Use of magnetic resonance imaging as lie detector

MRI as a Lie Detector Lying has almost become an integral part of our daily routines. Studies have pointed out that one of three conversations contain a lie. The extent of lying varies from person to person and lying with criminal intent is viewed as more seriously. Polygraph, the traditional lie detector relies on recording the physical movements and vibrations of human organs to record unusual movements and accordingly comes out with the conclusion. Unusual variations in blood pressure, pulse rates, heart beats, respiration and skin conductivity, sweating etc are detected by a polygraph. It is believed that while lying, some or all of these factors record variations in the human body. These variations are then drawn on a paper with the help of multicolored probes. Experts then make a comparison with the standard recordings and detect the lies. But some experts also raise doubts on the effectiveness of such tests, because it is noticed that while a person is subjected to such tests, the anxiety and uneasiness also results in unusual heart beats and blood pressures. Similarly somebody, who’s aware of the functioning of Polygraph, he can control his activities by keeping himself cool. Such people generally happen to be habitual liars. The polygraph therefore ends up with an incorrect outcome. For this very reason, such tests are often not admissible under courts of law. Polygraph testing has not proved to be a foolproof method for detecting lies, during all these years. Therefore, researchers have been working on the methods for improving the standards of lie detection.

It is worthwhile here to mention that all physiological changes taking place in the human body are controlled by the human brain, so researchers thought of the idea of using a brain analyzer to detect the lies. MRI, i.e. Magnetic Resonance Imaging is a tried and tested technique to record the activities of brain. MRI is used to diagnose brain tumors using the functional magnetic resonance imaging (fMRI) scans (Reese, 2005). This technique uses a radio wave antenna and takes images of brain using the principle of nuclear magnetic resonance. Exposing the soft tissues to such magnetic rays is quite safe as compared to some other forms of diagnostic techniques like X-ray and CAT scans. Therefore researchers started studying how an MRI could be used as a lie detector. MRI has been found as working quite reliably even if a person tries to control his physical reactions and emotions. The brain stars ‘thinking’ as to how emotions are to be concealed and that forms an unusual activity, which is detected by the MRI. Therefore, MRI works quite effectively even in such cases where a polygraph test fails. In a typical working of MRI as lie detector, the person’s head is placed inside the MRI machine. A small gadget, having two switches, is handed over to him. Now the expert starts asking the person questions having answers in ‘Yes’ or ‘No’ form. The person undergoing ‘MRI Lie Detector test’ is required to press either of the two switches to say ‘yes’ or ‘no’. The computer in the adjacent room records the activities of 3-4 specified areas of the brain. If all the monitored areas light up, then the answer is detected to be a lie. Experts say that these areas light up because, the person is not ‘downloading’ the material as such from his memory, but he is trying to manipulate the stored memory to arrive at a new perceived truth. This technique has been aptly named as ‘No Lie MRI’. This technique has so far been found to almost 100 percent accurate as against about 60 percent accuracy in case of polygraph tests.

The huge cost of an MRI machine will probably impede the availability of these machines at all police stations and investigation centres, but a beginning is being made and things may not remain the same for ‘professional liars’.

1. Hitti, Miranda (2004). MRI: The Ultimate Lie Detector Available online at (Oct 7, 2007)
2. Reese, Jordan (2005). MRI lie detector may tell fact from fiction. Available online at (Oct 7, 2007)
3. RSNA (2004). ‘Brain Imaging with MRI Could Replace Lie Detector’. Radiological Society of North America. Available online at (Oct 7, 2007)
4. Babiar, Heather (2006). Who’s the liar Brain MRI stands up to polygraph test. (Oct 9, 2007)