Over the past few days, several things have reminded me how important our memories become as we age, and how much we need friends and family to remember with us. First, I read an article by a woman whose sister has Alzheimer’s disease, in which she painfully describes the process and the effect on both of them. More recently, on the anniversary of the 1965 March on Washington to End the War in Vietnam, I have been discussing the political activism of the 1960s with friends who were there with me. Or maybe not.
What emerged was a funny collage of recollections of what may or may not have been the same demonstration. For me, it was a sensory memory of sitting in front of the White House in the cold slush, but it seems there were two demonstrations where people sat in front of the White House in the cold slush, one against the war, and the other to demand government support for the marchers in Selma , which came about a month earlier.
But when we joke about our aging memories, are we being accurate? How much do we actually lose, given normal health?
As we age, our brains do lose neurons, and some of these neurons are in centers associated with memory, particularly the part of the brain that produces a cetylcholine, a neurotransmitter necessary to memory and learning. The hippocampus, another part of the brain associated with memory, loses about 5% with each decade of age. Our memory retrieval becomes less efficient.
However studies show that certain kinds of memory can continue essentially unchanged, including motor memory (driving a car, playing a musical instrument) and semantic memory (information we have learned throughout our lives). As we learn, the dendrites that connect brain cells with each other are strengthened and reinforced. As we age, these can begin to weaken, and we can lose some of the ease with which we can access what we know. So we can temporarily forget the word for an object, but retain the purpose of the object and how to use it. We may forget where we put our reading glasses, but we remember why we need them and how they work.
As we age, let’s remember, we accumulate vast amounts of information, from the words to a song to the Pythagorean Theorem, to the recipe for chocolate chip cookies. It may take us a while to find the memory we want at any given moment as we shuffle through all this, like looking through a card catalog – and you must be aging if you can remember what that is.
A linguistic professor in Germany, Michael Ramscar, looked at some of the research that we lose vocabulary as early as age 45. He found that the researchers were rating the speed with which a word can be retrieved, totally ignoring the size and richness of vocabulary available to the individual. As we age, we slow down – our motor skills, and our memory, among other things. And there are many distractions and stressors which can affect our test performance, and which might at times be greater for older people. But the richness of our knowledge, Ramscar concluded, can help when our memory fails.
But I don’t think this is actually what happened in my reminiscences with my friends. It took us a while to connect memories to events, which is known as episodic memory , and on which aging does have an impact. I remembered the sensation of sitting in the cold slush in Washington, and associated bits like the pleasure of getting a hot drink, and even of demonstrators and police sharing coffee once or twice, but over time these memories had become disconnected from the historical event that led to them. In part, I remembered the things I had brought up in memory and in conversations over the years, and the very act of remembering distorted the memory itself. When we retrieve a memory, the memory of the event gets stored in the brain in place of the original, and the next time I remember the event, I remember it as I recounted it, with whatever distortions and emphases I had added.
But I also remembered this with friends who had shared the experience. I was able to do this despite the fact that we are as far apart as Montreal and California, Massachusetts and Arizona, thanks to the internet and Facebook. With them I was able to attach my memory to an event I had forgotten.
Which brings me to the article about the sister with Alzheimer’s. It is so important to have some people in your life to whom you don’t have to explain everything, who will visualize the same place when you say something happened in the living room or the kitchen. Siblings do this best, but I am so lucky to have friends from 50 years ago. So much of these relationships is shared memories. One of the most difficult parts of aging must be losing the people who are part of our memories. Later in the discussion I wrote about, another friend’s name came up, and I mentioned that I had googled her a few years ago, and found her obituary. Another of us also had learned on the internet that she had died. We are young enough that most of us are still basically healthy, but I don’t look forward to getting such news about more of us.
Losing the people who share our memories is yet another way of losing memories themselves.