http://www.sciencedaily.com/releases/2007/12/071212202008.htm
It has been found through fMRI (a non-invasive procedure akin to cat-scans) that there is a physiological centre in the brain for each of the following properties: Belief, Disbelief and Uncertainty. This ability to determine whether a person truly believes what they are saying could have huge effects on everything from placebo studies to criminology.
(It must be said that this does not say whether something is true or not, but whether it is believed to be true or not by the individual being scanned)
If such a technique were to be used in studies, court cases or whatever else, what are the implications for privacy? This would seem to me to be a form of unfalsifiable lie-detection. Simply a statement of "Do you believe statement A?" could answer all kinds of questions, particularily in court cases.
If I were to be in a court case for murder, and it was asked that I undergo this process to determine my guilt or innocence, should I have a right to abstain and have a trial under more conventional means, or would that lead to an assumption of guilt? If it leads to an assumption of guilt, should it?