The programme quotes a 90% accuracy for fMRI lie detection, but this is a best estimate and has been found in group studies, in lab conditions, where the lies are relatively benign – such as saying you haven’t seen an image when you’ve been shown it earlier.
It’s not clear how well they detect highly motivated lies. Also, it seems that the brain scans are better at detecting lies than truths.
This is important, because you could get a 100% lie detection rate by classifying everything as a lie. Being able to adequately separate truth and lies is the key to accuracy.
The first episode tested two ex-Guantanamo bay detainees accused of being terrorists but eventually release without charge, the second tested a woman convicted of poisoning her daughter with salt who protests her innocence.
Needless to say, the results are largely inconclusive.
If the technology were any better, I’d write in and see if they can get Tony Blair for the grand finale.
The best thing about the programme is Prof Sean Spence, who’s done some of the key research studies on the neuroscience of lying and fMRI lie detection, and does his best to point out the ambiguity of the whole process.
UPDATE: Thanks to Deception Blog for pointing out that the series is available over the web for viewers in the UK or Eire via Channel 4′s on demand service. It’s on some private bittorrent trackers but I’ve not seen it on any publice ones yet. Keep a look out.