UK police increasingly using polygraph tests

Polygraphs are based on principles beyond junk science. Any person who has been in a cult organization and has successfully exited can testify to convincing yourself something happened or is true even if the evidence is overwhelmingly the opposite, even under a polygraph. People are not reliable sources of fact, period. They are an interrogation technique based on scare tactic strategy to get people to confess to something regardless of if it is true or not.

Polygraphs only do one thing, enable lazy investigation into claims of fact. That's why police love them so much.

> The Home Office says the polygraph records physiological changes in a person, quoting research from the American Polygraph Association which found deception is accurately detected in 80 to 90% of cases.

80% accuracy is a bold claim. Here's Wikipedia [1]:

Despite claims that polygraph tests are between 80% and 90% accurate by advocates,[21][22] the National Research Council has found no evidence of effectiveness.[14][23] In particular, studies have indicated that the relevant–irrelevant questioning technique is not ideal, as many innocent subjects exert a heightened physiological reaction to the crime-relevant questions.[24] The American Psychological Association states "Most psychologists agree that there is little evidence that polygraph tests can accurately detect lies."[8]

I'm not really convinced by the 80%.

> Since 2014, probation services have carried out more than 8,800 polygraph tests, while police have conducted more than 4,600, says Prof Grubin, who explains around 60 to 70% result in disclosures - where someone reveals relevant information.

"Reveals relevant information" doesn't mean "was confirmed to have lied about whether they did the crime". Being questioned is stressful, stressed suspects' memories are unreliable even if the police never try anything malicious, and police sometimes do try malicious "techniques". One example is memory implantation [2]. To use the hypothetical example that Professor James Duane gave in the Don't Talk to the Police [3] lecture, suppose that a suspect previously heard a news report of a murder: "Three victims were killed." No mention of a murder method. During interrogation, the police officer asks, "How many people were shot to death?" The suspect falsely remembers that the news report mentioned a shooting.

[1] https://en.wikipedia.org/wiki/Polygraph

[2] https://en.wikipedia.org/wiki/Memory_implantation

[3] https://www.youtube.com/watch?v=d-7o9xYp7eE

When you dismiss your own rationality to defer to “experts”.