Abstract
Previous research has shown age-related decrements in the detection of collision events with moving objects (Andersen & Enriquez, 2006). The current study examined whether there are age-related differences in collision detection with fog. On each trial, younger and older adults observed a scene for 3, 5, or 7 seconds. The scene consisted of a simulated ground surface and a ball moving on a straight trajectory towards the observer through four levels of fog. The scene disappeared before the ball reached the observer plane. The contrast was 0.12 for the no fog and 0.03 for the fog conditions at the beginning of the ball's motion. At the end, the contrast was 0.23, 0.37 and 0.51, respectively, during the 3, 5, and 7 second display durations for the no fog condition and 0.04 during all display durations for the fog conditions. The subject's task was to indicate whether or not the object was on a collision path with the observer. On half the trials the display simulated a stationary observer while on the remaining trials the display simulated forward motion of the observer. Results showed that main effects were found for both fog density and age, as well as for duration and presence/absence of egomotion. The ability to detect collisions for younger adults, although significantly reduced when fog was present, was greater than older adults under the highest fog density conditions. High fog density also resulted in decreased performance for short display durations. Both age groups performed equally well during the 7 second scene duration, while older adults were significantly worse than younger adults at detecting collisions during the 3 and 5 second scene durations. These results suggest that when driving under fog conditions, older adults may have an increased risk of crash and require more time to detect an impending collision.
Supported by NIH AG13419-06 and EY18334-01.