This article originally appeared in The Time of Your Life special section, Spring 2016.

The 25th annual Older Americans Conference is 9 a.m. to 1 p.m. Wednesday, May 18 at the Elks Lodge (4131 Pine Road NE, Bremerton). Is is free and open to the public.

BY TERRYL ASLA

Human beings are not cans of soup. There’s no expiration date when you magically become “old.” Still, the most widely used definition of “old” remains age 65, the calendar age that for most of the 20th century was the point in life at which Americans became eligible for Social Security.

But it turns out there was no scientific reason for government officials to choose that particular age.

Social Security was set up during the darkest days of the Great Depression and officials back then were focused on setting up a national pension system that would encourage older men to leave the struggling job market. A historian who studied U.S. retirement history, William Graebner, reported that before officials settled on age 65, they considered going as young as age 50 and as old as age 70.

After the National Institute on Aging (NIA) was created in 1974, research on aging in this country began in earnest. Most NIA aging research applications defined “old” as aged 60 or 65 years and older. This further solidified calendar age in the minds of scholars and the public.

But as research progressed, it became apparent people over 65 years of age weren’t all alike. In an effort to avoid comparing apples to oranges, researchers tried dividing old age into three stages: the young-old (aged 65-74), the old (aged 75-84), and the very old (aged 85-plus). That didn’t work so well either. Some researchers reported that the three age groups still appeared to be made up of both the healthy and unhealthy, even among the very old.

In 2010, Robert Butler, MD, founding director of the National Institution on Aging, admitted “there is nothing magical or scientific about 65 …or any other number in defining old age.”

So what is “old?”

All definitions of everything, not just the concept of “old,” are based on classification systems developed by human beings. It’s how we make sense of the world. “This is a newspaper.” “That is a car.” “He is old.” The important thing to remember about classification systems is that they need to accurately define groups of things or people that share the same characteristics.

In the case of “old,” a meaningful classification is one in which everyone who is said to be “old” shares most of the same characteristics.

Beginning in the 1980s, some researchers in the fields of sociology and psychology suggested dividing later life in two. So, besides childhood (the first age) and middle age (second age), they proposed a third age (the well elderly or “wellderly”) and a fourth age (the “illderly”). So, older adults, regardless of their calendar age, who are in relatively good health and socially engaged may be said to be in the third age. The fourth age is typified by the onset of all the negative stereotypes of old age: failing health and increasing social isolation.

What makes this new classification system so useful is that it compares apples to apples. Membership in the fourth age is based on measurable losses in three or more of the following: vision, hearing, mobility, cognition, strength, and physical illness. So, someone can be classified as being in the fourth age when they are still in their 50s if, for example, they have early onset Alzheimer’s disease. Or, like some of my friends, can still be in the third age even when they are well up into their 90s. Calendar age has nothing to do with it.

Four ages theory can be extremely useful if you are concerned about a parent, friend, or loved one. If they exhibit three or more of those losses, then they should be encouraged to seriously consider the need for additional assistance. Adapting a home to meet changing physical needs, participating in restorative exercise programs that target mobility and strength losses, moving closer to their caregivers — these are the kinds of things that can help them prolong their quality of life, independence, and sense of aging successfully.

Not sure if a friend or loved one is in the fourth age? In 2013, I reported on my findings from a small study that included comparing driving a vehicle and membership in the third or fourth ages. I found that participants in the third age, who had none of the losses listed above, still drove regularly. Those on the cusp of the fourth age (one to two losses) tended to self-restrict their driving and avoided driving at night. Those in the fourth age no longer drove at all and were dependent on others for transportation.

My findings were supported by the kinds of losses leading to driving cessation reported in the driving safety research literature. Bear in mind that driving cessation may not be a valid indicator in all cases. Some healthy people don’t drive at all, or only rarely, because they choose not to or don’t need to. They may live in an urban village where everything is within easy walking distance or in a community that has great mass transit. Likewise, some individuals in the fourth age may continue to drive a vehicle simply because they have no other option or even out of sheer stubbornness.

At age 71, Asla is still in the third age. In addition to writing for peer-reviewed academic journals, he is a reporter for the North Kitsap Herald and assistant editor of Kitsap Military Times.