However, at present it seems that these people are so few, that human lie detection, as an accurate source of lie detection, is still a few years ahead. Perhaps non-human alternatives that are already in place should be looked at for the future of lie detection. In the United States, the police services often use a lie detector called a polygraph.
It often assumed that lying is accompanied by a change in the body’s physiological activity (Bull, 1988). According to Raskin (1988), ‘the polygraph is a means of detecting biological traces of an event which is stored in the brain or a perpetrator or witness’ (p78). The polygraph is used by law enforcement agencies in the U.S., the U.S. government and the private sector (e.g. to see if a partner is being faithful or not). It was developed by Leonarde Keeler in the 1930s to late ’40s. The device measures cardiovascular activity, elector dermal activity and respiratory activity. The responses are recorded on a paper/needle trace and a trained expert analyses the readings. The expert asks the subject a few control questions and then questions that the subject will have to respond with a ‘yes’ or ‘no’ to. The expert compares patterns with those when the subject was definitely telling the truth.
The expert looks for a number of things when detecting a lie. Firstly, it is expected that there will be an increase in breathing rate and heart rate. The cardiovascular responses are measured through a cuff on the arm which measures heart rate and BP. When these increase it is thought that the subject is under stress and is lying. In addition, galvanic skin responses and breathing rates are monitored for changes that alert the examiner to stress (lying). The standard method in police situation is to administer a Controlled Question Test (CQT). This is a comparison method where the control question is a neutral or non-threatening question. This is followed by a relevant question and the comparisons are monitored. The use of the polygraph is common in the US; accuracy is generally thought to range from 85 to 90 per cent (Raskin, 1988). However there are many problems with the system studies show it is not infallible.
Firstly, it has been found by many studies that although the CQT is fairly accurate at detecting deception it cannot detect truthfulness in an innocent person better than chance (Kleinmuntz & Szucho, 1984b). This suggests that the odds may be stacked again the innocent person. Additionally there may problems with the people who actually analyse the information. An earlier study by Szucho and Kleinmuntz (1981) showed that the best interpreter classified 18% of truthful subjects as untruthful. The worst interpreter incorrectly classified 55% of truthful subjects as untruthful. This has serious implications as it provides further evidence that innocent people may be convicted of crimes they did not commit. Research has shown that the rate of false positive scores is consistently higher than of false negative results and overall accuracy of the polygraph falls to 80-90% at best. Additionally, according to Faigman, Fienberg and Stern (2003), over-confidence in polygraph accuracy may lead to jurors believing it as scientific fact if admitted as evidence. Fortunately the US courts do not have to allow polygraph results to be admitted as evidence. However one occasion when it was admitted showed a further problem with this deception detector.
A convicted criminal called Floyd ‘Buzz’ Fay was wrongly convicted using the polygraph on the basis of a failed polygraph and subsequently trained fellow inmates to cheat the tool. After only 20 minutes of instruction, 23 of the 27 inmates were successful in defeating the polygraph examination (Ford, 1995; Kleinmuntz & Szucko, 1984). These ‘countermeasures’ present a real problem in that when someone is trained the device becomes useless. Although some polygraphers claim to know about these countermeasures and compensate for them, a study conducted by Honts, Rakin and Kircher (1994), revealed that 50% of the subjects trained to fool an examiner succeeded. Therefore although the polygraph can elicit detection of deception, on it’s own it is not infallible.
Additionally, the base rate for deception may also affect the accuracy of the polygraph. This refers to the fact that the polygraph assumes that there is at least some people who are guilty (e.g. 1 in 1000). This means that some people may be falsely accused, as it is assumed someone is guilty. Furthermore, the environmental stress that the procedure elicits on the subject may evoke a natural response of stress rather than the occurrence of lying. In one such instance in 1982, a man who was expected to be executed the following day was given a polygraph test. Roger Coleman maintained his innocence when he asked for a polygraph test; the state claimed that he failed it. However there was strong evidence to suggest that he was innocent.
The polygraph is most effective when it is assumed to work and the subject confesses. However as reported in a recent review of polygraph deception detection (Bull et. al, 2004), the problem with confessions is that they are not independent from polygraph scores. In other words when the subject has already confessed the administering of a polygraph will obviously show that they are not lying because they have already admitted to the crime. This leads to a higher accuracy rating of the polygraph than is perhaps realistic. Although the polygraph is useful in gaining confessions from people who are genuinely guilty, the accuracy issues seem to suggest that perhaps it should not be used strictly for finding who is guilty of crimes.
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.
References
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.
Bull, R. (1988). What is the lie-detection test? In A. Gale (Ed.), The polygraph test: Lies, truth and science. (p10–18). London: Sage.
Bull, R., Baron, H., Gudjonsson, G., Hampson, S., Rippon, G., & Vrij, A. (2004). A review of the current scientific status of field of application polygraph deception detection. Retrieved 12 April 2005 from .
DePaulo, B.M., and W.L. Morris. In press. Discerning lies from truths: Behavioral cues to deception and the indirect pathway of intuition. In Deception Detection in Forensic Contexts, Granhag, P.A., and L. Stromwall, eds. Cambridge: Cambridge University Press.
Ekman , P., & Friesen, W. V. (1969). Nonverbal Leakage and Clues to Deception. Psychiatry. 32, 88-106.
Ekman, P., & Friesen, W. V. (1974). Detecting deception from the body or face. Journal of Personality and Social Psychology, 29, 288-298.
Ekman. P., & O’Sullivan. M. (1991). Who can catch a liar? American Psychologist, 46, 913-920.
Faigman, D. L., Fienberg, S. E., & Stern, P. C. (2003). "The Limits of the Polygraph." Issues in Science and Technology. Retrieved 12 April 2005 from .
Ganis, G., Kosslyn, S. M., Stone, S., Thompson, W. L., & Yurgelun-Todd, D. A. (2003). Neural correlates of different types of deception: An fMRI investigation. Cerebral Cortex, 13, 830–836
Hyman, R. (1989). The psychology of Deception. Annual Review of Psychology. 40, 133-154.
Kohnken, G. (1987). Training police officers to detect deceptive eye witness statements: Does it work? Social Behavior, 2, 1-17.
Kleinmuntz, B., & Szucho, J. J. (1984b). In Raskin, D. C. (1988). Does science support polygraph testing? Barland, G. H. (1988). In A. Gale (Ed.), The polygraph test. Lies, truth and science. London: Sage. 73-95.
Kraut, R.E., & Poe, D. (1980). Behavioural roots of person perception: The deception judgments of customs inspectors and laymen. Journal of Personality and Social Psychology. 39, 784-798.
L. A. Farwell and E. Donchin. Talking off the top of your head: Toward a mental prosthesis utilizing event-related brain potentials. Electroencephalography and Clinical Neurophysiology, 70:510-523, 1988.
Mann, S., Vrij, A. & Bull, R. (2004). Detecting True Lies: Police Officers' Ability to Detect Suspects' Lies. Journal of Applied Psychology. 89, 137-149.
National Research Council (2003). The polygraph and lie detection. Committee to Review the Scientific Evidence on the Polygraph. Washington, DC: The National Academic Press.
Raskin, D. C. (1988). Does science support polygraph testing? In A. Gale (Ed.), The polygraph test. Lies, truth and science. London: Sage. 96-110
Summers, C. (2005) The future of lying. Retrieved 12 April 2005 from http://news.bbc.co.uk/go/pr/fr/-/2/hi/uk_news/magazine/4169313.stm
Wallace, P. (1999). The Psychology of The Internet. Cambridge. UK. Cambridge University Press.
Wilcox, D. T., & Sosnowski, D. E. (2005). Polygraph examination of British sexual offenders: A pilot study on sexual history disclosure testing. Journal of Sexual Aggression. 11, 3-26.
