A decline in performance on the Digit Symbol Substitution test related to aging is well documented. There is no agreement on the reason for the decline, however. In part, the lack of consensus with regard to changes on the test may be attributed to the limitations imposed by comparing groups on a single performance measure. In the present study, three forms of a Symbol‐Digit Substitution task that varied in difficulty level were administered to 125 persons between the ages of 30 and 92. On all forms there was a clear performance decline associated with age. The differences observed among the age group were interpreted as evidence for a change in a sensorimotor component and in two information‐processing operations: Symbol encoding and visual search.

No abstract

Administered three forms of a Symbol‐Digit Substitution task to normals, 16 to over 80 years of age, to schizophrenic and other hospitalized groups. Their data are presented for normative purposes. The three forms vary in difficulty and provide a measure of visual information processing ability, Clinical and research implications of the data are discussed.

Administered block designs that varied according to two parameters, Task Uncertainty and Perceptual Cohensiveness, to 83 persons 49 years of age or older. Performance was adjusted to remove motor speed differences. Performance changed significantly over the age span as a function of Task Uncertainty. From 49 years up, performance did not change as a function of Perceptual Cohesiveness. An analysis that included a group of 20 persons 30 years of age or younger yielded an interaction of Age and Perceptual Cohesiveness. From 49 years on, analytic or image segmentation processes do not seem to change, but other information processing becomes slower.

Age-related changes in auditory temporal processing were investigated using a two-tone flutter-fusion paradigm. Ten elderly and ten young subjects (mean age 71.3 and 22.2 years, respectively) listened to pure-tone pairs at six discrete interstimulus intervals (ISIs). The duration of the second tone (T2) was held constant at 100 ms. The duration of the first tone (T1) was variable. Subjects were instructed to adjust the duration of T1 at each ISI until they perceived flutter or fusion. In both groups, when critical T1 duration was plotted as a function of ISI, the curve was best described by a negative exponential equation. Elderly subjects demonstrated higher critical T1 durations and thus their curve was shifted to the right when compared to the young group. These results are similar to those found in flutter-fusion experiments in vision. We hypothesize that decrements in temporal processing in elderly individuals may not be a modality specific phenomenon. Our results suggest a common underlying mechanism for temporal processing in audition and vision.