The UK has for many years resisted the introduction of the polygraph to its criminal justice processes. It was treated as too unreliable. Another example of American ‘exceptionalism’ alongside the electric chair and the Utah firing squads. Ok for the Americans, but not for us.
But now it’s arrived. Its introduction to the UK has been long drawn out and low key. The law permitting the use of polygraphs was passed as far back as 2007 (in the Offender Management Act) and even today not many people in the street would be able to tell you that it became available to the British police and probation officers from January 2014.
The polygraph is often described as a lie detector. Its use is based on the notion that lying induces a ‘stress response’ in the automatic nervous system, a part of the Central Nervous System that is largely outside conscious control and which regulates the body’s internal environment. The effect of this can be observed in changes in cardiovascular activity, breathing, and sweating. The basis of the polygraph examination involves individuals being asked a series of questions while activity in these systems is recorded, with certain reactions said to be indicative of deception.
President Richard Nixon, when considering polygraph tests for White House staff in 1971, famously declared:
and early 50 years ago the American academic Alan Westin declared:
Today a study by the American National Research Council is often taken as the bench mark for the reliability of the polygraph. Its 2003 report stated that polygraph accuracy stood at about 80-90%.
British Experiences of the Polygraph
The British have been quite hesitant about the polygraph. The British Psychological Society have produced two reports in 1986 and 2004 expressing their doubts. The latter concluded:
The 'stress response' which is measured, for example, may not be a response to 'deception' but could be prompted by surprise, cognitive load, loud noise, etc. The polygraph test is also said to be easily ‘beaten’ because if you bite the inside of your mouth or tongue on a question of no importance, unbeknown to the operator, he or she will begin to wonder - what’s the matter with this machine.
Having passed the enabling legislation in 2007 testing on sex offenders was piloted between April 2009 and October 2011 in the East and West Midlands’ probation regions. The study found that offenders who took the tests made twice as many disclosures to probation staff – for instance, admitting to contacting a victim or entering an exclusion zone, or thoughts that could suggest a higher risk of reoffending (Gannon et al 2014).
At the moment it will only be used on sex offenders –if the police use it they need the offender’s consent –probation can use it without their consent if it’s written into any parole conditions. The police say they will give extra attention to these who do not consent – not sure if that constitutes a free consent without duress being applied. No doubts the law will soon change to enable them to test without consent.
Alder K (2007) The Lie Detectors: the history of an American obsession, Simon and Shuster, New York
British Psychological Society (2004). A Review of the Current Scientific Status and Fields of Application of Polygraphic Deception Detection. Report (26/05/04) from the BPS Working Party (http://www.bps.org.uk).
Gannon T et al (2014) An evaluation of Mandatory polygraph testing for sexual offenders in the United Kingdom Sexual Abuse: a journal of Research and Treatment 26(2): 178-203
Westin A (1967) Privacy and Freedom, Bodley Head, London
Terry Thomas is emeritus Professor of Criminal Justice at Leeds Beckett University. His research areas include sexual offending and police information systems. His most recent book is ‘Domestic Violence and Criminal Justice’ written with Nicola Groves also from the Leeds Beckett University criminology group. He is currently working on the third edition of his book ‘Sex Crime: sex offending and society’ due out November 2015.