the stop signs, standard deviation of stop distance, crash rate and distribution of tau-dot were collected. We found that older observers had larger mean stop distances and lower crash rates when large stop signs were presented. Younger observers, however, had higher crash rates when large stop signs were presented. In addition, regulation of tau-dot varied as a function of size for younger but not older observers. These results, taken together, suggest that older observers may use size information differently for determining distance than younger observers in braking regulation.
Meeting abstract presented at VSS 2014
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