Piltdown Man Groupthink
Piltdown Man Groupthink
How nationalism, racism, and hype led to history's most famous scientific fraud
A few weeks ago, I told my 7-year-old son the story of the Piltdown Man hoax. I’m not sure how it came up, other than that it was part of our daily discussions about predatory dinosaurs, paper airplane designs, and Wimpy Kid books.
The look of fascination on his face as he learned about the most famous scientific fraud in history inspired me to dig up more details about the skullduggery involved.
As I started going through relevant sources, I soon realized that the Piltdown Hoax is not only a fascinating tale — but also an amazing parable about how easy it is to fall victim to groupthink.
We typically consider group decisions — especially when arrived at by experts — to be better than those made by the lone individual.
Yet although a correct decision may be the goal of an expert group, social psychologists find that this objective is seldom the primary factor influencing the judgments of the individual experts involved.
During debate, experts may feel reluctant to offend their colleagues by contradicting their views. Once a perceived consensus is established, some experts may also self-censor their doubts fearing professional reprisal.
Expert groupthink is most likely to occur when the conditions surrounding a decision remain uncertain, if most experts within a group share a strong commitment to a particular social identity, and if that identity is perceived as under threat.
The gravel pit and the skull fragment
In early 1912, the lawyer and amateur archeologist Charles Dawson sent a letter to his colleague Arthur Smith Woodward, head of geology at the prestigious British Museum in London. A workman a few years earlier had given Dawson a skull fragment from a nearby gravel pit in Piltdown, a hamlet in Sussex, England.
After consulting with fellow amateur archeologists, Dawson told Woodward that the skull fragment resembled the “Heidelberg Man”—Neanderthal remains unearthed a few years earlier in Germany.
If Pleistocene-era bones had been discovered at Piltdown, it would not surprise Woodward, since many geologists at the time believed that the gravel pit had been left behind by an Ice Age river bed.
After examining the skull fragment at the British Museum, the two men traveled to Piltdown to begin a systematic excavation.
By the end of the summer, Dawson and Woodward had recovered additional skull fragments, an ape-like jaw bone, flint tools, and what appeared to be Pleistocene-era mammal remains.
Before they could formally present the findings to their scientific peers — an unknown informant leaked news of the discovery to the Manchester Guardian.
“The Earliest Man? Remarkable Discovery in Sussex – A Skull ‘Millions of Years Old?,’” was the November 21, 1912 headline. The ape-man creature was “certainly from the beginning of the Pleistocene period,” and “there is no doubt of its authenticity.”
The cranium and jawbone were in fact the “earliest trace of mankind that has yet been found in England.” Compared to Germany’s famous Heidelberg Man, these fragments suggested “a much lower and more primitive type of mankind.”
The discovery, according to the newspaper, could settle a debate that had raged since Charles Darwin’s 1850 publication of The Origin of Species. The “theory of evolution applied to man suggest[sic] that he had a common origin with the apes.” Yet to satisfy Darwin’s skeptics, the “need has been felt for discovering ‘the missing link’ between the highest apes and the lowest men’.”
In 1891, on the island of Java in South Asia, the Dutchman Eugène Dubois had discovered fossilized remains of a small partial cranium, teeth, and a modern-looking femur indicative of an upright posture.
Dubois named the species Pithecanthropus erectus (erect ape-man), claiming it was a “missing link.” Yet many geologists doubted the claim.
Over the next few years, Neanderthal remains like Heidelberg Man were recovered from multiple sites in Germany. In contrast to their European rivals, British scientists had yet to find pre-human remains in their own country.
But now according to The Manchester Guardian “there appears to be no doubt of whatever of its genuineness…[and] more than a possibility of its being the oldest remnant of a human frame yet discovered on this planet.
Selling the discovery
The Geological Society of London held a special December 1912 meeting so that Woodward and Dawson could formally present their findings. Using lantern slides and diagrams, they argued that the bone fragments represented an ape-man from the early Pleistocene period, possibly the oldest such remains found in the world.
“The skull may be regarded as presenting a hitherto unknown species of homo, for which a new name is proposed," Woodward said. They named the species Eoanthropus Dawsoni – “The Dawn Man.”
In convincing many in attendance that day, Dawson and Woodward likely benefited from the advance publicity. The Manchester Guardian had spun a vision of an early Pleistocene ape-man that resonated not only with British nationalism but with the iconic quest to locate the “missing link.”
The newspaper’s vivid account went well beyond the more cautious, tentative style of arguments that Woodward could present to his peers.
Imagine for a moment that you are a British scientist in November 1912 picking up the Manchester Guardian that day—or reading a clip a few days later that had been sent to you in the mail.
The storm clouds of World War I are on the horizon, as a belligerent Germany pursues a policy of militarization. The British Empire is in decline. America is passing Britain as the world leader in science and technology.
Yet if the Manchester Guardian’s report proved true, Britain had just catapulted back to the top of the international order.
A news story about Dawson and Woodward’s presentation at the Geological Society only helped bolster their case. “The Earliest Skull. ‘A Hitherto Unknown Species.’ Story of the Sussex Discovery,” was the headline at the Manchester Guardian.
The production of scientific knowledge and popular communication about that knowledge are conventionally considered distinct activities. First comes the research, peer-review, and scientific article—and only then does popular communication begin.
Each discipline differs, but every discipline as part of the peer-review process follows particular rules for gathering, analyzing, and interpreting evidence, and the standards by which a claim must be assessed.
Very few topics in science are completely "settled" or certain. Scientific theories, findings, and knowledge are instead considered provisional, open to challenge and revision.
But similar norms of rigor and scrutiny are not usually applied by journalists writing for the popular press, or by editors publishing commentaries by scientists. This provides scientists with the opportunity to go beyond what can be said in a journal article and to use the popular press as a forum to promote their research — not only to the public but also to their scientific peers.
Over the centuries, these strategies have varied in form – but they reveal how scientific knowledge is constantly being shaped, interpreted, and promoted outside of formal peer-reviewed channels.
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Yet even with the aid of publicity, some at the December 1912 presentation voiced their reservations about linking the skull and the jawbone to the same individual – since they were so anatomically different.
These critics did not question the fragments’ Pleistocene era origins, but rather believed that the skull represented a more human-like individual from the period and the jawbone a different, more ape-like one.
Woodward admitted the incongruence, but countered that the accumulation of evidence suggested a single individual. The fragments were found in the same pit, the same layer of sediment, and adjacent to each other.
Silencing skeptics
Woodward and Dawson followed their 1912 presentation by publishing a series of papers in the the official journal of the Geological Society.
But as news spread outside of Britain, foreign scientists voiced their skepticism about the authenticity of the alleged “missing link.” When requests to directly examine the fragments were denied, the decision deepened their suspicions.
In 1915, “Piltdown Man II” was discovered a few miles away from the original pit. The fossil fragments included a human-like cranium and ape-like tooth with wear marks unlike any modern ape.
The emergence of a second Piltdown Man silenced skeptics among foreign scientists. Based on gathered evidence, scholars also believe that there were scientists working within the British Museum who had quietly uncovered the fraud — but did not step forward for fear of disturbing the canonical peace.
The unwillingness of skeptics and museum insiders to speak out was likely also driven by the credulous headlines about Piltdown Man that had been running in newspapers across the world.
In many of these stories, their scientific peers were quoted, affirming the ground-breaking nature of the discoveries. In other cases, scientist enthusiasts published popular articles that extolled the genuineness of an English ape-man missing link.
In arguing on behalf of Piltdown Man's authenticity, these scientists could bypass the stricter standards for evidence required by science journals. But at the same, they drew on their scientific authority to spin culturally persuasive narratives about Piltdown Man’s "humanness.”
But given its chimeric ape-human qualities, why would Piltdown Man be declared the "Earliest Englishman" by scientists and journalists?
The narrative was not scientifically based, but fit a vernacular "folk wisdom" of the British Empire-era that traded on themes of nationalism and racism.
Piltdown Man’s hybrid "almost humanness" was rationalized by often linking the remains more closely to indigenous and non-white peoples — "savages" according to the racist vernacular of the day.
In this way the "Earliest Englishman was moved closer to us, whilst non-white, non-Europeans were moved further away," writes sociologist Murray Goulden.
Yet over the next few decades as more human-ape remains were found in South Africa, Java, and China, each were anatomically opposite to Piltdown Man. Their skulls were more ape-like and their jaw bones more human-like.
These subsequent findings appeared to form a consistent evolutionary tree (but only if Piltdown Man were excluded from consideration).
Piltdown Man supporters, however, could still reason away the mounting discrepancies by claiming that their favored bones were much older – thereby representing a separate, uniquely English man-ape species.
In 1953, Kenneth Oakley of the British Museum and J.S. Weiner of the University of Oxford published a study with colleagues that re-examined the Piltdown fragments. They relied on advanced stereomicroscope technology, a new fossil dating method, and other innovative techniques.
Their tests placed the skull as no older than 50,000 years, rendering Piltdown Man an “evolutionary absurdity,” with no known ancestor or descendant, they wrote.
According to Oakley and Weiner, a “modern ape jaw had been deliberately placed with the more ancient brain-case, and that to disguise its modern character and link it with the human brain-case, the bone had been suitably stained, and the teeth deliberately ground down.”
In a 1954 commentary at Science magazine, the American anthropologist William Strauss attempted to explain why it had taken forty years to unmask Piltdown Man as a forgery.
In assigning blame, Straus conveniently ignored the role of scientific nationalism, racism, and hype in promoting expert groupthink. Instead, he argued that until Oakley and Weiner’s tests had revealed the modern origins of the bones, there was no reason to suspect fraud. And those tests had only become available in recent years.
The status seeking con man
Over sixty years later, a team of anthropologists led by Isabelle de Groote published a 2016 study describing their investigation of the Piltdown bone fragments using DNA analyses, CT scanning, and X-ray tomography.
They concluded the jawbone fragments for both Piltdown I and II came from a single Borneo orangutan, and the skull fragments from two or three possibly medieval humans.
The bones and teeth had been cleverly loaded with gravel held in place with pebble plugs; making them feel heavier, and therefore more fossil-like. Silicate dental putty was used to reconstruct the fragments, and piece them together where needed.
Since the 1950s, at least twenty individuals have been suspected of involvement in the hoax. But consistent with the conclusions of several book-length studies, de Groote and her colleagues concluded that Dawson was the lone perpetrator.
Dawson was the origin of the original fragment – and either found the rest of the fragments, or was present when they were discovered. The consistency in method for how the flints and bones were chiseled and manipulated also suggest that a lone person did the work.
He had the connections and means to obtain the skull, jawbone fragments, mammal fossils, and tools that he stained and manipulated. He likely knew who to talk to at the newspapers, and was acquaintances with Woodward – head of geology at the prestigious British Museum.
As a lawyer, Dawson had swindled his associates in various real estate deals, and the majority of his other archeological finds were eventually discovered to be frauds. Notably following his death in 1916, no remains similar to those of Piltdown Man were ever again recovered.
To pull off a scientific fraud, you have to give scientists and the public what they are looking for. Dawson as an experienced fossil hunter knew that the British scientific community was searching for its own “missing link.”
He would have known that scientists were looking for stained bones suggesting the Pleistocene age of the skull and jaw. He also knew that in order to corroborate the Piltdown Man fragments, adjacent tools and mammal fossils needed to be recovered.
But why would Dawson commit such a crime? In 1909, when Dawson claimed the first Piltdown fragment had been handed to him by a worker, he was 44 years old. By then he had authored or co-authored some 50 publications in geology, archeology, and history, explains de Groote.
As a prolific amateur, Dawson likely felt he had never gained the recognition from the scientific establishment he thought he deserved. In a 1909 letter to Woodward, he lamented “waiting for the big ‘find’ which never seems to come along….” Later that year his younger naval officer brother received a knighthood.
Dawson’s wife soon wrote to the British Home Secretary, who she refers to as an “old friend,” suggesting that because of his quarter century of scientific service, her husband also deserved recognition.
Before Dawson died in 1916, he was nominated for induction into the Royal Society (Britain’s highest scientific honor), but the nomination was rejected.