Sorry, but copying text is forbidden on this website!
Previously in the UK, the use of the polygraph was dismissed by the British Government. Instead police officers use trained methods of detection and interrogation to find guilty people. However, recently the government approved compulsorily polygraph testing of paedophiles and sex offenders in pilot studies in 10 areas of the UK. This pilot polygraph study on sexual history disclosure testing (SHDT) was the first of its kind undertaken in Britain. This application of the polygraph was shown to be useful as a means of obtaining additional information about past sexual offending behaviours.
Fourteen sex offenders who were attending a ‘Community Sex Offender Groupwork Programme’ were given SHDTs. It was found that there was a significant increase in the number of admitted victims and offences when comparing polygraph disclosure results with previously obtained data from all other sources available. In addition, the subjects reported earlier onset of offending and a wider range of paraphilic interests than had previously been reported.
This suggested that collaboration amongst treatment, supervision and polygraph professionals could help to contain sexual offending behaviour more effectively, to improve and enhance public protection (Wilcox & Sosnowski, 2005). Although this does not show evidence for the accuracy of the polygraph, it points out potential other areas it may be used in. Furthermore, in the future perhaps the polygraphs may not be the leading machine in detecting deception. Studies now show that another machine-form of deception detection may be available for general use in the future.
Rather than using machines to measure signs of stress (which could be attributable to explanations other than lying), such as blood pressure and heart rate as polygraphs do, some of the new techniques actually look and the brain itself. These innovative procedures measure things such as brain waves and cerebral blood flow. This serves as an advantage to the polygraph, as people cannot control this activity in the brain. However, these procedures are not in too distant future, Brain Computer Interface (BCI) technologies have been around since the 1980s.
One technique by Farwell (1988) focuses on a specific electrical brain wave, called a P300, which is claimed to activate when a person sees a familiar object. The subject wears a headband of electrodes and faces a computer screen, which flashes images. The purpose of the device is to show if relevant images are recognised by the subject, they may have a deeper knowledge of it they did not reveal before. In a criminal situation, this would mean the person might have been involved with the item in question. Therefore, further interrogation may take place.
One example is showing a murder weapon or the victim. If the person previously denies knowledge of either then and they then fail the test this would seem to indicate they were lying. Farwell calls this procedure ‘brain fingerprinting’ and is keen for it to be used in US courts. This is an extremely useful tool, which could be used to coax witnesses into revealing more information and both eliminating and identifying suspects. It is currently available to the CIA and has been used successfully in a court case in the US. However, this deception detection technique is also not infallible.
It does not actually show that the person is lying; it only shows that they recognise the image. This could mean that they may have seen an item (murder weapon) but not have any conscious recollection of it. Furthermore, the National Research Council (2003) stated that due to the limited amount of study on accuracy, the use of the P300 in lie detection may have similar levels of accuracy to the polygraph. However, this is not the only brain scanning technique available at the moment. Work by Kosslyn et. al (2003) has shown that by using fMRIs specific areas of the brain activate when people are telling the truth or a lie.
Furthermore, the study suggests that different regions activate depending on the type of lie. Recently in the news, it was reported that Dr. Jennifer Vendemia has received a $5 million grant from the US defence department for research into monitoring brainwaves to detect lying. Vendemia states that this system could have accuracy between 94-100% (Summers, 2005). Therefore, it seems the future for lie detector machines looks promising. Overall, both the human and non-human measures of lie detection have their strength and weaknesses.
Although neither claims to be 100% accurate at present, both seem show signs of a future where lie detection is more accurate and less fallible. As seen in many areas of psychology, a collaboration of these techniques could be the most promising opportunity.
American Medical Association’s 23rd Annual Science Reporters Conference in Washington D. C. (2004). Retrieved 12 April 2005 from http://www. ama-assn. org/ama/pub/category/13161. html Barland, G. H. (1988). In A. Gale (Ed. ), The polygraph test. Lies, truth and science. London: Sage. 73-95.