Aging and the maintaining of preparation.

In an experiment on 25 women and men who were selected for short RT (reaction time) and who ranged from 22 to 85 years of age, some loss of preparation was found over an interval of about 4 seconds during which there was constant momentary probability of signal occurrence. The central finding was that the amount of loss remained invariant with age. Numerous controls were used to ascertain that this stability was not an artifact. Support was given to the contention of Loveless and Sanford [14] that the markedly longer RTs found for older than for younger subjects when long, constant PIs (preparatory intervals) are employed is not attributable to difference in ability to maintain preparation. However, the reason for the foregoing effect remains in question. Loveless and Sanford [14] suggest that older subjects may not be able to control preparation in some more general sense and suggest that they do not use available timing information. However, similar findings on schizophrenics have been explained in terms of inhibitory effects with increased redundancy [1]. A method is suggested for eliminating the artifactual shortening of RT at the longest waiting period found in studies using the present method for measuring the maintaining of preparation.