By J. D. Ratcliff
WORRY about your memory? Go into a room and forget what you came for, go blank on names mislay things? Something on the tip of your tongue, but you can’t pry it off? Don’t fret. You are perfectly normal. Said psychologist Gordon H. Bower of Stanford University: “It is the nature of the mind to forget-and the nature of man to worry about his forgetfulness.”
Actually, you have a prodigious memory. In a few cubic inches your brain stores much more information than can be stored in a large computer installation costing millions. Further it can do things that would stump any present-day computer: remember how burning leaves smell, or how a chocolate sunder tastes. One researcher calculates the brain’s storage capacity at one quadrillion bits of information-that’s a million times a billion: with such capacity, said Harvard’s John Merritt, “no one has ever filled the pitcher to overflowing.” It isn’t surprising that we occasionally forget; it is a wonder that we are able to store and retrieve so much.
Memory is an awesome process that has long fascinated, inquiring minds, only recently, however has there been a concentrated effort to define measure and work out its mechanics. Neuroanatomists, psychologists, molecular biologists biochemists and others are involved. Most agree that there are at least two types of memory. Short-term may least only seconds (you look up a telephone number and remember it long enough to dial). Long term is stored probably for life.
Short-term memory is severely limited. You can hold one seven-digit telephone number, but not three or four. And changes are that if you get a busy signal, you will have to look up the number again. As you read this you store words in short-term memory, at the end of the sentence you extract meaning and discard the words. But if a short-term item is encountered often enough-your own zip code, the name of a new neighbor-it will be moved into permanent storage in long-term memory. A meaningful situation, a reliable reference point, assists in the transfer. A chess grand master can glance at a board as a game is adjourned and days or weeks later recall positions of pieces, exactly-because they are in logical sequence. But place the pieces in a random pattern, and the master remembers positions no better than the rest of us.
Long-term memory is the consummate wonder. Once a bit of information gets in, it apparently is there for life. You may have difficulty retrieving it, but it is there. If a native tongue is not used for ten years-say, by an adopted Vietnamese child in Kansas – all knowledge of it may seem lost. But a few weeks in Vietnam and he will again be fluent. The knowledge was stored in long-term memory. We are unconscious of the vast amount of information we have stored, but under special conditions it can be brought to the surface. Hypnosis enabled a bricklayer to recall exactly an unusual pattern in a wall he had laid 40 years earlier. A middle-aged man described his first-grade schoolroom in minute detail.
Dr. Wilder Penfield, the great Canadian brain surgeon, in the process of surgical treatment found where certain records of memory are stored. With a low-voltage probe he touched various points in patients’ brains. The tickle of electricity activated storage areas and brought back events long “forgotten.” One woman heard Christmas carols in a church in Holland she had attended as child; another relived the birth of her child 20 years before.
From present evidence, there is no single storage area in the brain. Indeed, each memory appears to be stored in a number of places. As much as half the human brain has been removed without serious impairment of memory. Yet a blow on the head or a strong electric shock erases it-how far back depends on the severity of the blow, or the strength of the shock. Then the more recent. This is particularly striking in children. A severe concussion may eliminate half the child’s vocabulary, with the words then gradually returning in the sequence in which they were learned.
Association-relating an object or an individual to a particular scene-appears to aid in retrieval. Says psychologist Fergus Craik of the University of Toronto: “we fail to recognize the man who smiles at us at a bus stop, but would have had no difficulty if we had seen him at his usual place behind the fish counter.” For years researchers thought memory was entirely an electrical phenomenon: reverberating circuits reactivating old memory channels. Today, provocative studies suggest that, while short-term memory is electrical long-term is chemical.
Psychologist James V. McConnell, at the University of Michigan, used as research subjects planarians (common flat-worms) found in creeks and ponds. He flashed a light, then gave them an electric shock which caused them to contract. Soon the worms learned to contract whenever the light flashed. McConnell ground them into a worm puree and fed this to cannibalistic untrained worms. These cannibals then responded twice as often to the light flashes as McConnell expected-although they had never been shocked.
Another researcher go similar results with goldfish, using food rather than shock as a training agent. The late Dr.George Ungar, of Baylor University, tried the idea on rats. In cages with light and dark rooms, the rats got an electric shock when-ever they entered the dark rooms. In a few days they learned to avoid them. Then he minced the rat brains and shot this soup into mouse brains. Normally, mice spend about 80 percents of the time in the dark, but after the shots it went down to only 30 percent of the time. What all this suggests is chemical transfer of learning.
What chemistry is involved? Dr. Holger Hyden, a neuro-biologist at the University of Goteborg in Sweden, suspected that RNA (ribonucleic acid) was responsible. RNA determines what kind of proteins shall be produced and in what amounts, or nerve cells, produces protein molecules which can modify these cells so they can store bits of “memory” information. To test the possibilities, he derived an elaborate experiment whereby “right-handed” rats were trained to become “left-handed.”
Once they had stored this knowledge in memory, Hyden removed their brains and stared dissecting neurons under a high-powered microscope. Next came chemical analysis: the proteins produced by RNA had increased in amount and their shape and activity had changed.
So at the moment it appears possible, at least, that the so-called brain-specific proteins play an important part in memory. Another recent experiment may add strength to this theory. Mice were instructed to perform a task. Then they were given an antibiotic which blocks production of protein within the body. The result? They forgot how to perform the task.
If memory is chemically stored how is it retrieved? Here we reach the great darkness-though there is interesting speculation. The mysterious electrical activity of the brain (brain waves) may play a role in activating memory, just as Penfield’s electrical probe did. Note that even the most brilliant people recall virtually nothing of early infancy, a time when electrical activity of the brain is poorly organized. Also, brain waves alter during periods high mental activity and during sleep. Are they simply a scanning device, seeking stored knowledge?
Some people have extraordinary retrieval powers. A few rare individuals can look at something and have total recall of minute details. Toscanini was reputedly able to study a symphony score and file it away in his memory perfect to the last note. The Shass Pollaks a group of Jewish memory experts, exactly memorized the 12 volumes of the Babylonian Talmud. A young teacher in her 20s, formerly at Harvard, who prefers to remain anonymous, can study a page of poetry for a few moments, even in a language she does not understand, then recite it either forward or backward. As a student, she memorized whole texts before examination time. Can anything be done to improve memory? A great amount of research is under way on mind-sharpening drugs. Several experimental drugs appear to be at least mildly helpful, suggesting that far better ones will one day be found.
Memory loss is one of the main worries-and irritations-of aging. Why the loss? Perhaps one reason is that after age 35, something like 100,000 brain neurons perish each day, never to be replaced. Also, brain arteries harden, reducing nourishment. The elderly’s biggest trouble is retrieving stored knowledge, searching out some fact in the dark recesses of the mental attic. Though they have difficulty with recent events, many insist they recall the distant past with crystal clarity. Psychologists are dubious. Mostly, they believe, memories of long ago are kept fresh by frequent recall.
Studies at the Veterans Administration Hospital in Buffalo suggest that the failure of short-term memory in the elderly may trace, in part, to oxygen lack. Because of hardening arteries or a poorly pumping heart, sufficient oxygen does not get to the brain. A 1969 study reports that 13 patients (average age: 68) spent two 90-minute sessions a day for two weeks, breathing pure oxygen under pressure. Scores on short-term-memory tests shot up. Moreover, subjects appeared to hold these gains for considerable periods after oxygen treatment stopped.
“Perhaps the best advice,” said Professor Craik, “is to keep mentally active by reading, observing, learning. The brain responds to exercise. Memory fall-off is far less in the intelligent, mentally active person than in others.”
By J. D. Ratcliff