Post-modern polygraphs

Functional magnetic resonance imaging, or fMRI, and electroencephalography, or EEG, are the most promising modern techniques vying to replace the polygraph. One reason researchers think these methods might be superior is that instead of using sweat and heartbeat to tell us what's going on in the mind, these technologies map the brain itself. Another reason is that both methods are better suited than the polygraph to identifying whether the subject has guilty knowledge, and this is more useful in security screening than the highly targeted interrogation required by the control-question test.

From this story in Wired by Jennifer Granick. Her verdict?

At some point soon, these high-tech lie detectors will be cheap, accurate, portable and unobtrusive enough to replace the polygraph in incident investigations. But we are a long way from reading minds. [...]

With even the best technology, science says lie detection is still only a little better than a shot in the dark.