Forensic Experts and Hubris

Testifying forensic experts have to have a touch of cognitive hubris. It's a job requirement. Too much of it though can lead to overstated findings, and when topped with esteemed expert credentials, to "Spilsburyisms."

The recent admission by the U.S. Justice Department of flawed FBI forensics reports from examiners in its laboratory's microscopic hair comparison unit has again raised questions on the weight given to the conclusions of forensic experts in disciplines lacking rigorous research supporting their methodologies, whether it be the analysis of hair samples or defective air bags.

The DOJ is now reviewing thousands of criminal cases in which faulty science per se was less of an issue than the FBI experts consistent exaggeration of the reliability of their findings. Given the credentials of the experts in what has been called the FBI laboratory's “elite unit,” the impact on many court decisions appears to have been substantial. This combination of dubious science and esteemed experts believing in the exactitude of their own conclusions , of "Spislburyisms", has a long history in the courts. 

The eponymous pathologist, Sir Bernard Spilsbury, was the pre-eminent expert in his field in 1920s England working with what would be called Scotland Yard, at a time when forensic science was establishing itself in the courts on both sides of the Atlantic.

In one of the most celebrated murder trails of the time, Spilsbury found clear signs of extensive physical trauma resulting from the violent death of Elsie Cameron, the fiancee of Norman Thorne, a chicken farmer who was accused of the murder. Two pathologists for the defense disagreed with Spilsbury's findings.

Although experts in the FBI hair microscopy lab have been referred to as elite, they could not receive the level of esteem bestowed on Spilsbury. The judge in Thorne's trial, Mr Justice Finlay, repeatedly referred to Spilsbury as an ‘eminent pathologist' while making no comment on the qualifications of the defence pathologists.

The facts in the Thorne case hinged on the forensic evidence, as is often the case in trials requiring experts from the FBI laboratory today or other forensic scientists.

Thorne initially claimed that his fiancee Cameron never arrived at his farm. When the police found her dismembered body under his chicken run, he changed his story and claimed that he and Cameron had had an intense argument in which she falsely claimed to be pregnant. He left to cool off and when he returned, he found that she had hung herself, although her feet were touching the floor. He cut her down. Believing that he would be held responsible if he did not conceal the body, he claimed that, in a moment of “frenzied madness,” he dismembered her body and buried it.

Sir Spilsbury found no bruising around the neck to suggest she had hung herself, as well as finding no torn skin, broken bones or bruising of the skin. Spilsbury did, however, find bruising under the skin, or “pulped tissue” that he concluded was the result of violence, supporting the prosecution's theory that Thorne had beaten her to death with something like an Indian club.

The two defense pathologists came to different conclusions than Spilsbury, although they did conduct their autopsy much later, after the body had significantly decomposed. While hubris may continue to be an issue in forensics, at least today evidence can be preserved far better than a hundred years ago.

One of the defense pathologists, Dr. Robert Matthew Brontë, explained that the victim's bones were thinner than average and that her head would have shattered “like egg shell”¹ if she had been hit by an Indian club as suggested. Brontë said that the tissue samples he had taken supported his conclusion that the bruising found by Spilsbury was relatively minor, and his samples of Cameron's neck showed microscopic signs of partial hanging, of Cameron suffocating slowly and actually dying after she had been cut down. The other defense pathologist, Dr Hugh Miller Galt, disagreed also with Spilsbury's finding of “pulped tissue”, arguing that in his experience such tissue would only be found with broken bones. The bruising that Spilsbury saw could have been much less severe, caused by Cameron falling to the floor as she was cut down.

Justice Finlay instructed the jury that the tissue evidence was of decisive importance and did note that the complex positions taken by the pathologists left them with a difficult decision.

The jury deliberated less than half an hour before convicting Thorne.
Before being executed,Thorne wrote, “I am a martyr to Spilsburyism.”²

While doubts of Thorne's guilt swirled in the press at the time, and even Arthur Conan Doyle wrote of his misgivings,³ an appeal of Thorne's case was denied and Sir Spilsbury continued to seal the fate of many suspected murderers, conducting more than 20,000 autopsies over his career.⁴

The most recent of Spilsburyisms, that of FBI lab examiners potential exaggeration of the reliability of their findings in over 3,000 cases spanning a 20 year period, shows how persuasive the belief  in "scientific evidence" continues to be in the court room. No one knows whether Thorne was innocent, nor if Spilsubury ever sent an innocent man to the gallows, nor if the faulty FBI evidence alone ever convicted an innocent person. But the odds seem strongly in favor of it.

In the ongoing review of cases involving the FBI examiners,  erroneous statements were made in 96% of the cases (out of the 268 trials reviewed  to date). Of these cases, 32 defendants were sentenced to death, and of those, 14 have been executed or died in prison, according to the Innocence Project, which is working with the National Association of Criminal Defense Lawyers (NACDL) and the Justice Department in the review.⁵

Forensic standards have improved since Spilsbury, but not overwhelmingly so. In 2009, the U.S. National Research Council (NRC) report on forensic science found that "… some forensic disciplines are supported by little rigorous systematic research to validate the discipline's basic premises and techniques."⁶

The FBI recently acknowledged that until 2012, hair examiners "… lacked written standards defining scientifically appropriate and erroneous ways to explain results in court”, according to a Washington Post report. ⁷ Yet the FBI acknowledged in 1984 that visual comparisons could not positively determine that a hair found at a crime scene belonged to one particular person. Going back further, in 1997 an investigation of the FBI Lab by then DOJ Inspector General Michael R. Bromwich found systemic problems, and noted the lab's lack of written protocols and examiners' weak scientific qualifications.⁸

When the 2009 National Research Council (NRC) report on forensic science was published, the National Academy of Science noted that strong standards and protocols for analyzing and reporting on evidence was lacking. It urged congress to create a National Institute of Forensic Science to “… establish and enforce standards for forensic science.” Although the NRC report was congressionally mandated, nothing has materialized from the report's recommendations in the years that have followed. Several congressman have recently issued press releases expressing how “deeply troubling” the recent FBI forensic exaggerations have been, and their intent to “… improve the science and standards.”⁹

Some of the more jaded voices in criminal defense doubt how soon improvements will come. There are arguments that the most important trait to be an effective forensic expert witness is not adherence to rigorous standards and protocols based on scientific research, but the ability to be persuasive — in other words, hubris.

Sir Bernard Spilsbury did the best with the science available at the time, just as most forensic experts today. While the reports, reviews, press releases and new stories comment on the failures of the forensic experts,  those who have failed to challenge the science of these experts and those who were easily persuaded by them have certainly contributed to the failures of justice.

It seems their may still be more martyrs to Spilsburyism.