Remember it doesn't have to actually work. It just has to be either accepted in court, or believed to work by security agencies - just like polygraphs.
@echowit - that's not the problem, the problem is that since this is a big expensive box it must be correct.
So simply scan each applicant for a job requiring security clearance and don't hire those who show a red light.
Then start checking airline passengers/potential terrorists and those whose brain shows nervous activity when you show them 9/11 footage you put on a watch list.
Then you check all teachers/scout masters/etc, show them child pornography and black list those that show brain activity.
No need for this ever to be tested in court, no need for any scientific facts to be involved - just like polygraphs.
And of course it must be accurate - look how big and expensive it is!
@Curious - it's not that fMRI doesn't work - it is perfectly good at showing different regions of the brain being used. The danger is in the conclusion being drawn from the results.
There was a famous study that had white Americans pronounce African names and English names. The fMRI showed different areas of the brain were being used - hence the people were intrinsically racist.
So if you have to think differently to pronounce "Jakaya Kikwete" rather than "George Bush" the brain scanner proved you are a racist.
Photo of Bruce Schneier by Per Ervland.
Schneier on Security is a personal website. Opinions expressed are not necessarily those of Co3 Systems, Inc..