The polygraph machine – or ‘lie detector’ – has long been tied-up with sex and sexuality, from the use of the device to out homosexuals during McCarthyist witch-hunts to the recent use of polygraphs to monitor convicted sex offenders. Reports of the success of this programme warrant scepticism and careful analysis, not least because the machine doesn’t detect lies, but also because the history of polygraphy tells us that it is a slippery slope from using it in one area to its spread into all realms of social life.
The majority of psychologists will tell you that the polygraph machine does not work – and they are right. It doesn’t detect lies. Nonetheless, in the past century the machine has been used in a variety of situations in the United States, including for job applicant screening, police investigations, in agreeing divorce settlements, or for resolving family and business disputes. Its proponents have sold it more on a political promise than on scientific credentials, as a tool in the fight against crime, to challenge police corruption or to combat terrorism. Sex offenders are just the most recent group to play a role in these scientific and political fictions.
In the UK we have thus far been more circumspect regarding lie detection, and thanks to this scepticism the polygraph does not have the kind of mythic quality that it seems to engender in American hearts. However, there are a few areas in which examinations have crept in, chief amongst them being their use to monitor sex offenders post-probation. After changes to the Offender Management Act in 2007, trials were run and eventually polygraphy was rolled-out across the UK. It is now reported that through these routine examinations 63 of 492 convicted sex offenders have been returned to prison after they admitted to breaches of their probation conditions.