Age-related changes in rate of visual information processing

Each of four groups of 12 subjects performed four psychophysical tasks. The age ranges of the four groups were 19-31, 45-57, 58-70, and 71-83 years, respectively. All four tasks required some form of visual information processing: Two were backward-masking tasks; two were temporal-integration tasks. In all four tasks increasing temporal functions over age were obtained, suggesting slower processing rates as age increased. The results support an active processing model of visual perception that interprets duration of visible persistence and duration of interval in which backward masking is effective as indices of the time course of early stages in the processing of stimulus features. The evidences also suggests that backward masking and visible persistence may be mediated by distinct mechanisms that are affected differently by aging processes. A model that conceptualizes the visual system as a multichannel processor is proposed as an explanation for some of the findings.     

Visual information processing in relation to age and to reading ability.

Temporal aspects of early visual information processing were studied developmentally in good and in poor reading male subjects ranging in age from 7 to 13 years. Forced-choice temporal integration and backward masking tasks, respectively, were utilized to assess duration of visual persistence and of relative rate of visual information processing. The results did not reveal differences in either visual persistence or processing rate in relation to reading ability at any age level studied. However, processing rate was found to increase markedly with chronological age in both the good and the poor readers while visual persistence did not vary significantly. The findings were discussed in relation to earlier work and in relation to current theoretical formulations of visual information processing.