The Science of Collective Memory: Rats, Crystals, and the Hundredth Monkey

Evidence for Non-Local Information Transfer in Nature

In 1920, a psychologist named William McDougall began an experiment at Harvard University that would take fifteen years, span thirty-two generations of rats, and produce results so strange that the scientific establishment would spend the next century trying to explain them away.

McDougall was testing Lamarckian inheritance — the discredited idea that organisms can pass on traits they acquire during their lifetimes. His experimental design was straightforward. White rats of the Wistar strain were placed in a specially constructed tank of water. Two escape gangways led out of the tank: one brightly illuminated but rigged with an electric shock, and one dimly lit with no shock. Over time, each rat learned to choose the dim, safe passage. The number of errors — the number of times a rat took the bright, shocking route before consistently choosing the dim one — was recorded.

The first generation averaged over 56 errors before learning the task. McDougall bred from these trained rats and tested their offspring. He repeated this for thirty-two generations.

The results were dramatic and unsettling. By the fourth group of eight generations, the average number of errors had dropped to 20. The rats were learning faster with each generation — as though the memory of the maze was somehow accumulating in the bloodline. Some later generations figured out the correct escape route almost immediately, showing an error rate as low as 20 compared to the original 165 errors observed in the earliest tested rats.

McDougall believed he had demonstrated Lamarckian inheritance. Critics objected that he may have unconsciously selected smarter rats for breeding. The experiment was messy, the controls imperfect, and the implications too threatening to the prevailing Darwinian orthodoxy.

So the experiment was repeated. And this is where the story gets truly interesting.

The Melbourne Replication That Changed Everything

In the early 1930s, a team of researchers at the University of Melbourne — W. E. Agar, F. H. Drummond, O. W. Tiegs, and M. M. Gunson — set out to replicate McDougall’s experiment with rigorous controls. Their study ran for twenty years and culminated in a final report published in 1954.

Agar’s team did everything McDougall should have done. They maintained a proper control group — a line of rats of identical stock that were never trained in the water maze. Each generation, both the trained line and the untrained control line were tested.

The results confirmed McDougall’s finding: rats in the trained line did indeed learn faster over successive generations. But the truly remarkable result was this: the untrained control line showed exactly the same improvement. Rats whose ancestors had never seen the water maze, whose parents and grandparents and great-grandparents had never been trained, learned the task just as quickly as the descendants of trained rats.

The Melbourne team concluded that the results refuted Lamarckian inheritance. The improvement could not be due to training being passed down through the generations, because the untrained line improved at the same rate. Case closed, they said. McDougall was wrong.

But Sheldrake looked at the same data and saw something the Melbourne team had dismissed. Both lines improved. The untrained rats got better at a task their ancestors had never encountered. This is not what standard genetics predicts. If the improvement were due to random genetic drift or unconscious selection for smarter rats, why would it occur at the same rate in both trained and untrained lines? Why would both lines track each other so closely?

Morphic resonance offers an explanation. As more and more rats of the Wistar strain learned the water maze task — first at Harvard, then at Melbourne — they contributed to a growing morphic field. All subsequent rats of the same strain, whether descended from trained or untrained parents, could draw upon this accumulated memory. The field did not care about bloodlines. It cared about similarity. Any Wistar rat, anywhere, would resonate with the experiences of all previous Wistar rats.

The Melbourne team’s “negative result” was, from Sheldrake’s perspective, a positive result for morphic resonance.

Crystal Formation: When New Compounds Learn to Crystallize

The crystal evidence is subtler but equally provocative. Chemists have long observed a curious pattern: when a new chemical compound is synthesized for the first time, it is often extremely difficult to get it to crystallize. The process can take months or years of patient effort. But once crystallization has been achieved in one laboratory, it tends to become progressively easier in other laboratories around the world.

The standard explanation is contamination by seed crystals — microscopic fragments of the original crystals that travel between laboratories on equipment, clothing, or airborne dust. This is plausible in many cases. Crystals are tenacious travelers, and even a single molecule of the right crystal structure can nucleate the growth of a new crystal from a supersaturated solution.

But the pattern persists even in cases where contamination is carefully controlled. And it extends beyond mere ease of crystallization. New compounds sometimes exhibit a cascade of polymorphs — different crystal structures that appear in sequence, each more stable than the last, as though the morphic field is evolving toward an optimal form.

The xylitol case is illustrative. Xylitol, a sugar alcohol now widely used in dental products, existed only as a liquid for decades. Then, around 1942, a crystalline form with a melting point of 61 degrees Celsius appeared. Several years later, a second crystalline polymorph emerged with a melting point of 94 degrees Celsius. After the second form appeared, the first reportedly became impossible to produce. It was as though the morphic field had been permanently altered — the new habit had replaced the old one.

Mainstream chemistry can account for polymorphism through thermodynamic and kinetic factors. But the timing and irreversibility of such transitions — the way a new crystal form seems to “take over” once established — is consistent with the idea of a morphic field deepening its channel, making one pattern increasingly dominant at the expense of alternatives.

The Hundredth Monkey: Myth, Metaphor, and Grain of Truth

No discussion of collective memory would be complete without addressing the hundredth monkey effect — one of the most popular and most misunderstood stories in the consciousness literature.

The original observations were real. In 1953, on the small island of Koshima (a 32-hectare islet off the coast of Miyazaki Prefecture in Japan), a team of primatologists was studying a troop of Japanese macaques (Macaca fuscata). The researchers provided the monkeys with sweet potatoes, which they scattered on the beach. The potatoes were sandy and gritty.

In September 1953, a researcher named Ms. Mito observed a young female monkey, about eighteen months old, doing something no one had seen before. The monkey — later named Imo by the research team — carried her sweet potato to a stream and washed the sand off before eating it. This was a genuinely novel behavior. No other monkey in the troop had ever done it.

Over the following years, the behavior spread — but slowly and through specific social channels. Imo’s mother and siblings adopted it first. Then her playmates. Then their mothers. The propagation followed kinship and friendship networks, exactly as social learning theory would predict. By 1958, most of the young monkeys had learned to wash potatoes, but many of the older adults — those who had no close social ties to the young innovators — never adopted the behavior at all.

The “hundredth monkey” version of this story was created by Lyall Watson in his 1979 book Lifetide. Watson claimed that when the number of potato-washing monkeys reached a critical mass — the “hundredth monkey” — the behavior suddenly and spontaneously appeared in monkey troops on other islands and on the mainland, with no possible physical contact between them.

This version is largely fiction. Watson himself later acknowledged: “It is a metaphor of my own making, based on very slim evidence and a great deal of hearsay.” The original researchers did not observe sudden, instantaneous transmission to other islands. Some monkeys on other islands did eventually learn to wash potatoes, but this could be explained by independent invention or by occasional inter-island contact.

Sheldrake, to his credit, has been clear about this. He does not use the hundredth monkey story as evidence for morphic resonance, precisely because the popular version has drifted so far from the actual observations. But he does point to the underlying phenomenon — the way new behaviors can spread through populations faster than individual social learning seems to allow — as worthy of serious investigation.

The Flynn Effect: Are IQ Tests Getting Easier?

A more robust piece of evidence comes from an unexpected source: IQ test scores. In the 1980s, political scientist James Flynn documented a startling trend. Average IQ test scores had been rising steadily in every country where long-term data existed — the United States, Japan, Britain, France, Germany, the Netherlands, and many others. The increases were substantial: roughly 3 points per decade, or about 15 points over the course of the 20th century.

This “Flynn effect” has been replicated extensively and is not in dispute. What is in dispute is why it occurs. Improved nutrition, better education, more familiarity with testing, reduced exposure to lead, and various other factors have been proposed. But none of them fully account for the pattern. Flynn himself described the effect as “baffling.”

Sheldrake offers a morphic resonance interpretation: IQ tests are getting easier because millions of people have already taken them. Each time someone solves a particular type of problem — a pattern recognition task, a spatial reasoning puzzle, a verbal analogy — they contribute to the morphic field of that task. Subsequent test-takers resonate with this accumulated experience and find the tasks marginally easier.

This is not the same as saying people are getting smarter. It is saying that specific tasks become easier for the human species as more individuals perform them — a prediction that morphic resonance makes and that standard biology does not.

Crossword Puzzles and Collective Learning

In his book Seven Experiments That Could Change the World (1994), Sheldrake proposed several do-it-yourself experiments that anyone could conduct to test morphic resonance. One of the most elegant involved crossword puzzles.

The prediction was simple: a crossword puzzle should be easier to solve after a large number of people have already solved it than before. If morphic resonance is real, then the solutions entered by millions of solvers should create a field that makes the answers marginally more accessible to subsequent solvers — even solvers who have no knowledge of the previously published solutions.

Preliminary tests with newspaper crosswords showed results consistent with this prediction, though the experimental controls were difficult to perfect. The challenge is separating morphic resonance effects from simpler explanations like increased familiarity with common crossword clue patterns.

What the Evidence Tells Us

None of these lines of evidence — the rat experiments, the crystal anomalies, the Flynn effect, the crossword results — constitutes proof of morphic resonance. Sheldrake himself frames morphic resonance as a hypothesis, not a proven theory. Each piece of evidence has alternative explanations, and mainstream science has not accepted the hypothesis.

But taken together, the evidence points to a pattern that is difficult to ignore: new behaviors and new forms tend to become easier to produce over time, in ways that are not fully explained by genetic inheritance, individual learning, or material communication. Something appears to be accumulating — some kind of memory or momentum — that makes repeated patterns increasingly probable.

Whether that something is a morphic field, an unknown physical mechanism, or simply a collection of conventional explanations we have not yet fully enumerated remains an open question. But the question itself is worth asking. Because if collective memory is real — if the experience of every organism that has ever lived is somehow accessible to every organism alive today — then we are not isolated individuals struggling alone in an indifferent universe.

We are nodes in a vast web of accumulated experience. Every skill you master, every insight you achieve, every challenge you overcome makes the same achievement fractionally more accessible to every other human being who will ever live.

If the rats at Melbourne were drawing on the experience of rats at Harvard without any physical connection between them, what might you be drawing on right now — and what might you be contributing — without knowing it?