And so, five international experts were put to the test covertly, re-examining matched prints from their own old cases while armed with different — and potentially biasing — "case information." They'd agreed to be tested, but they didn't know when — or even if — test prints would cross their desks.
That night in Brighton, the results were in. For Charlton, they were a jaw-dropper.
"Not only some, but most, of the fingerprint examiners changed their minds," said Dror, who was far less surprised by the flip-flopping. As an expert in human thought processes and the hidden power of cognitive bias — an array of distortions in the way humans perceive reality — he had a decided advantage.
Fingerprints have been accepted as unassailable evidence in courts for more than 100 years, but vaunted claims of their uniqueness and infallibility still lack scientific validation. By contrast, the existence of cognitive bias and the subjective nature of human judgment have been thoroughly established by hundreds of scientific studies going back decades.
Dror knew the ways in which unconscious bias could impact expert decision-making, yet allowances were rarely made for it in the work of fingerprint or other forensic examiners. Then, in February, a landmark National Academy of Sciences report on forensic science called for massive reform. The report, which cited Dror's studies, sent a strong message about the need for research into the effects of cognitive bias and finding ways to minimize it.
The article describing the study and its aftermath, here, is worth a look if you have a fingerprint case where you are looking to challenge either the finding or the fingerprint's use in court.