A primary purpose of this work is to investigate the relationship between age and concentrative ability. Using laboratory studies of task-unrelated imagery and thought (TUIT) it was determined that old adults had fewer TUITs than young and middle-aged adults. One possible explanation for this result is that age and concentrative ability are directly related. Laboratory investigations are needed to confirm this apparent increased concentrative ability in the older population. An experimental procedure was developed where subjects are asked to repeat messages presented to one ear (shadowing) while ignoring simultaneous messages in the other ear. High concentrative ability is demonstrated by equivalent shadowing performance with and without simultaneous (and different) messages in the other ear. Last year it was reported that after controlling for differences in intelligence, hearing loss, and monaural shadowing performance that age and concentrative ability are inversely related. With increased age there was an increase in dichotic shadowing errors. The decrease in concentrative ability with increased age was especially prominent in old adults who had been hospitalized within the prior two years and were on prescription medication. This year a more precise investigation was begun into the moderating effect of health. Also begun was an investigation in the specific source of the apparent age-related loss of concentration, reduced ability to control attention or to discriminate among inputs.
