9 Virtually all cognitive tasks that require effortful

processing are thought to require working memory. There are a range of models of working memory,10,11 but most are variants of the Baddeley model.9 Regardless of the view one adopts, there is no question that working memory declines with age, particularly the processing or central executive component, as evidenced by the data presented in Figure 1.12,13 Hasher and Zacks14 have emphasized the Inhibitors,research,lifescience,medical role of inhibition, rather than working memory, in age-related cognitive declines. They proposed that older adults are less effective at inhibiting irrelevant information than young adults. They argue that working memory capacity is not limited with age, but rather is filled with “mental clutter” so that capacity appears to be diminished. Older adults are assumed to be particularly deficient Inhibitors,research,lifescience,medical in a deletion operation in working memory whereby irrelevant information is efficiently discarded when it is no longer needed. There is considerable evidence that older adults have difficulty inhibiting irrelevant information in working memory.15-18 There is Inhibitors,research,lifescience,medical also evidence that older adults have difficulty in flexibly deploying mental resources and/or switching among different tasks. Two good everyday examples

that require task switching are day-trading stocks and piloting an airplane. Both the day trader and airline pilot must constantly shift attention among various indicators and adjust their behavior accordingly (eg, trade a stock or adjust altitude). There is considerable evidence that older Inhibitors,research,lifescience,medical adults have difficulty

switching from one operation to another AZD8055 mouse relative to young adults,19-21 with older adults showing larger time costs for switching between tasks (or metaphorically, reloading mental software) than young adults, Inhibitors,research,lifescience,medical when compared with receiving repeated trials on the same task. Another process that is important for many cognitive tasks, but particularly long-term memory tasks, is the ability to connect a memory event to a context. For example, an older adult may remember that he was told to take shark cartilage to improve his/her arthritis. What the older adult may not remember is whether they were instructed Rolziracetam to do this by a personal physician or were told to do this by a friend who had just read it in the popular press. Thus, the older adult may find they remember a fact, but not the source of the information.22,23 This decreased ability to bind target information to source or context is a problem for older adults in long-term memory tasks24-26 as well as working memory.15 Finally, there is no question that long-term memory declines with age (Figure 1). Problems with decreases in speed, working memory, switching, inhibition, and binding could all contribute to poor long-term memory.