A change commonly found in older persons is a general tendency for responses to external stimuli to be slowed. The document includes a review of theoretical approaches to the explanation of slowing on cognitive tasks that occur with age, and reviews the methodology of a two-part experimental study of 45 subjects. The study reports a letter-matching reaction time task to investigate the relative contributions of attentional factors, pathway effects, and motivational factors to the overall slowing seen with age. Older subjects (mean age 63.5) are found to be more accurate than younger subjects (mean age 20.0) who demonstrate greater speed but more errors. Feedback is shown to affect performance on the part of younger subjects who report pacing themselves. Statistical treatment of the data by cost benefit analysis indicates no significant difference in the time course of costs and benefits between younger and older subjects. (Author/SBP)