Caught in a lie… by your brain

Polygraphs move over, it’s been a good 100 years but its time for a new tool now. The future of lie detectors may very well be found in the brain, well the reading of the brain to be precise. Functional magnetic-resonance imaging (fMRI) is thought to be able to tell if a person is lying.

In short:

“fMRI scanners detect variations in the magnetic properties of blood as oxygen levels change in response to neural activity. The more a section of the brain works, the more oxygen it demands and the brighter it glows on the scan.” It is believed that when a person is lying certain parts of the brain are working (lighting up) in a particular pattern, termed as a “deceit pattern”.

Recently reported in Popular Science magazine, two companies are working on Lie Detecting MRIs. Thanks to the increasing admission of MRI evidence in court cases, there is now an opening for MRI lie detector evidence to be used in courts as well.

It should be noted that there is no such things as a true lie detector. The one that the majority of the public has come to know of is called a polygraph, which measures physical responses like blood pressure and pulse during questioning. There is much debate to this day about the credibility of the polygraph as a lie detector since the factors that cause it to produce results consistent to lying, can also be achieved from a person who is nervous or stressed during the interrogation.

I personally believe that fMRI lie detectors are no better or more accurate then the current 100-year-old polygraph. While fMRI machines are useful tools in the medical field, they are by no means perfect. In an article published by WIRED magazine. It was found that a dead salmon being used in testing an fMRI at Dartmouth apparently showed results of having brain activity.

Photo from WIRED magazine

This shows that MRI results used for the sake of mapping “deceit patterns” in a brain may not be as accurate as one would hope when possibly passing a life sentence or death penalty. Another problem found with using a fMRI result for lie detecting purposes is that no two brains are alike, and the variations in brains makes it difficult to establish a base line to compare the subjects brain scans too. While I am in no way saying that fMRI results are worthless and should not be used, I am just saying they are not fool proof enough to be used as lie detector evidence in a court of law.