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Brain Scans to Identify Liars?
dotc writes "After a bunch of sci-fi stories and rumors, now it looks like the future has become a reality -- a reliable, unbiased test using functional MRI brain scan to detect lying. The article author details a first-person account of undergoing the MRI 'deception task'. And the test is available now - use it to prove your innocence." From the article: "Laken said he's aiming to offer the fMRI service for use in situations like libel, slander and fraud where it's one person's word against another, and perhaps in employee screening by government agencies. Attorneys suggest it would be more useful in civil than most criminal cases, he said."
I think this works better then a Polygraph
Almost anything works better than a polygraph. They have a ridiculously high rate of false-positives and false-negatives.
What's more ridiculous is that many US govt agencies, despite ample scientific proof, still use polygraphs.
Basically, you're looking for signs of psychological stress.
No, this is wrong. fMRI looks at blood oxygen levels (BOLD) in the brain - which indicate what part of the brain is being used. Lying requires more brain horsepower than telling the truth and the parts of the brain used for lying are known. They are different than just recall. This is indeed looking into the brain working and not a side effect like sweating. The recall parts of the brain are known too and thus can be used to determine if you've know a person. Flash a photograph of the person and if the recognition part fires, then it shows you've seen that person. You don't even have to punch a button...
Having said that, near IR is a much easier technique to look into the brain and only requires strapping some IR emitters/detectors on the subjects forehead. A link is here. Cost is way less than the millions for an fMRI that requires a supercon magnet and Faraday cage. And the subject need not be as cooperative.
No. The way the truth detection works is by comparing what happens when answering a set of different questions. There are easy ones and there are problemetical ones (like "did you strangle your mother in law?"). You need to have in the easy ones in the mix so that you can determine the baseline for truthful reactions. You need to do this with brain scans too because because people do not have identical brains. (Relatives of autistic people often show MRI abnormalities typical for the autism even though they are not symptomatic).
In old times when StB guys (= Czech version of KGB) trained their agents to defeat polygraph, the instruction went like this: "Imagine some very embarassing moment, some fact about you, something you did that would discredit you, something you do not want to be ever revealed. You don't say what it is but bring it up vividly in your memory when you are answering the easy control questions."
This technique of beating polygraph required serious training - while being hooked up to a polygraph - and it could fail if the tested person was not calm + composed, etc. But the point is that any method has a possible countermethods so we should not be too arrogant about "unbeatable brain scan"
I doubt that we will ever figure out - and I suspect that even if we did figure out we couldn't do much about it