Sunday, December 27, 2009


by Richard Crews
Although we often think of memory as a single mental process, there are clearly many different aspects or parts--the processes, for example, we call "remembering," "recognizing," "memorizing," and "recalling."

Psychologists differentiate three kinds of memory. The quickest is "sensory memory." It happens inadvertently and lasts a fraction of a second. We are all familiar with it. For example, there is an explosive sound; instantly we seem to listen to it again: "What direction did it come from?" "How far away was it?" "Was it a gun shot? The backfire of a car? A clap of thunder?" This is sensory memory in action.

"Short-term memory" lasts a little longer--up to a few minutes. It enables us, for example, to carry on a conversation. But we have to focus our minds on the sensory input in a certain way--we have to "pay attention"--in order to gather the onward-marching parade of experiences into short-term memories.

Finally, psychologists speak of "long-term memory." This consists of stories and images that have special emotional weight or that we have practiced a lot. We may be able to recall them for days, weeks, or months--perhaps even for a lifetime.

What are the memory difficulties of old age? (At 72 this is the question that particularly concerns me.)

Laying in long-term memories is surely more difficult. I can recite a poem I learned in high school, remember principles of chemistry I learned in college, but learning comparable material now so that I can recall it days or weeks later is much harder. I learn lines for a play by going over them a hundred times; when I was 20 or 30, a few repetitions would have sufficed. There are mnemonic tricks I can use such as finding rhymes or obscene associations, but even with all the help I can give myself, it takes much longer these days to file something into long-term memory so that I can recall it days or weeks later. (Periodic practice recalling the material at intervals of days and weeks is important, but it always was.)

Short-term memory seems, perhaps, to be affected less than long-term. I can confidently remember, nearly as well as I ever could, a shopping list of six or eight items as I head out the door (without writing them down), or a name or telephone number for a few minutes. I am confident that a scheduled event a few hours or a few days away will pop into my head when needed, though I am careful to put extra effort into getting it--and keeping it--on my mental calendar.

The encroaching deficit of sensory memory is subtle. I notice it most in a phenomenon I have experienced more and more in recent years, a phenomenon I call "absurd associations" or "false recognitions." Perhaps you have noticed this too. For example, as I am driving, I pass a sign that seems to say (in the glance I get), "Slats." In the first instant I am satisfied with this, but then immediately puzzled (and perhaps amused): it is unreasonable that a sign should read "Slats." If I can, I look back to study the sign more closely--it says "Stable." I believe this mis-reading results from a deficit of sensory memory. A few years ago I would have had half or three-quarters of a second to replay the glance I got and compare it with an array of imagined possibilities, that is, to measure it against a series of words (and contexts) and select a more reasonable reading. Now I do not seem to have enough time; perhaps the length of time allowed for sensory recall is briefer, or perhaps the evaluative associations are slower--I don't know.

Are there "cures" (or at least "treatments") for the memory deficits of advancing years? Yes and no. First and foremost is acknowledgment of the problem--recognition and acceptance that cognitive decline and other mental and physical changes in old age are inevitable. But with this, one should accept or appreciate that old age is an honorable state: after decades of competitive hustle one has earned the right to sit on the mountaintop and enjoy the view.

On the other hand it can be useful to know that the brain is plastic and adaptable throughout life. Further, that one tends to lose mental skills one does not practice: practicing memorizing or problem solving can preserve--even enhance--ones abilities.

In addition to practicing mental skills, particularly in social or emotionally stimulating situations, there is an "attitude" one can practice that minimizes memory and other cognitive deficits. I call it "hyper-vigilance." In younger years we learned that when we had to drive a car under the influence of alcohol, we should be extra careful, extra attentive--extra vigilant. And one can practice using that same mental state in daily life to counteract some of the effects of mental aging. Another analogy (to the driving-while-tipsy experience) occurs to me since I am presently Christmasing with family near Lake Tahoe. The hyper-vigilance of which I speak is like the extra care and attention one takes when walking on ice or hard-packed snow. One can practice using this mental attitude all the time.