The simple answer is, no. You can now go back to work, content in that little tidbit of brain knowledge.
Functional magnetic resonance imaging (fMRI) is a fancy name for a brain scan that purportedly measures “brain activity.” What it actually measures is simply changes in blood oxygenation and flow in your brain, which we believe to be directly related to brain activity — but this is an indirect measure at best. It’s not actually measuring “brain activity.” fMRI scans are most often used in research to try and better understand our brains and how other things affect our brains (like mental illness or a specific cognitive activity).
So you can imagine the challenges that might be faced when you connect this kind of brain measurement to a legal proceeding. A review article on the use of fMRI for lie detection basically found that the science isn’t there.
Researchers cannot even reproduce their own findings when it comes to fMRI, which is the core and basic tenet of research. If results are not reliably and consistently reproduceable, what you have discovered is a random effect, not a reliable scientific finding.
Vaughan over at Mind Hacks has the full story and a lot more commentary about recent court cases that Wired has covered about defendants now trying to get fMRI scans admitted into evidence as a lie detection evidence. Vaughan is far more optimistic about the fMRI lie detection data than I am — I believe the core scientific foundation doesn’t even exist for this technique. He believes there may be enough data to piece together using an fMRI as one possible datapoint of evidence in a court case:
Most of the arguments from neuroscientists focus on the scenario where someone ‘might be sent to prison’ on the basis of fMRI evidence, but Schauer notes that this is only a tiny proportion of court cases and that evidence should be evaluated depending on the context.
This, Schauer says, could be where technology like fMRI lie detection could play a part. If it is 60% reliable and is simply a small part of a larger picture it seems daft to not allow it when similarly ‘unreliable’ evidence is admitted all the time. As he notes “Although slight evidence ought not to be good enough for scientists, it is a large part of the law.”
I don’t know. If I have a technique that is basically little better than chance to determine if you’re lying, that hardly seems very scientific. Or useful. Might as well roll some dice or flip a coin to determine if a person is lying. Worse, if you can’t reproduce that result reliably, then it really is no better than flipping a coin.
People have the mistaken belief that lie detection is widely accepted, reliably administered, and easily interpreted, but nothing could be further from the truth. Lie detection instruments as they exist today vary in their reliability and evidence from lie detection interviews is rarely admitted into court. Despite lie detection’s problems, it is still used regularly in job screening and sensitive positions, like the FBI. fMRI is an attempt to improve the science behind lie detection, but it’s still at its earliest stages and has a long way to go before it becomes reliable.
Read the full article: fMRI lie detection and the Wonder Woman problem
I wanted to add an issue regarding the efficacy of lie detection. As many people in the UK are aware there is a TV program called; â€˜The Jeremy Kyle Showâ€™ this is a daytime ITV television talk show which has been broadcasting since 4th July 2005.
The show is extremely popular and distinctive for its confrontational style, which sees guests attempt to resolve issues with family and friends, very similar to that of â€˜Jerry Springerâ€™ in the US.
On the show they exhibit ‘The Lie Detector Test’ which is advertised as being at least 96-97% accurate. The evidence is gathered by using a â€˜Polygraph Testâ€™.
â€˜The Polygraph Testâ€™ results are generated by attaching 4 components to the subject. They then trace changes to the subjectâ€™s relative blood pressure and pulse rate and it is similar to the pressure cuff your doctor uses when taking your blood pressure.
â€œThe results compiled can and do change peopleâ€™s lives forever. Surely this cannot be a valid account of truth and must only propose an emotional relation to the questions at hand when administered?â€
Dawn Pugh MBACP
Yes, certainly proponents of polygraphs will say it is “nearly impossible to beat” (not you, but others) and certainly I expect their trade association to say the same things.
But traditional polygraph tests are based upon 3 simple physiological components, all of which a person can learn to control if they want — breathing, blood pressure and sweating. Yes, biofeedback, for instance, can teach you how to gain control of all 3 of these things, and it’s easily learned and practiced.
At least with brain imaging, we’re talking about something you couldn’t beat so readily with biofeedback and relaxation techniques. So it does hold out hope for the future of lie detection, it’s just that we’re not really there yet.
If fMRIs are so “unreliable”, then how come several studies that have been conducted have proved that they do detect when the brain is lying?
Yes, like all other ‘sources’ their results can be skewed, but so can polygraphs. Ever heard of false negative, and false positive?