Bullshit detection–or how Cameron uses the Kyle method
Most rational people agree that electronic equipment is really bad at detecting ghosts. EMF meters, ghost boxes and motion detectors are equally rubbish at detecting spirits, ghosts, souls or whatever you would call them. You wouldn’t expect the UK law enforcement agencies to use ghost boxes to try and ask a murdered man who his killer was. It would be stupid. Why? Because such equipment has not been proven to do what its proponents claim.
However, this doesn’t mean that law enforcement agencies aren’t subject to the same biases and fallibilities as optimistic ghost hunters.
Today the government has announced that polygraph testing is to be introduced across the UK for serious sex offenders on probation. This is problematic, as polygraph testing, despite being around for about 90 years, has not been proven and still exists in the realm of pseudoscience. Almost all psychologists agree that polygraph testing cannot be relied upon to identify if someone is telling the truth.
Despite this, the government wants to use the magic truth divining box – as seen on Jeremy Kyle to see if a chav has been lying to his girlfriend.
From the reports it seems that the test used by the probation service was little more than an elaborate wheeze to trick the offenders into coughing up the truth. The pilot programme results claimed that:
mandatory lie detector tests prompted sex offenders to:
• Be more honest with their offender managers. A No 10 source said they provided probation staff with more information about the potential risks they pose.
• Make twice as many disclosures to probation staff, such as admitting that they had contacted a victim.
• Admit the tests helped them manage their own behaviour more effectively.
The first two claims rely on several assumptions:
(a) the offenders believed the lie detector works;
(b) the offenders were completely truthful and not leaving out key information;
(c) the offenders were not able to game the test.
The third claim should have the bullshit claxon sounding off in any objective mind. Of course the offenders are going to claim the lie detector test worked if they think it would be favourable for them. There would be a self interested motivation for the offenders to tell their interviewers what they wanted to hear.
Polygraph tests rely heavily on the subjective judgement of the person conducting the test, by inference rather than intelligence. This appears to be little more than casting runes or reading tarot cards, except with the modern sparkle of electronics. Why not bring back phrenology to spot criminals?
Such a system might work, but it relies on the assumption that offenders don’t wise up to the truth: that polygraph tests are so fallible as to make them worthless. I can easily imagine offenders in prison training each other on passing these tests.
The government claims the pilot was a success (even the Guardian does), based on nothing more than what appears to be wishful thinking. That all adds up to a lot of bullshit.