http://www.newscientist.com/article/dn14694-superstitions-evolved-to-help-us-survive...
Superstitions evolved to help us survive
00:01 10 September 2008
NewScientist.com news service
Ewen Callaway

Darwin never warned against crossing black cats, walking under ladders or
stepping on cracks in the pavement, but his theory of natural selection explains
why people believe in such nonsense.

The tendency to falsely link cause to effect – a superstition – is occasionally
beneficial, says Kevin Foster, an evolutionary biologist at Harvard University.

For instance, a prehistoric human might associate rustling grass with the
approach of a predator and hide. Most of the time, the wind will have caused the
sound, but "if a group of lions is coming thereÂ’s a huge benefit to not being
around," Foster says.

Foster and colleague Hanna Kokko, of the University of Helsinki, Finland, sought
to determine exactly when such potentially false connections pay off.

Simplified behaviour
Rather than author just-so stories for every possible superstition – from lucky
rabbit's feet to Mayan numerology – Foster and Kokko worked with mathematical
language and a simple definition for superstition that includes animals and even
bacteria.

The pair modelled the situations in which superstition is adaptive. As long as
the cost of believing a superstition is less than the cost of missing a real
association, superstitious beliefs will be favoured.

In general, an animal must balance the cost of being right with the cost of
being wrong, Foster says. Throw in the chances that a real lion, and not wind,
makes the rustling sound, and you can predict superstitious beliefs, he says.

Real and false associations become even cloudier when multiple potential
"causes" portend an event. Rustling leaves and say, a full moon, might precede a
lion's arrival, tilting the balance toward superstition more than a single
"cause" would, Foster explains.

In modern times, superstitions turn up as a belief in alternative and
homeopathic remedies. "The chances are that most of them donÂ’t do anything, but
some of them do," he says.

Michael Shermer, publisher of Skeptic magazine, has proposed a similar
explanation for such beliefs, albeit in less mathematical language.

"Our brains are pattern-recognition machines, connecting the dots and creating
meaning out of the patterns that we think we see in nature. Sometimes A really
is connected to B, and sometimes it is not," he says. "When it isn't, we err in
thinking that it is, but for the most part this process isn't likely to remove
us from the gene pool, and thus magical thinking will always be a part of the
human condition."

Scientific superstition
Yet not all superstitions persist because of their evolutionary kick. "Once you
get to things like avoiding ladders and cats crossing the road, it's clear that
culture and modern life have had an influence on many of these things," says
Foster.

"My guess would be that in modern life, the general tendency to believe in
things where we don't have scientific evidence is less beneficial than it used
to be," he adds.

However, Wolfgang Forstmeier, an evolutionary biologist at the Max Planck
Institute of Ornithology in Starnberg, Germany, argues that by linking cause and
effect – often falsely – science is a simply dogmatic form of superstition.

"You have to find the trade off between being superstitious and being ignorant,"
he says. By ignoring building evidence that contradicts their long-held ideas,
"quite a lot of scientists tend to be ignorant quite often," he says.

Journal reference: Proceeding of the Royal Society B (DOI:
10.1098/rspb.2008.0981)

--
Frederick Martin McNeill
Poway, California, United States of America
mmcneill@fuzzysys.com
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