Memory

Memory has been more widely studied than almost any other aspect of cognitive function, other than intelligence. After arthritis, memory problems are the second most frequent complaint among older adults. From age 45, the overall frequency of complaints of memory problems increases steadily. Despite this seeming consensus on memory complaints, the literature reveals a discrepancy between subjective reports of memory failure and objective abilities. Subjective impressions are a poor predictor of objective performance. In part this discrepancy reflects the nature of memory and how we asses our own competency. The efficiency of memory may differ considerably depending on the situation or context. For example, reliable recall of visual images such as paintings may be accompanied by a relatively poor recall of verbal words.

Older adults perform less well on tasks involving encoding, retention, and retrieval of information. Currently we know very little about when competence first begins to decline, how rapidly these declines progress, and how decline in memory efficiency compares with other cognitive functioning. Although there is a general progressive trend in poorer memory performance with age, the magnitude of changes in memory competence are small and marked changes in ability do not generally occur until late in life.

As people grow older, the rate at which they process information declines. Information processing has three phases:

encoding: getting information into the system
storage: retaining information
retrieval: recalling information.

Encoding is particularly vulnerable to age. As we age it takes more time to encode information than when they were younger. This slower rate of encoding may be due to changes in our vision, hearing and other senses that reduce the efficiency of memory. The slower rate of encoding is most likely the reason for age-related declines in short-term memory. Two types of memory tasks are recall (retrieving information) and recognition (matching information). Regardless of age, recognition is better than recall. Recognition does not decline as we age, but recall does. Long-term memory may decline as we age depending on the extent to difficulty with encoding information. Very long-term memory which spans months or years is relatively stable until well after age 70.