In this article we will discuss about the effects of aging on human memory, intelligence and creativity.
First, let’s consider the impact of aging on memory. Research on working (short-term) memory indicates that older people seem able to retain about as much information in this limited-capacity system as young ones seven to nine separate items. Some findings, however, suggest that the ability to transfer information from working memory to long-term memory may decrease with age. Also older persons perform more poorly than younger ones if they must carry out several working memory tasks in a row; in such cases, older persons show a greater decline on later tasks than young persons.
This suggests that as we grow older, our ability to deal with the effects of proactive interference – interference with materials we are currently entering into working memory from materials we entered earlier declines. However, such effects may also stem from a general slowing in cognitive systems that occurs with increasing age.
Turning to long-term memory, it appears that with increasing age there may be some declines in episodic memory (memory for events experienced by an individual and associated with a particular time and place), while semantic memory (general knowledge) remains largely intact. Procedural memory the information necessary for performing many skilled actions seems to be the most stable of all.
Other findings indicate that memory for relatively meaningless information such as nonsense syllables or paired associates does decline with age. But when the information being committed to memory is meaningful for instance, has some connection to an individual’s everyday life differences between younger and older persons are much smaller and in some studies do not appear at all.
Overall, then, it appears that unless we experience serious illness (e.g., Alzheimer’s disease), we retain many of our cognitive abilities largely intact. Further, and perhaps even more encouraging, it appears that even modest declines in memory can be avoided through “mental exercise” engaging in activities that require us to think, reason, and remember.
Why do declines in certain aspects of memory occur with increasing age? Partly, it seems, because of changes in the brain. As we age, total brain weight decreases—5 percent by age seventy, 10 percent by age eighty, and 20 percent by age ninety. Further, the frontal lobes, a region of the brain that plays a key role in working memory, seem to experience greater loss of neurons than other areas of the brain. The hippocampus, too, shows increasing damage over time; and, this region of the brain also plays an important role in memory.
Interestingly, women seem to experience smaller changes than men in brain structure as they age. This suggests that female sex hormones may protect women’s brains from age-related changes.
In the past it was widely believed that intelligence increases into early adulthood, remains stable through the thirties, but then begins to decline as early as the forties. This view was based largely on cross-sectional research that compared the performance of persons of different ages on standard tests of intelligence.
Results indicated that in general, the older persons were, the lower their scores tended to be. Unfortunately, such cross-sectional research suffers from a serious drawback. Differences among various groups of participants can stem from factors other than their respective ages, such as differences in education or health.
The results of studies using longitudinal procedures have yielded a more positive picture than the earlier cross-sectional studies. Instead of declining sharply with age, many intellectual abilities seem to remain quite stable across the entire life span. In fact, they show relatively little change until persons are well into their sixties, seventies, or beyond. Moreover, some abilities even seem to increase.
For example, Schaie and his colleagues have tested thousands of people ranging in age from twenty-five to eighty-one at seven-year intervals. Results clearly indicate that various aspects of cognitive functioning (as measured by one standard test of intelligence) remain remarkably stable throughout adult life. Indeed, even at age eighty, fewer than half of the persons studied showed any declines during the preceding seven years.
Only on tasks involving speed of reasoning do there appear to be consistent declines in performance. In view of the fact that drops in performance may reflect slower reaction time which is known to occur with age there is little if any indication of a general decrease in intelligence with age.
Additional findings reported by Finkel and others (1998) indicate that important cohort effects may be involved in age-related changes in intelligence (or in general cognitive performance). These researchers studied several hundred twins in Sweden—individuals ranging in age from their early forties to their mid-eighties. They found that for the younger samples (cohorts), there was little evidence of change in various aspects of cognitive performance over a nine-year period.
For the oldest samples (people in their seventies and eighties), however, some declines did occur. Why? Many researchers would point to the fact that these persons, as compared to younger ones, probably had poorer nutrition and had less formal education as they grew up. If such factors are equated, then, as Schaie (1994) has found, little or no decrements in performance are evident.
While such findings are encouraging, they are not the entire story. Standardized intelligence tests may not capture all aspects of adult intelligence. The distinction between crystallized and fluid intelligence is especially relevant here.
Classroom tests, vocabulary tests, and many social situations in which we must make judgments or decisions about other persons draw on crystallized intelligence. In contrast, fluid intelligence includes our abilities (at least in part inherited) to think and reason. Research focusing on these two types of intelligence suggests that fluid intelligence increases into the early twenties and then gradually declines. In contrast, crystallized intelligence tends to increase across the entire life span.
Similarly, there may be little or no decline in practical intelligence— the ability to solve everyday problems. In fact, it seems possible that such intelligence, which is very important, may actually increase with age. In sum, while there may be some declines in intelligence with age, these are smaller in both magnitude and scope than age-related stereotypes suggest.
Finally, let’s consider creativity the ability to produce work that is both novel (original, unexpected) and appropriate (it works—it is useful or meets task constraints). Does creativity change with age? This is a difficult question to answer, because, this concept is easier to define than to measure. Despite such problems, however, there have been several studies designed to determine whether creativity changes with age.
Cross-sectional research on this issue indicates that, as measured by standard tasks such as coming up with novel ways of using everyday objects, creativity does decline with age. However, other research, focused on the question of when during their lives scientists, authors, poets, and painters make their creative contributions, points to the following conclusions.
First, creativity rises rapidly to a peak, usually in a person’s late thirties to early forties, then gradually declines. Second, the age at which the peak occurs varies greatly by field. In poetry, pure mathematics, and theoretical physics, peaks occur relatively early when people are in their late twenties to early thirties. In psychology and other fields of science, the peak occurs around age forty.
And in still other fields’ history, writing, philosophy the peak may be in the late forties or fifties. It’s also important to note that what seems crucial is an individual’s number of years in his or her field career age, not chronological age. In other words, if people enter a given field later in life, they may show their peak creativity at a later age than if they enter it earlier in life.
It’s also important to note that many famous people made their major contributions when they were in their sixties, seventies, or eighties. Cervantes wrote Don Quixote at age sixty, Monet produced many of his most famous paintings in his seventies, and Michelangelo was designing and painting until his death at eighty-three.
Finally, many famous people show a secondary peak in creativity near the end of their lives the swan-song phenomenon. These works of old age are often shorter and more restrained than the creators’ earlier works, but they often win critical acclaim precisely for this reason, They do it all with less complexity.
Where does all this leave us? With, we believe, an overall pattern of evidence suggesting that few intellectual abilities decline sharply with age. Some do decrease, especially ones closely related to speed of responding. But others remain quite stable over many years, and still others may actually increase as individuals gain in experience. Our conclusion- Aging is inevitable, but our minds can, and often do, remain active until the very end of life.