I just read an article regarding FMRI and guilty knowledge which claimed that in a research study they successfully had people "suppress" guilty knowledge about a mock crime they committed and it went undetected while undergoing a subsequent FMRI brain scan. They apparently were able to train some people to intentionally suppress some of their memory specific to the mock crime, and thus, they did not get detected during the FMRI. I don't know how this will translate into the "real world" with real crimes, real emotions and real memories, but it is interesting none the less.
I have posted information in the past and had many discussions withe people about how people are looking for the panacea of lie detection, and many thought it was in FMRI brain scans. Unfortunately some countries currently use these within their criminal justice systems, and I believe it was India that was the first country to convict someone based primarily on “failing” a brain scan. This research casts further doubt about their reliability.
The most interesting thing about this to me is that it really highlights the importance of the human factor; the face-to-face interview or interrogation by a skilled practitioner. Regardless of the technology, there will always be a need for competent interviewers and interrogators to not only detect possible deception, but to effectively interact with the individual, develop rapport, ask appropriately targeted questions, elicit information and evaluate responses, and ultimately arrive at the truth. Even if a machine may (or may NOT) be able to tell if someone is lying, but it is the skill of the interviewer that will finally extract the TRUTH.