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Brain-Scan Lie Detection Rejected By Brooklyn Court
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."
Nice tech, but it's not there yet.
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.....
I want peace on earth and goodwill toward man.
We are the United States Government! We don't do that sort of thing.
fMRI has been shown to be 76-90% accurate
That's certainly better than a weatherman but not good enough to convict someone.
If it is better than what we have for false convictions than why prefer human prejudice/error over machine error.
Because one of the reasons we have a jury system is to provide a check and balance on the ability of the government to lock people up. Jury nullification may be a bad word in the modern legal system but it's still there.
I want peace on earth and goodwill toward man.
We are the United States Government! We don't do that sort of thing.
Absolutely no lie detector will ever be able to tell the difference between "this is true" and "at this moment, the suspect believes that this is true". With some mental training (or, you know, schizophrenia) it's entirely possible to temporarily convince yourself that the sky is purple, and there's basically no way any machine will be able to pick up on it in the foreseeable future.
No judgment should ever rely on "the machine says he thinks its true, therefore he is guilty" - no matter how accurate the machine is.
Instead, we rely on "these 12 guys who have been struggling to stay awake during the proceedings think it's true, therefore he is guilty."
Go green: turn off your refrigerator.
I wouldn't be sure to trust this brain energy pattern recognition for a verdict- as far as I am concerned, it is much better to cut loose someone that _might_ be guilty, than to convict someone that is not.
The three laws of thermodynamics:(1) You can't win. (2) You can't break even. (3) You can't even quit.
This sort of thinking (that if the accuracy rate is improved enough it will become a valid way of determining someones guilt) shows a fundamental misunderstanding of statistics. It is the same reason blanket drug testing doesn't work and medical screening can sometimes be a bad thing.
Let's imagine for a moment that this lie detector technology has been perfected to a 99.99% accuracy rate. Since the test is so accurate, we decide that whenever a crime is committed, we will just have everyone in the area take the lie-detector test, asking them the question "Did you commit the crime?". Clearly, when someone fails the test, they are 99.99% likely to be the criminal. Right?
Except no. In cases like this (where the average person is much much much more likely to NOT be the criminal, the error rate will overwhelm the actual guilty-rate. If we are testing everybody in an area, then we can suppose that each person we check has an average chance of being the criminal of about 1 in however many we are checking. If this number we are checking is very large, then we are CERTAINLY going to have quite a few people who are found to be guilty on the test but are actually innocent. It will pick out more innocent people than guilty people.
While this sort of statistical phenomena will not take place if we don't giving blanket tests to everyone and limit the test to people who we already believe are very likely to have committed the crime, we as a society have a very bad tendency to not understand the statistics and think we should just give everyone the test and let the results tell us who is guilty. If you doubt this, just look at how many people think we should have a DNA database that everyone needs to join (so we can just run any DNA found at a crime scene against it). This combines the birthday paradox with the statistics I described above to create a situation where we have a very real fear of false convictions, exacerbated by the fact that people who are relying on this evidence (juries) do not realize that even a test with 99.999% accuracy can have a very high false positive rate in these sorts of circumstances.
Check out http://en.wikipedia.org/wiki/Bayes'_theorem#Example_1:_Drug_testing for more info on the math behind this.
Citation needed.
"Proof beyond a reasonable doubt" is not a formula or a slogan, to be sold, like Ivory soap, as "99 and 44/100% pure."
It only means, that in the light of all the evidence presented, the jury can in good conscience say that the defendant's guilt has been proven to their satisfaction and that any questions which remain will not alter their decision.