Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
The Courts United States

Brain-Scan Lie Detection Rejected By Brooklyn Court 197

blair1q writes "A judge in Brooklyn has excluded Functional Magnetic Resonance Imaging (fMRI) lie-detector evidence from a trial there. However, the decision will not set a precedent, as it was made without even conducting a hearing on the method's validity, but on the principle, argued by the defense, that 'juries are supposed to decide the credibility of the witness, and fMRI lie detection, even if it could be proven completely accurate, infringes on that right.' That principle can be tested in later hearings, such as one scheduled for May 13, 2010, in Tennessee; in this case, the defense wants to use fMRI evidence it has already collected to prove its client is innocent. fMRI has been shown to be 76-90% accurate. That number seems significantly larger than the rate of false convictions."
This discussion has been archived. No new comments can be posted.

Brain-Scan Lie Detection Rejected By Brooklyn Court

Comments Filter:
  • by Mekkah ( 1651935 ) on Thursday May 06, 2010 @04:10PM (#32116512) Journal
    They don't tell you shit, I've taken a couple of them for government work and it depends on the person, and their ability to concentrate. You can easily get false positives and easily beat it if you have the right mindset.
  • by Anonymous Coward on Thursday May 06, 2010 @04:19PM (#32116662)

    What happens to the right to remain silent when it is there? The British have already gutted this right. Not that hard to envision the same happening here.....

    It's a lie detector not a mind reader. If you look into this and other lie detectors it becomes quickly obvious that no application can ever approach 99.9% accuracy. Humans and the reasons they lie are too varied to ever be categorized. Lie detectors are part interrogation and part snake oil and there is a 0% chance they can be made reliable.

    Food for thought: Scientologists currently use more sensitive lie detectors than the FBI.

  • Re:Lie Detection (Score:3, Interesting)

    by AtomicDevice ( 926814 ) on Thursday May 06, 2010 @04:42PM (#32116990)
    Very true.

    Even the best "lie detector" could only prove what someone believed or remembered to have happened. Many studies have shown memories to be very open to manipulation, children have been convinced by their doctors that they were raped by their own parents (when they were not). People have been manipulated to believe that certain individuals (who look nothing like the real perpetrators) committed acts of violence against them.

    Even without overt manipulation, eyewitness testimony is notoriously unreliable, and there is no reason to believe that even suspects who have not been coerced might come to believe falshoods about their own actions through some combination of internal and external pressure.

    Furthermore, as one with personal experience with fMRI data analysis, the though of using fMRI to sentence someone to years in prison or worse is frightening. While over large sample groups certain types of analysis can be reliable, fMRI data is frought with noise, is very low resolution (both spatially and temporally), and due to the huge amount of pre-processing required to get any useful data, would be very vulnerable to manipulation by unscrupulous types (or merely accidental bad analysis by poor technicians or bad software).
  • Re:Gaming the system (Score:2, Interesting)

    by linzeal ( 197905 ) on Thursday May 06, 2010 @04:44PM (#32117030) Homepage Journal
    A fMRI is not a lie detector test it is more of a memory test, so unless the criminal is delusional or has those morphological differences I mentioned in my first post he is not going to get off.
  • by cheesethegreat ( 132893 ) on Thursday May 06, 2010 @04:44PM (#32117034)

    Here is the interesting hypothetical:

    Assume this lie-detector is right 80% of the time, and that its success/failures are randomly distributed (e.g. not associated with socio-economic background).
    Assume also that false conviction rates are at 21% (so only 79% of convictions are correct), and that there is substantial evidence that this is not evenly distributed (e.g. that false convictions are associated with low socio-economic status).

    Would you be willing to entirely replace the system of jury trials with trial by lie detector?

  • by 2obvious4u ( 871996 ) on Thursday May 06, 2010 @05:09PM (#32117386)
    Grant beat it by doing complex math in his head while they asked him questions. Couldn't find a video, but found summary. [mythbustersresults.com]
  • by izomiac ( 815208 ) on Thursday May 06, 2010 @06:06PM (#32118144) Homepage
    This is why I'm curious as to the appeal of lie detectors in courtrooms. If there was an actual physiological change associated with lying, then the whole concept of lawyers and courtrooms becomes obsolete. Asking "Have you committed a crime?" with confirmation from the lie detector would be all that's required. Heck, police could start doing it to all suspects with portable versions, and drop off the people who failed at the local prison. The only point of a judge would be to determine sentence length, which, with a way to know what actually happened and what the motivations were, would basically lead to that just being a checklist. The suspect knew it was illegal? Add 6 months to the sentence.

    Now, returning from our trek in fantasy land, lie detectors cannot work. Some people are terrible liars, but you can tell that in a jury trial. Others legitimately believe what they say to be the truth. "Did you commit a crime?" being a prime example. Serious criminals simply do not think like ordinary folk, a fact that should be obvious since ordinary folk (>98-99%) do not commit serious crimes. OTOH, for the situational crimes, the criminal's perception of reality is what would be detected by the lie detector, which probably has little resemblance to actual reality. Situational criminals don't knowingly do something evil, so they aren't "lying", whereas people who have the capacity to knowingly be evil aren't going to be flustered enough to be detected on a lie detector test.
  • by BobMcD ( 601576 ) on Thursday May 06, 2010 @06:12PM (#32118210)

    Would you be willing to entirely replace the system of jury trials with trial by lie detector?

    To do so would ignore the brilliance of the system, and would emaciate the only good feature of it: popular justice.

    See, the notion of a 'jury of your peers' isn't about proving innocence or guilt, per se, but is more about the people getting to participate in seeing their democratic laws justly applied.

    E.g. 'jury nullification'.

    Removing this element wouldn't be serving the people to the same degree the current system does.

  • by ami.one ( 897193 ) <amitabhr@gmai l . com> on Friday May 07, 2010 @01:21AM (#32122602)
    Interestingly, just a few days back the Supreme Court of India banned [indiatimes.com] any forced polygraph/Narco/Brain Mapping Tests as they violate the constitution as well as the privacy of a citizen, are essentially asking a person to testify against himself, are as bad as torture, and are no better than getting a person drunk .
  • by droopus ( 33472 ) * on Friday May 07, 2010 @05:59AM (#32124048)

    Hoo boy some of the cases I've seen are so egregious they would spin your head. One example:

    Limo driver picks up client at JFK. Puts suitcases in the trunk. DEA and FBI surround and stop the limo on the Van Wyck Expressway 3 miles out of the airport. Client hustles out of limo, runs away, never seen again. Suitcases contain 20 kilos methamphetamine, 10 kilos tar heroin.

    Limo driver, totally innocent refused 10 year plea bargain, as anyone would. Jury finds him guilty of conspiracy...he gets 35 years in the feds, then will be deported, even though he's had his green card for 15 years.

    This is the US justice system. CSI, Law and Order are worse than fiction....they are propaganda.

Beware of Programmers who carry screwdrivers. -- Leonard Brandwein