40-hour experts

One of the ongoing themes in Thingfinder is the concept of cognitive pollution - the belief in an idea which is demonstrably wrong or which cannot be proven to be true. There is much more of it about than there should be two or three hundred some years on from the dawning of the Age of Enlightenment.

Here is another example. From How a Dubious Forensic Science Spread Like a Virus by Leora Smith. She doesn't quite make the case that blood spatter forensics is completely wrong but she makes a compelling case that it is consequential and yet unproven.

Read the whole article for how an untested and unverified technique has not been adopted through out the United States despite never having been validated.

In 2013, Attinger published his first blood-spatter paper in the journal Forensic Science International. One of his three co-authors was a now-retired Canadian police officer who had been an assistant teacher in MacDonell’s workshop.

The paper showed that the hypotheses that underpin bloodstain-pattern analysis remained largely untested. And, it said, analysts’ assumptions and errors could make their conclusions rife with uncertainty. Analysts failed to properly account for gravity when using bloodstains to calculate victims’ locations. They assumed things about how speed influences blood patterns that had never been scientifically proven.

[snip]

A review of Attinger’s research reveals some investigation of fundamental questions, like trajectories of blood in flight. But his experiments are highly simplified and extremely specific when compared with the complex problems faced at crime scenes. “The key in doing meaningful experiments,” he said, “is to start from the simple, understand it and then go to the complex.” A recent paper, for example, examined distortions of bloodstains on perfectly flat-lying military fabrics, results that Attinger and his co-authors said could be generalized to any woven fabric that had been laundered four or more times.

Such studies frustrate forensic experts like Ralph Ristenbatt, an instructor of forensic science at Pennsylvania State University and 15-year veteran of the Office of Chief Medical Examiner in New York City. “These are great academic studies,” he said, “but what do they lend to real-world problems?” Ristenbatt said he isn’t sure researchers will ever be able to model lab experiments as complex as real life, so they may not be the best way to address the chasm between analysts’ training and the conclusions they draw at crime scenes.

“There’s this belief out there that you can look at the patterns of blood at a crime scene and it’s the be-all end-all,” he said, “when in reality bloodstain-pattern analysis is just one tool in the toolbox of what we call crime-scene reconstruction.” The very idea that bloodstains will “tell the story for us,” he said, is “misguided.”

Innocent people are likely being convicted of crimes they did not commit owing to what comes down to an appeal to authority over a scientific technique which has been widely accepted and never proven.

Text book cognitive pollution.

This is not dissimilar to an account in The New Yorker nine years ago; Trial by Fire, Did Texas execute an innocent man? by David Grann.

ne day in January, 2004, Dr. Gerald Hurst, an acclaimed scientist and fire investigator, received a file describing all the evidence of arson gathered in Willingham’s case. Gilbert had come across Hurst’s name and, along with one of Willingham’s relatives, had contacted him, seeking his help. After their pleas, Hurst had agreed to look at the case pro bono, and Reaves, Willingham’s lawyer, had sent him the relevant documents, in the hope that there were grounds for clemency.

Hurst opened the file in the basement of his house in Austin, which served as a laboratory and an office, and was cluttered with microscopes and diagrams of half-finished experiments. Hurst was nearly six and half feet tall, though his stooped shoulders made him seem considerably shorter, and he had a gaunt face that was partly shrouded by long gray hair. He was wearing his customary outfit: black shoes, black socks, a black T-shirt, and loose-fitting black pants supported by black suspenders. In his mouth was a wad of chewing tobacco.

A child prodigy who was raised by a sharecropper during the Great Depression, Hurst used to prowl junk yards, collecting magnets and copper wires in order to build radios and other contraptions. In the early sixties, he received a Ph.D. in chemistry from Cambridge University, where he started to experiment with fluorine and other explosive chemicals, and once detonated his lab. Later, he worked as the chief scientist on secret weapons programs for several American companies, designing rockets and deadly fire bombs—or what he calls “god-awful things.” He helped patent what has been described, with only slight exaggeration, as “the world’s most powerful nonnuclear explosive”: an Astrolite bomb. He experimented with toxins so lethal that a fraction of a drop would rot human flesh, and in his laboratory he often had to wear a pressurized moon suit; despite such precautions, exposure to chemicals likely caused his liver to fail, and in 1994 he required a transplant. Working on what he calls “the dark side of arson,” he retrofitted napalm bombs with Astrolite, and developed ways for covert operatives in Vietnam to create bombs from local materials, such as chicken manure and sugar. He also perfected a method for making an exploding T-shirt by nitrating its fibres.

His conscience eventually began pricking him. “One day, you wonder, What the hell am I doing?” he recalls. He left the defense industry, and went on to invent the Mylar balloon, an improved version of Liquid Paper, and Kinepak, a kind of explosive that reduces the risk of accidental detonation. Because of his extraordinary knowledge of fire and explosives, companies in civil litigation frequently sought his help in determining the cause of a blaze. By the nineties, Hurst had begun devoting significant time to criminal-arson cases, and, as he was exposed to the methods of local and state fire investigators, he was shocked by what he saw.

Many arson investigators, it turned out, had only a high-school education. In most states, in order to be certified, investigators had to take a forty-hour course on fire investigation, and pass a written exam. Often, the bulk of an investigator’s training came on the job, learning from “old-timers” in the field, who passed down a body of wisdom about the telltale signs of arson, even though a study in 1977 warned that there was nothing in “the scientific literature to substantiate their validity.”

Another instance where an appealing technique is adopted lock-stock-and-barrel without rigorous testing.

If blood spatter is an unverified technique and arson investigation uses unverified techniques and all the very smart lawyers and judges find that acceptable, what does that say about our system of "experts"? And just how often are rules of thumb and professional prejudices being passed off as science? Way more often than we should expect.