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30-Jun-2022
Alan Turing - genius and forensic pioneer
Note: In celebration of Pride Month, our June newsletter starts with Alan Turing. This story is an abridged version of Dr. Mark Perlin's DNA Matters column on What Forensics Owes to Alan Turing published this month in "Forensic Magazine".
British mathematician Alan Turing was born in June of 1912. Esteemed as the father of Computer Science, his Turing Machine revealed the full power of modern computation, while his Turing Proof showed its limits.
As portrayed by Benedict Cumberbatch in "The Imitation Game" movie, Turing's decrypting the German Enigma device helped the Allies win World War II. The British government prosecuted him in 1952 for homosexual acts, inflicting forced chemical castration. Two years later, in June of 1954, Turing took his own life at age 41.
Turing also laid the foundation for modern Forensic Science. In cracking the Nazi's Enigma code, he introduced the likelihood ratio (LR) to measure digital information. The LR shows how much the support for a hypothesis is changed by an experiment. The LR is routinely used to measure identification information in DNA and other forensic evidence.
Advanced computer systems, like Cybergenetics' pioneering TrueAllele® technology, accurately assess the impact of new evidence. Examining data, the computer measures the change in the chance that someone left their DNA. The reported LR number – Turing's Statistic – can help find, convict, acquit or exonerate suspects.
In 2009, the British Prime Minister apologized for Turing's mistreatment. In 2013, the Queen pardoned the persecuted genius. In 2017, the Turing Law retroactively pardoned men for committing homosexual acts under past legislation.
Every year, an outstanding computer scientist receives the Turing Award – that field's Nobel Prize equivalent. And, every year, crime labs choose to not use Turing's effective LR methods. They mismeasure inaccurate information on millions of DNA items. Vital evidence is lost to criminal justice.
Turing was an Artificial Intelligence pioneer. In the "imitation game" he devised, a machine would pass the Turing Test when its behavior closely resembled a person's. But in Forensic Science, the AI situation is reversed. Smart computers now reliably measure information on complex DNA samples. Yet only on simple DNA can a human hope to pass the Turing Test.
The world needs a new Turing Law, one that pardons mistreated DNA. When data have been ignored, or LR values are wrong, justice should demand a second look at failed DNA evidence.