Thursday, 19 June 2014
Can fMRI Tell If You’re Lying?
The
simple answer is, no. You can now go back to work, content in that little
tidbit of brain knowledge.
So
you can imagine the challenges that might be faced when you connect this kind
of brain measurement to a legal proceeding. Areview 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
