Retired police captain John Schweer was killed by a shotgun on July 22, 1977, while working as a security guard for a car dealership in Bluffs, Iowa. The key witness, Kevin Hughes, testified that Terry Harrington and another man were going to steal a car, and killed Schweer in the process. Harrington has declared his innocence since he was convicted 20 years ago. He claimed that he was at a concert that night and then, after the concert was over, he went out driving with friends. Witnesses testified to his alibi, but the jury believed Hughes. Harrington was convicted to life without parole.
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Lawrence Farwell, an Iowa-based neuroscientist, invented the "brain fingerprinting", a method that focuses on a specific electric brain wave, called a P300, which activates when a person sees a familiar object. The subject wears a headband of electrodes and faces a computer screen, which flashes photos. Patricia Wen in The Boston Globe says that "this technique provides a potential window into someone´s past visual experience. |
If a person looks at random pictures of weapons, without activating a P300 wave, these objects are presumably unknown to him. But if the murder weapon is shown, and a P300 activates, then the person clearly has some experience with that weapon". Farwell says that the technique "is used to see if they have the information stored in their brain or not. All of this relates indirectly to lie detection".
Farwell´s invention is one of many scientific efforts to substitute the old polygraph, in use since the 1920s. Mark Zaid, a Washington attorney who represents eleven different people who say they were unfairly rejected for federal law-enforcement jobs when they failed a mandatory polygraph test, consider the practice hardly better than a coin toss. He has a point here, as former CIA agent Aldrich Ames easily fooled lie-detector tests, concealing his work as a Russian spy.
A conversation about these matters on the Hypermail of www.bio.net puts forward interesting points:
If I am not mistaken, all the technology shows is
that the
> person has a certain memory encoded in his brain.
However, there is no
> way to determine if the memory is correct or where
it came from. So, if
> I were accused of say killing someone on the way
home from work at a
> particular bar which I do not frequent, the test
would try to show that
> I had a memory of the bar. Perhaps I visited the
bar while I was under
> investigation. The test could come up positive, because
I was in the
> bar. Plus I might have memories about the murder
from reading about it
> in the papers, seeing it on TV and questions from
the Police.
>
> I think the test definitely needs much more validation
before using it
> in court.
I very much agree. The test determines (to an unknown
degree of
reliability) that the displayed item is "recognized"
or "familiar". But
much depends on the way in which it is applied or interpreted.
And
the show (60 Minutes) did specify that a witness to a
crime would likely have the
same recognition to specific details as the perpetrator.
lt is also
probably not at all known whether specific individuals
might have
aberrant responses that would generate either false negatives
or
false positives.
Dr Farwell performed his brain fingerprinting on Terry
Harrington. From the testing with the activation of the
P300, he claims that there is no information present in
Harrington´s brain concerning the crime that would
not be known by anyone who sat through the trial. However,
there is information in Harrington´s brain concerning
events of the concert. While Dr Farwell will not say if
Harrington is guilty or innocent, he does state that the
information that is (or isn´t) in Harrington´s
brain is relevant and useful to help determine the truth
of the situation.
To make matters more complex, the prosecution's witnesses
started to say that they lied. Hughes came forward and
said that he had lied at Harrington's trial because he
did not want to be charged with murder and because he
thought he was going to get reward money. Another witness,
Candace Pride, stated that she agreed with Hughes because
she was Hughes's girlfriend at the time. Also, Clyde Jacobs
stated that he agreed to testify against Harrington to
stay out of trouble. Harrington´s motion for a new
trial was rejected. After reviewing evidence from all
sides, the judge did not grant a new trial, and Harrington
is appealing.