NewScientist.com has an interesting article about US Department of Defense proposal to develop a lie detector that can be used without the subject knowing they are being assessed.

Yet another (secret) surveillance gadget to be added to an already staggeringly powerful state apparatus. And yet another machine that adds to the massive intelligence data overload that -- more often than not -- obscures possible threats and targets rather than highlight them.

It won't be long before the system beats itself, so we don't have to.