Jump to content

Lie detection

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by Jamesdoshea (talk | contribs) at 11:30, 29 October 2011. The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Lie detection is the practice of attempting to determine whether someone is lying. Activities of the body not easily controlled by the conscious mind are compared under different circumstances. Usually this involves asking the subject control questions where the answers are known to the examiner and comparing them to questions where the answers are not known. Critics claim that "lie detection" by use of polygraphy has no scientific validity because it is not a scientific procedure.[1]

Polygraph

Lie detection commonly involves the polygraph. Voice stress analysis may also be commonly used because it can be applied covertly to monitor voice recordings. The polygraph detects changes in body functions not easily controlled by the conscious mind. These include bodily reactions like skin conductivity and heart rate.[2]

Cognitive polygraph Recent developments that permit non-invasive monitoring using functional transcranial Doppler (fTCD) technique showed that successful problem-solving employs a discrete knowledge strategy (DKS) that selects neural pathways represented in one hemisphere, while unsuccessful outcome implicates a non-discrete knowledge strategy (nDKS).[3] A polygraphic test could be viewed as a working memory task. This suggests that the DKS model may have a correlate in mnemonic operations. In other words, the DKS model may have a discrete knowledge base (DKB) of essential components needed for task resolution, while for nDKS, DKB is absent and, hence, a "global" or bi-hemispheric search occurs. Based on the latter premise, a 'lie detector' system was designed as described in United State Patent No. 6,390,979. A pattern of blood-flow-velocity changes is obtained in response to questions that include correct and incorrect answers. The wrong answer will elicit bi-hemispheric activation, from correct answer that activates unilateral response. Cognitive polygraphy based on this system is devoid of any subjective control of mental processes and, hence, high reliability and specificity; however, this is yet to be tested in forensic practice. See also cognitive biometrics.

fMRI

Studies using functional magnetic resonance imaging (fMRI) have shown that it has potential to be used as a method of lie detection.[4] While a polygraph detects changes in activity in the peripheral nervous system, fMRI has the potential to catch the lie at the ‘source’. However, the neurobiological systems that relate to lying are currently poorly understood. The current consensus is that faced with a forced choice paradigm, in which a subject has the choice of telling the truth or spontaneously generating a lie, lying can be distinguished due to increased prefrontal and parietal lobe activity. More specifically, the superiormedial and inferolateral prefrontal cortices show net activation in the process of spontaneous lie generation (which involves suppression of the truthful response as well as generating a conceivable lie). Subjects are often offered monetary incentive if they can successfully deceive the process in hopes of generating a ‘real world’ scenario. Using this method, studies have shown that lies can be distinguished 78% of the time.[5] That statistic can rise as high as 85–90% when predicting a lie in an individual whose baseline lie/truth levels have been closely studied, although this does rely upon the individual being co-operative.[6]

There are currently two companies: No Lie MRI Inc.[7] and Cephos Corporation[8]) who plan to advance this technology for commercial use.

In episode 93 of the TV program Mythbusters, the three members of the build team attempted to fool an fMRI test. Although two of them were unsuccessful, the third was able to successfully fool the machine by keeping his mind in constant activity, suggesting that fMRI-based lie detection still requires further development.[9]

Brain observations

Electroencephalography is used to detect changes in brain waves.

Brain fingerprinting uses electroencephalography to determine if an image is familiar to the subject. This could detect deception indirectly but is not a technique for lie detecting.

Cognitive chronometry, or the measurement of the time taken to perform mental operations, can be used to distinguish lying from truth-telling. One recent instrument using cognitive chronometry for this purpose is the Timed Antagonistic Response Alethiometer, or TARA.

Brain-reading uses fMRI and the multiple voxels activated in the brain evoked by a stimulus to determine what the brain has detected, and so whether it is familiar or not.

Non-Verbal Behaviour

Non-invasive lie detection using non-verbal behaviour is performed by the Silent Talker Lie Detector. Silent Talker monitors large numbers of Microexpressions over time slots and encodes them into large vectors which are classified as showing truthful or deceptive behaviour by artificial intelligence or statistical classifiers. Silent Talker research has been peer-reviewed in the Journal of Applied Cognitive Psychology [10] and in the Journal of Neural Computing and Applications [11].

Drugs

Truth drugs such as sodium thiopental and marijuana (historically speaking) are used for the purposes of obtaining accurate information from an unwilling subject.[12] Information obtained by publicly disclosed truth drugs has been shown to be highly unreliable, with subjects apparently freely mixing fact and fantasy.[13] Much of the claimed effect relies on the belief of the subjects that they cannot tell a lie while under the influence of the drug.

Controversy

In the peer-reviewed academic article "Charlatanry in forensic speech science", the authors reviewed 50 years of lie detector research and came to the conclusion that there is no scientific evidence supporting that lie detectors actually work.[14] Lie detector manufacturer Nemesysco sued the academic publisher for libel and forced a removal of the article from the online databases. In a letter to the publisher, Nemesysco's lawyers wrote that the authors of the article could be sued for defamation if they wrote on the subject again.[15][16]

The cumulative research evidence suggests that machines do detect deception better than chance, but with significant error rates[citation needed] and that strategies used to "beat" polygraph examinations, so-called countermeasures, may be effective.[17] Despite unreliability, results are admissible in court in some countries such as the United States.

Clark Freshman, Professor of Law at University of California, Hastings College of Law, studies lies in negotiations and lies involving lawyers. Together with Michael Wheeler at Harvard Business School, he developed a series of clips of how lies – and concealed emotions – show up in real estate negotiations. His scholarship on lies and negotiations goes well beyond Paul Ekman's original theories. Freshman and Wheeler found microexpressions of emotion and other clues in their research on negotiation[citation needed].

See also

References

  1. ^ The Lie Behind the Lie Detector by George W. Maschke and Gino J. Scalabrini
  2. ^ Forensic Psychology. BBC Science & Nature.
  3. ^ Njemanze, P. C. (2005). Cerebral lateralization and general intelligence: Gender differences in a transcranial Doppler study. Brain and Language, 92, 234–239
  4. ^ Ganguli, I. (2007). Watching the Brain Lie: Can fMRI replace the polygraph? The Scientist, 21, 40
  5. ^ Spence, S.(2008). Devil’s advocate†: The case against fMRI lie detection.Legal and Criminological Psychology. 13(1), 11-25(15).
  6. ^ No Lie MRI Inc.
  7. ^ Cephos Corporation
  8. ^ http://mythbustersresults.com/episode93
  9. ^ Rothwell, J. Bandar, Z. O’Shea, J. McLean, D. Silent talker: a new computer-based system for the analysis of facial cues to deception, Journal of Applied Cognitive Psychology, Volume 20, Issue 6, pages 757–777, September 2006. doi: 10.1002/acp.1204 Final article format: http://onlinelibrary.wiley.com/doi/10.1002/acp.1204/abstract
  10. ^ Rothwell, J. Bandar, Z. O’Shea, J. McLean, D. Charting the behavioural state of a person using a Backpropagation Neural Network. Journal of Neural Computing and Applications. DOI 10.1007/s00521-006-0055-9. 2006.
  11. ^ Kapoor, P., Chugh, Y., Kapoor, A. K. & Sinha, U. S. (2008). Torture, terrorist and truth serum. International Journal of Medical Toxicology & Legal Medicine. 10 (2)
  12. ^ Rowell Jr (1952). Admissibility of Evidence Obtained by Scientific Devices and Analyses. Florida Law Review. 5 (5).
  13. ^ Eriksson, A. & Lacerda, F. (2007). Charlantry in forensic speech science: A problem to be taken seriously. International Journal of Speech Language and the Law. 14 (2).
  14. ^ All lies? Scientists threatened with legal action over lie detector article. Stockholm University.
  15. ^ Threats over Swedish lie detector research. The Local. January 27, 2009.
  16. ^ The Truth About Lie Detectors. American Psychological Association.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Lie_detection&oldid=457957572"