Abstract
An important aspect of successfully interpreting the environment is the ability to quickly process dynamic visual cues, such as motion parallax (MP). However, older adults often require longer temporal processing intervals to recover various types of visual information. Here we investigated how age affects neural processing times for the perception of depth from MP. To assess processing delays, we measured threshold stimulus durations (stimulus-onset-asynchrony, or SOA) necessary for younger and older observers to make motion and depth judgments without interference from a high-contrast pattern mask. In four different conditions, observers made judgments about motion direction or depth phase. In two separate motion conditions observers reported the direction of relative image motion or the direction of motion of a translating stimulus window. In two separate MP conditions, observers reported the depth phase of a two different translating stimuli (4 deg/sec) that both required a pursuit eye movement. Threshold SOAs in each task were found using an adaptive procedure. Pursuit accuracy (gain) for a translating target (4 deg/sec) was also measured. Overall, observers required briefer SOAs to recover motion information, compared to SOAs in the MP tasks. In all four tasks, older observers had higher SOAs than younger observers. In the motion conditions, older observers' SOAs were 2-3 times higher than younger adults'. In the MP conditions, older observers' SOAs were 60-65% higher than younger adults'. This age-related difference in SOAs in MP conditions is smaller than might be expected, given the much larger difference in processing times in the motion conditions. There was no difference in pursuit gains between younger and older observers. These results indicate that the processing time required to recover depth from MP is not as affected by age as is the time required to recover motion information.
Meeting abstract presented at VSS 2016