somebody <x### [at] ycom> wrote:
> Just when I thought my opinion of humanity could not get any lower:

> http://www.nytimes.com/2009/11/04/world/middleeast/04sensors.html
> http://en.wikipedia.org/wiki/ADE_651
> http://www.ade651.com/ade651in.html

  You wouldn't believe how easily scientists themselves are fooled by
magicians and tricksters because they, for whatever reason, don't understand
the importance of some of the most basic scientifical testing, such as
double-blind controlled tests.

  The "double" there is quite important. Many scientists are way too
confident on their own capacity to not to influence the test results and
to interpret the results impartially.

  A "blind test" is when the subjects don't know the nature of the objects
being tested. For example, some people might be given real medicine while
others are given placebos, and these people don't know who is getting what.
But the testers know.

  A "double-blind test" is when the testers themselves don't know either
(only people who are completely detached from the testing procedure know,
or in some cases where it's possible, the objects are randomized so that
nobody knows before they are later revealed by examination). This way the
testers themselves cannot affect the outcome or have subconscious bias in
their interpretation of the results because they don't know either.

  As an example, James Randi went once to Russia (I think it was still the
Soviet Union back then) to test many so-called supernatural phenomena claimed
to being happening there. In one case some medical professionals were convinced
that a psychic was able to influence the blood pressure and other vital signs
of other people: They had made numerous tests and confirmed that people's
vital signs changed according to what the psychic claimed.

  James Randi was a bit sceptic about it and wanted to perform something that
they clearly hadn't been doing: A *double* blind test. Surprisingly, suddenly
the test results and what the psychic claimed became completely contradictory.

  The problem became clear: By knowing what to expect, the medical doctors
were interpreting the test results which was output by the machines to
conform the expectations. Even minor random variations seemingly confirming
the expected result were taken as confirmation, while opposing minor random
variations were simply discarded as minor and random. But of course
immediately when they didn't know what to expect, the interpretation became
equally random and didn't match what the psychic said at all.

  The doctors were clearly not malicious. They were simply subconsciously
biased and too confident on their own capacity to interpret the results
impartially.

-- 
                                                          - Warp

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