Hysterical reaction & dangerous attempt by Tories to try & impose Pseudo-Science of “lie-detectors” on Scotland’s independent justice system - @HumzaYousaf is right to say no to the use of 'Jeremy Kyle' polygraph tests” - A thread on use of tests 1/22

John Larson invented the polygraph in 1921 as a medical student at the University of California, Berkeley and a police officer of the Berkeley Police Department in Berkeley, California

Larson was concerned that the polygraph never matured into anything beyond a “glorified stress-detector” & referred to it as “Frankenstein’s monster” also known as a “lie-detector” which he spent over 40 years combating after inventing it! -

Marston's another inventor said the inspiration for the device was his wife, Elizabeth Holloway Marston on the basis that 'When she got mad or excited, her blood pressure seemed to climb'"

What does it actually do? polygraph test measures changes in respiration,perspiration & heart rate. Sensors are strapped 2subject's fingers, arm & chest 2report on real-time reactions during interrogation. A spike on parameters indicates nervousness, & potentially points 2lying.

According to the American Psychological Association “Most psychologists agree that there is little evidence that polygraph tests can accurately detect lies."

What does it show then? A diagnosis of deception doesn’t necessarily mean that someone has actually lied. A polygraph test doesn’t actually detect deception directly; it only shows stress,

There's no unique physiological sign of deception. There’s no evidence whatsoever that things the polygraph measures-heart rate, blood pressure, sweating, & breathing — are linked to whether you're telling the truth or not- but don’t let the the Tories stand in the way of truth

Depending on whom you ask, the reliability of the test ranges from near-certainty to a coin toss. Despite claims of 90% validity by polygraph advocates, the National Research Council has found “no evidence of effectiveness”

What’s the problem? Many psychologists—& even police officers—contend that the test is biased toward finding liars & has a 50 percent chance of hitting a false-positive for honest people. - therefore if you are telling the truth you are likely to be penalised

In the 1998 US Supreme Court ruling on US v Scheffer it concluded “the risk of false positives is too high. ..there is simply no consensus that polygraph evidence is reliable” & ruled that passing the test cannot be seen as proof of innocence.

"Unlike other expert witnesses who testify about factual matters outside the jurors' knowledge, such as the analysis of fingerprints, ballistics, or DNA found at a crime scene, a polygraph expert can supply the jury only with another opinion."

The Supreme Court summarized their findings by stating that the use of polygraph was "little better than could be obtained by the toss of a coin!”

Imagine the scenario- a devious scheming terrorist who wants to beat the test has a 50% chance of doing so, walks free - goes on to murder innocent people in a bombing - what do the Tories & the Sun & the so called independent reviewer of Terror say then?

A polygraph test measures one thing: anxiety - surely that points to lying?
"All these physiological measures are simply associated with fear and anxiety,... people are anxious sometimes when they're telling the truth, and they can be not anxious sometimes when they're lying.

“The more practiced you are at lying,the less anxiety is associated with it." In other words, a polygraph test can sometimes be correct & sometimes be wrong- are we willing to risk lives on something that can get it so wrong ?

Polygraphs measure arousal, which can be affected by anxiety, anxiety disorders such as posttraumatic stress disorder (PTSD), nervousness, fear, confusion, hypoglycemia, psychosis, depression, substance induced states substance withdrawal state or other emotions;

Polygraphs do not measure "lies". A polygraph cannot differentiate anxiety caused by dishonesty and anxiety caused by something else.

The National Academy of Sciences (NAS) issued a report entitled "The Polygraph and Lie Detection". The NAS found that the majority of polygraph research was "unreliable, unscientific and biased"

UK Courts have never recognised the operators of such machines as properly qualified expert witnesses. This may well reflect concerns in the scientific community about the ‘pseudo-
science’ of polygraphy.

Historically, there has been an aversion to their use in the UK because of their perceived lack of reliability - they have been perceived not to work on psychopaths or sociopaths – adept at lying- what do the Tories think terrorists are?

On a final note on what the terror reviewer says - such tests are not allowed in our courts- so to conclude the Tories might want to destroy any semblance of Justice in England & Wales but they should keep their noses out of our independent & devolved system of justice