For a dozen years after I watched my father vanish into the black hole of Alzheimer’s dementia I feared I too would end up with the Big A, as a frightening and frightened empty shell of a man.

I can admit to this fear now because I’m pretty much over it. I don’t think it’s likely that I will go that way; there is more than one path to the exit.  Well past the age at which my father’s decline became noticeable, I have my own set of annoying health issues; they do not seem to impair my ability to write a blog, recognize an old friend, fill out a tax form, or research aging memory on line.

But I do occasionally forget where I put my glasses, or whether I turned off the tea kettle before I went to bed. It’s on that kind of “senior moment” memory lapse that I have something to say.  Dementia is relevant here only to remind us what normalcy is not.

Gerontologists tell us that the momentary failure to recall something is a normal part of aging, not necessarily a harbinger of dementia.  Agreed.  Some doctors also tell us that increasing forgetfulness is normal because our powers of memory, the synapses and brain cells that do the work, naturally weaken as we age.  Not exactly.

Okay, how can senior moments be normal if increased forgetfulness is not?  Simple.  Senior moments are not forgetfulness.  To explain that apparent paradox I turn to A White Paper on Aging from Johns Hopkins Medical Center:

“The mental processes required to remember newly acquired information are the same as those needed to retrieve memories from long ago, something most older people do well. This implies that older people retain the capacity to recall recent events, but the new information is not being recognized as important or is being discarded instead of stored.  Some researchers interpret this to mean that occasional memory lapses may result from a failure to pay close attention to the information rather than an inability to remember. Thus, it appears that forging new memories depends in large part on staying interested, active and alert.”

In other words, our memory does not get weaker as we age; we simply don’t bother to record trivial information. And as any mature adult knows, there’s a lot of trivial information out there.

Even young people discard unneeded data. In my twenties I could forget (that is, not bother to remember) the names of four people I casually chatted with at a party, but I would probably remember the name of the idiot I argued with and certainly the name of that stunning woman who listened to the argument.

We do not forget how to walk or ride a bicycle or recite the alphabet or tie our shoes or speak our mother tongue because learning each of these things was the most important event going on in our lives at the time and we gave it our full attention.

We remember the names and faces of our high school classmates because socializing, making friends, was a key element of our maturing process at that period of our lives.

And we remember exactly where we were and what we were doing at moments of great national trauma—the beginning of a war, a terrorist attack, an assassination—because the event gripped us completely, grabbed our attention and therefore registered it in memory.

People in mid-life, working, studying, commuting, earning money and spending it, raising children, are plugged in to the world and are compelled to pay attention.  Then most of us retire and relax; one day becomes the next; and as the years go on, the total amount of everyday information we encounter piles up, repeated events and routine automatic tasks we’ve performed thousands of times are regarded as trivial, not worth a thought and therefore not worth a memory—until we need to remember one of them an hour later.

To avoid the senior moments we can obey the doctors and engage in some kind of activity that demands input from a wide-awake brain. But we don’t need to worry about those moments. It’s only if we forget new and important information that really interested us need we wonder whether a more sinister process may be going on inside.

Now I will put my glasses on my desk. Pay attention.