To the editors:

The title of William von Hippel’s review does not mince words. Aging is related to infirmity. Researchers may debate the mechanisms governing how we grow old, discussing the relative influences of free radicals, immunological dysregulations, cellular breakdowns, and other processes behind theories of programmed or non-programmed aging, but few would dispute the fact that we become less physically resilient as we age. Cognitive and physical functioning most often peaks in early adulthood, and declines in the ensuing decades.

Aging is linked to decline, and researchers study this declining trajectory for several reasons. We need to know the differences between issues of primary aging, those changes that result from biological decline as a result of the aging process, and those caused by disease processes that are closely linked with chronological age. We also need to understand the reasons why some people show declines earlier than others, whereas others appear years younger than their chronological age. Social scientists have joined the scientific quest to determine factors that speed up or slow down the aging process. Researchers have found that psychological stress is related to cellular aging, as seen in the shortening of telomeres, the genetic material at the end of a chromosome that protect the strand and allows the cell to replicate. Mothers with chronically-ill children have telomere lengths that appear nearly a decade older than their less-stressed, same-aged peers whose children are not disabled.¹

Studying infirmity of aging is important, but I doubt that this topic is what attracted most social gerontologists to the field. The reason lies in another statement aspect of aging that was also recognized in this review. As strongly as von Hippel asserts that aging is associated with infirmity, he also states that aging is associated with wisdom. This is a fundamental paradox of aging. Old age is associated with infirmity—weakness and decline—yet it is also associated with wisdom, a characteristic highly prized across most cultures. The definition of wisdom often includes adept judgment and decision-making that displays a deep understanding of life.² People who are wise are able to tackle difficult problems, and difficult problems are often highly emotional, and often social, in nature. Social gerontologists have documented that older adults are often more adept at solving contentious interpersonal conflicts.³ For example, in one study, older and younger adults were given social problems and asked how to resolve them.⁴ Afterwards, coders rated the quality of their responses; they rated the responses of the older adults as superior to those offered by the younger adults. Other studies find that older adults more often chose strategies that reduce emotional tensions in their own social relationships, which may contribute to why they often report higher levels of relationship satisfaction than younger adults.⁵

These findings have intrigued and baffled social gerontologists for years. Why would wisdom increase with age when the brain that is responsible for these complex thoughts, and particularly the region most responsible for reasoning skills, is declining? Why do older adults often report higher levels of emotional well-being than younger adults, yet cognitive decline is related to increases in depressive symptoms?⁶ Turning to the literature on animals for answers is difficult. Researchers have learned that the wisdom of older female elephants lies in their more adept detection of the threat in a lion’s roar compared to younger herd members.⁷ Yet older age in humans is related to poorer discrimination of different emotions for both auditory and visual stimuli,⁸ so the wisdom of age in humans is not explained by superior emotion detection skills.

In another study, older age was related to fewer social partners in monkeys; loss of resources (such as strength) most likely explained this phenomenon.⁹ This reason, then, could also explain the age-related decrease in social partners observed in human studies, as opposed to the explanation offered by socioemotional selectivity. Socioemotional selectivity theory posits that socioemotional motivations change as a result of time perspective, and a growing awareness that time left in life leads people to prioritize time with close social partners instead of expanding their social network.¹⁰ If age-related patterns of social partners were the only studies of socioemotional selectivity theory, an alternative explanation of reduced energy levels or lack of other resources may seem like a more parsimonious explanation. Yet other studies have shown that older adults, when asked to imagine that they were guaranteed twenty more years of life, started making social partner choices that mimicked those of younger adults.¹¹ When younger adults were asked to imagine a shorter life span, they made choices that paralleled those normally selected by older adults.¹² These findings indicate that younger adults will choose to spend more time with a close social partner whose time with them is growing shorter; for older adults, their time is growing shorter with every one of their social partners.

The above example underscores the need to continue to study these processes, and the mechanisms underlying them. We need to continue to observe changes with age in longitudinal studies, documenting changes in emotional processes that rule out explanations that age differences are an artifact of cohort effects—those differences based on how people were raised and other factors unique to specific generations. Lack of physical energy, and other reductions in resources associated with infirmity are undoubtedly contributing to changes related to age, and it makes sense that brain-related decline and energy depletion would contribute to age-related decline. What makes less sense is that wisdom—one’s attitude and perspective about life—would appear during a time in life marked by decline. This paradox is what excites and challenges social gerontologists, and this is the great mystery of aging that motivates them to search, and re-search, for answers.

Susan Charles