A Group and Individual Analysis of the Relationship between Age and Information Channel Capacity of Adults. Final Report.

This study was designed to measure adult performance as related to age. Using methodology derived from information theory, information processing ability was measured with the individuals performing as a communication system. Fifty-five school teachers, ranging in age from 20 to 66, served as subjects. In four groups, the subjects judged the sizes of dark squares on a light background in five tests. Images were projected onto a screen, under controlled timing conditions. Performance declined as age increased in four of the tests. In two tests this decline was statistically significant (p<.05). It was anticipated that the methodology employed would provide asymptotic values of channel capacity, indicating that maximum information processing capacity had been reached. However, the methodology used did not provide such a measurement. A secondary phase of the study explored individual differences. Eleven subjects exhibited considerable variability, particularly a difference in their ability to judge size of squares and the placement of a dot in a grid pattern. The study confirmed earlier studies indicating some decline in performance with aging but pointed up the abilities of older adults to make precise judgments even under severe testing conditions. (Author)