E-SKEPTIC FOR JULY 25, 2002
Copyright 2002 Michael Shermer, Skeptics Society, Skeptic
magazine, e-Skeptic magazine (www.skeptic.com and skepticmag@aol.com).
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Per my description of humans as pattern-seeking,
storytelling animals. Only some are more pattern-seeking than others, even
when there is no pattern to be found, and now it looks like we have an
additional causal variable in explaining why that is.
Paranormal Beliefs Linked to Brain Chemistry
by Michael Shermer
New
Scientist 24 July 02
Whether or not you believe in the paranormal may depend
entirely on your brain chemistry. People with high levels of dopamine are more
likely to find significance in coincidences, and pick out meaning and patterns
where there are none. Peter Brugger, a neurologist from the University Hospital
in Zurich, Switzerland, has suggested before that people who believe in the
paranormal often seem to be more willing to see patterns or relationships
between events where skeptics perceive nothing. To find out what could be triggering these
thoughts, Brugger persuaded 20 self-confessed believers and 20 skeptics to
take part in an experiment. Brugger and his colleagues asked the two groups to
distinguish real faces from scrambled faces as the images were flashed up
briefly on a screen. The volunteers then did a similar task, this time
identifying real words from made-up ones.
Seeing and believing
Believers were much more likely than skeptics to see a
word or face when there was not one, Brugger revealed last week at a meeting
of the Federation of European Neuroscience Societies in Paris. However,
skeptics were more likely to miss real faces and words when they appeared on
the screen. The researchers then gave the volunteers a drug called
L-dopa, which is usually used to relieve the symptoms of Parkinson's disease
by increasing levels of dopamine in the brain. Both groups made more
mistakes under the influence of the
drug, but the skeptics became more likely to interpret scrambled words or
faces as the real thing. That suggests that paranormal thoughts are associated
with high levels of dopamine in the brain, and the L-dopa makes skeptics less
skeptical. "Dopamine seems to help people see patterns,"
says Brugger.
Plateau effect
However, the single dose of the drug did not seem
to increase the tendency of believers to see coincidences or relationships
between the words and images. That could mean that there is a plateau effect for them,
with more dopamine having relatively little effect above a certain threshold,
says Peter Krummenacher, one of Brugger's colleagues. Dopamine is an important
chemical involved in the brain's reward and motivation system, and in addiction. Its role in the reward system
may be to help us decide whether information is relevant or irrelevant, says
Franse Schenk from the University of Lausanne in Switzerland.
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