Can lie detectors be trusted?

Detailed commentary from Patrick Barkham in the Guardian (18 Sept), exploring the use of ‘lie detecting’ machines in the UK. He covers the use of voice stress analysis in benefit offices and insurance companies, and polygraphy for sex offenders. Interesting stuff, and well worth reading in full over on the Guardian site. Here’s a flavour:

[Harrow] council prefers the phrase “voice risk analysis” and Capita calls its combination of software, special scripts and training for handlers the “Advanced Validation Solution”. Just don’t say it’s a lie detector. “Please don’t call it that. We’re not happy with that. It’s an assessment,” says Fabio Esposito, Harrow’s assistant benefit manager.

… Voice stress analysis systems have been used for more than five years in the British insurance industry but have yet to really catch on, according to the Association of British Insurers. There was an initial flurry of publicity when motor insurance companies introduced the technology in 2001 but it is still “the exception rather than the norm,” says Malcolm Tarling of the ABI. “Not many companies use it and those that do use it in very controlled circumstances. They never use the results of a voice risk analysis alone because the technology is not infallible.”

… Next year, in a pilot study, the government will introduce a mandatory polygraph for convicted sex offenders in three regions. … Professor Don Grubin, a forensic psychiatrist at Newcastle University… admits he was initially sceptical but argues that polygraphs are a useful tool. “We were less concerned about accuracy per se than with the disclosures and the changes in behaviour it encourages these guys to make,” he says. “It should not be seen as a lie detector but as a truth facilitator. What you find is you get markedly increased disclosures. You don’t get the full story but you get more than you had.”

…critics argue that most kinds of lie-detector studies are lab tests, which can never replicate the high stakes of real lies and tend to test technology on healthy individuals (usually students) of above-average intelligence. Children, criminals, the psychotic, the stupid and even those not speaking in their first language (a common issue with benefit claimants) are rarely involved in studies.

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