by Guy Murchie
If lasting memory is thus stored in protein, with the molecules imprinted by thoughts the way tin cans are indented by kicks, the question arose as to how many molecules or cells are needed for memory. It wasn't an easy question but had the interesting consequence that, in seeking the answer, researchers in the nineteen fifties turned seriously to the worm for enlightenment.
They picked the worm because it is not only cosmopolitan enough to be the average in complexity of all animals but also because it is ideally suited to experimentation into basic memory. The particular worm chosen was a half-inch flatworm called a planarian, unique because he is both the lowest creature in the evolutionary hierarchy who has a central nervous system and the highest creature who reproduces by dividing. He also offers a good deal of fascination with his disconcertingly humanoid, cross-eyed look plus a nonchalant capacity to be chopped into as many as six pieces, each of which will grow into a whole new worm. Besides he is probably the simplest creature
possessed of a nerve junction that can reasonably be called a brain. In the laboratory a batch of these worms were first subjected to a bright light, which normally makes them stretch out, then two seconds later they were given a mild electric shock lasting one second, which made them curl up. By the time this light-and-shock sequence had been repeated a couple of hundred times, they had begun to regard the light as a warning and would curl up before the shock as if deliberately bracing themselves against something they had come to fear. Next many of the worms were cut in two and the remainders allowed to grow back into new worms, which were then tested with the light-and-shock sequence. So far it had been presumed that the head ends of the half worms, which contained the original brains and only needed to grow back their tails, would remember their previous training better than would the brainless tail ends that had to grow new heads and brains. But, in fact, the tail ends did about equally well. In some cases the recovered tail ends actually remembered and responded to the light signals faster and better than did the recovered head ends, strongly suggesting that memory does not depend upon a brain.
In a later experiment trained worms were cut not just in two but chopped into hundreds of tiny pieces and fed to worms who had not been trained at all. And the untrained worms who ate the trained pieces began to curl up whenever exposed to training lights, indicating that memory of the training of the chopped-up worms had almost certainly been transmitted to the untrained ones through what they had eaten.
This of course, even more than the previous finding about brainless memory, dramatically supported the chemical theory of memory - including the ancient superstitions of cannibal tribesmen that, if they could only contrive to eat certain parts of a brave enemy, they would become as brave themselves. And there was a noticeable flurry of speculation about the future of education, which could be expected to become more liberalized, with increasing probability that one day an ambitious young man might make himself into an intellectual, if not by literally partaking of a professor, at least more and more likely by regularly taking protein pills containing scientifically filtered RNA or mutated enzymes from tissue purportedly sophisticated or even wise.
As for the question of how many cells are needed for memory, we already know that one cell will do, because we observed in Chapter 9 the one-celled ameba who remembered the prey he had lost several seconds earlier. And we don't need to wait for what we are going to learn in Chapter 12, that a bird's egg, which (like other organisms) was initially one cell, may remember the patterns of stars, the melodies of songs and a great deal more that was sensed, learned and bequeathed by its ancestors - undoubtedly going back for thousands of generations.
ABSTRACT ASPECTS OF MIND
Among other discoveries is the fact that memory can be duplicated and stored in numerous areas of the brain and that sense memories (visual, auditory, etc.) are recordable not only in their respective specialized zones but each item is filed in several distinct (sometimes widely separated) places, a system that may have evolved as a safeguard against local damage. Indeed, although a severe electric shock or a blow on the skull may erase memory, particularly recent memory (the span erased being proportional to the severity of the shock or blow), as much as half the human brain has been surgically removed without noticeable memory loss.
Now a researcher named George Ungar, at Baylor College of Medicine, and his colleagues have advanced from worms through fish to mammals and are claiming to have isolated the first known "mammalian substance involved in the chemical transfer of learned behavior." Specifically this means they have discovered a memory protein named scotophobin (Greek for "fear of the dark"), which was obtained from the brains of rats trained to avoid the shadowy places they normally feel safe in and which, when it is injected into untrained rats, makes them wary of the dark too.
The same team says they have also isolated a compound from the brains of fish trained to avoid two different colors, a completely artificial behavioral trait that can be passed on to other fish by injection. And rather charmingly macabre is their recent experiment in training some 6000 rats to ignore the ringing of a loud bell, then collecting and purifying the rats' brains by repeatedly testing fragments of them on mice and keeping only those portions that made the mice ignore the bell. It was a process not only of distilling the animals' musical memories and pouring them into test tubes but of establishing that the very faintest recollection of a ringing bell has a chemical structure at once abstract and tangible, a chain of six amino acids that can be visualized both as coded sheet music and as the most exquisite of microgeometries.
When I encounter such tenuous abstractions in the seamlike interplace between body and mind, I can't help wondering where ideas come from. If we allow that it really has taken something like five billion years for Earth to evolve mind to its present state, and that mind is now speeding up its development by learning to leap forward in time as well as outward and inward in space, to grapple a little with the unknown, who can gainsay any rate of acceleration it may yet attain toward things still undreamed?
Memory is also an abstraction of abstractions, rather like the group wave, because it is conserved in the chemical patterns inside cells such as brain cells, patterns that survive metabolic changes among the atoms of the molecules composing them, probably even changes in whole molecules. Yet the actual materials that make up these abstract relationships are themselves, in latest analysis, also abstract, being made of "waves of probability" of no determinable concreteness. Space-time-matter itself indeed has, and is, a kind of memory, for anything done by it - any movement or acceleration or physical change of any sort - is recorded in its material position, velocity and orbit - in its exact physical state. This state also is always the sum of its history up to that moment, its present the equal of its total past. And presumably human memory works similarly, what one potentially can recall at any instant being the accumulation of all one's past nerve impulses or chemicomagnetic traces that were strong enough to have left impressions in the "tape" of one's brain cells or in the genes of any kind of cells that could accept such impressions.
Having thus concluded that a single cell (including a sperm or an ovum) is definitely endowed with the possibility of memory, it is easy to see how any offspring might remember the experiences of parents or earlier ancestors. And this brings up the question of the inherited memory that may reside, as we shall see, in an egg, that can enable an animal to navigate across oceans by star patterns and is generally classified as instinct. And another example of instinctive animal orientation is the case of termites inside their houses, building columns in which two teams have been observed a foot apart, each constructing a vertical pillar in the darkness, seemingly without interpillar communication, yet curving the structures toward each other at the same height so that they eventually met to form a perfect arch, which would later support a gallery floor.
The more socially sophisticated animals seem generally to inherit some such maps of the mind, maps that not only enable them to vis
ualize their migratory way but somehow to objectify whatever nest they are assembling or even the pattern of a courtship dance. And senses other than the visual ones are included, so a bird may "hear" in his mind's "ear" the song he wants to sing as well as "feel" in his throat the muscular and other sensations of how to sing it. Such inherited awarenesses give strong evidence also of life before conception, to say nothing of life after death, and demonstrate (as we will see in Chapter 19) that our present earthly consciousness can well be just the finitude phase of our continuing transcendence toward Infinitude.
INTELLIGENCE
The kind of intelligence acquired by animals is naturally different from that of humans and has a far greater component of instinct, which is usually specialized for survival value. An example is the case of double foster parenthood which, despite the indifference wild creatures generally show toward young not their own, was revealed recently in an ornithologist's report of a nest of young Savannah sparrows being raised by parents who happened to be clearly identifiable by their color bands. For just after the little birds were hatched, their mother was killed and eaten by a snake. But the father quickly took on a new wife to help him with the hungry youngsters. The following week the father was also lost, evidently caught by a hawk, whereupon the foster mother attracted a new husband to her nest and the lucky orphans were raised by these two strangers until fledged and flown.
Another instance of specialized, instinctive sensitivity, probably augmented by experience, was that of a pair of foxes with a den in the bank of a shallow stream. One bright April afternoon the mother fox was seen from a nearby house carrying one of her babies in her mouth across the stream to a sheltered spot under a high rock ledge on the other side. And then she appeared with a second baby, and a third, one trip for each. That same night there came a lashing rainstorm which turned the stream into a raging torrent that certainly would have drowned the fox cubs, had they remained in their den. Four days later the vixen carried her family back home to the damp but drying den. Later that spring on two more occasions the mother moved her young ones to high ground and each time within twelve hours the den was flooded. Such natural prescience of stormy weather, possibly through acute perception of dropping barometric pressure, rising humidity, wind direction or other clues is not known among humans to my knowledge.
As for the perennial question of which is the smartest of animals, there is a wide difference of opinion, depending on one's definition of smartness. But at least among animal trainers, who tend to judge intelligence by sensitivity and quickness in learning what will (or won't) bring a reward, something of a consensus (admittedly controversial) seems to be developing. The majority appears to rate the ape, particularly the chimpanzee, as first, then the various monkeys, followed by the raccoon, the porpoise and the pig. The average dog, they claim, although very responsive to man after his long domestication, is generally outwitted by the pig. Then there is the shy fox, followed by the mysteriously independent cat. The crow, next in line, seems to be the brightest of birds, seconded by the parakeet and parrot. Then come the cow, the sheep, the goat, the nervous horse and, in succession, the beaver, the rabbit, squirrel, hamster and other rodents, various barnyard fowl, and so on.
An animal who uses a tool is not necessarily highly intelligent, if he was given it and taught its use by a human. But there are known instances of animals taking to tools on their own iniative, even to the point of shaping them in advance. The best documented case I know is Jane van Lawick-Goodall's account of a chimpanzee who broke off a long, straight twig from a tree, trimmed away its side sprouts and leaves, then poked it deep into a termite nest, after which he pulled it out with a few clinging termites and licked them off as from a spoon. Several young chimps were later seen learning to make and use such termite spoons by observing their elders, suggesting this was likely an example of early cultural evolution handed down from generation to generation, not genetically but by education. The best toolmaker among birds may well be the great spotted woodpecker of England, who cuts clefts in trees, in this case mostly by instinct, and uses them as vises to hold pine cones in place while extracting their seeds.
As for "tools" used without modification, all the apes and many varieties of mammals, birds and insects avail themselves of them, particularly of sticks and stones. Baboons have been known to break open hard-shelled fruits with rocks and use smaller stones to crush scorpions before eating them, not to mention adopting anything from a stick to a corncob as a napkin. Gorillas have been seen using leaves for toilet paper. And elephants to pick up long sticks to scratch themselves where their trunks could not reach, or a branch to switch away flies. A few animals even make tools out of the stolen parts of other animals, as the octopus's habit of using a jellyfish's stinging tentacle to shock and immobilize shrimp for food or, on one known occasion, to halt the attack of a moray eel. And the ubiquitous thorn, sharp and tough, is a natural chisel, needle and nail, being used to dig out tree insects by a Galapagos finch who thus fills the role of a woodpecker, as well as by a shrike who adopts it for a meat hook to hold his prey.
Although a man-made mirror does not qualify as an animal tool, its occasional use by an animal produces not only a reflection of its body but, more interestingly, of its mind as well. This was shown in the case of the lion in California who was brought up in a normal house and evidently regarded himself, if anything, as just another pussycat until the appalling truth was finally forced on him by a full-length looking glass. But a baby giraffe was offered no such help when separated from his sick mother at birth and raised in a zoo pen all alone - with the result that, when he was eventually introduced to her several months later without having ever seen or heard of giraffes, he was terrified. To him, who hadn't the slightest idea there could be any such animal, it must have seemed incredible that this unimaginable
creature could somehow imagine she owned him. Even the human mind depends much more than you would think on the kind of revelation only its reflected image can provide, for it became dramatically evident in several recent cases of abandoned ghetto orphans who reached school age without ever having seen themselves that, without a mirror, not one of them could really be said to have a realistic comprehension of his own existence!
The difference between animal and human intelligence is seen thus as primarily a difference of degree, for even though few animals are capable of realizing that their mirror image represents themselves, most of the great apes learn about reflections from experience almost as readily as does a human child. Indeed learning by experience is observed throughout animal life, even in lowly one-celled protozoa, who often actually try several different responses to their environment before settling on the one that works best. And when any animal repeatedly finds the same behavior successful, he almost inevitably becomes conditioned to continuing it. Such a stable response of course depends on memory too, which appears to evolve in rough proportion to the complexity and longevity of the animal. That is why planarian worms need about a hundred trials to learn how to get through a simple two-fork maze while rats easily learn and remember a single right-left alternation pattern in a more difficult maze, although they rarely can master double alternation such as two right turns followed by two lefts. Yet rats and more advanced mammals usually can solve relatively complex problems involving unfamiliar principles if they have time to learn by experiment, even if the experiment is more accidental than intentional. A case in point is that of an exceptionally imaginative female snow monkey in Japan who discovered, while playing with a potato at the beach, that dipping it in sea water not only cleaned it but gave it a delicious salty taste. She also discovered she could separate wheat grains from sand by dropping the mixture into water so that the wheat floated free, and both discoveries were quickly recognized and adopted by her troop.
When animals are guided by humans they often learn even faster. In fact the rat's capacity to learn was measured recently at a research "rat school," where a class of furry, young "scholars"
who had been given several weeks of intensive instruction in the laws of nature were found to have developed brains 5 percent bigger than uneducated rats, their nerve cells having increased slightly in number but more definitely in size and complexity. And probably the most important single advance they made (which goes for the education of young humans too) was that they learned how to learn!
Obviously there are limits to animal intelligence, assuming a reasonable definition of the animal as it evolves through future eons, presumably under increasing human control. But individual animals, like individual humans, show occasional mysterious flashes of genius, particularly if the animal's intelligence is greatly enhanced by human training, as in the case of the border collie of Scotland, a smallish, black and white breed, now considered the best sheep dog in the world. I heard a story about a border collie named Commodore owned by a sheepherder in Arizona. One evening a nearby rancher saw a column of sheep being driven over a rise by Commodore, who was carrying a man's hat in his mouth. When the dog had neatly penned the sheep, he took the hat to the rancher. Then he turned back to the sheep trail, looking over his shoulder to make sure he was being followed. By heeding the dog, the rancher found the sheepherder pinned under a fallen boulder, in shock but alive. Commodore had known his master was in serious trouble but, being also responsible for bringing his flock home for the night; he took the hat, saw his sheep safely put away, then used the hat to get help. This is the kind of intelligence found in a first-rate sheep dog, who controls his charges not by running and barking but mainly by getting the attention of the flock leader by fixing his eye upon him and holding him mentally with a kind of hypnotic concentration, augmented by subtle anticipatory movements that make him respond in precisely the desired direction.