Gifted few make order out of chaos
19:00 06 March 2002 Exclusive from New Scientist
Print Edition, Rachel Nowak, Melbourne

Some people have a special gift for predicting the twists and turns of chaotic systems like the weather and perhaps even financial markets, according to an Australian psychologist.

Richard Heath, who has now moved to the UK's University of Sunderland tried to identify people who can do this by showing volunteers a list of eight numbers and asking them to predict the next four. The volunteers were told that the numbers were maximum temperatures for the previous eight days. In fact the numbers were computer-generated: some sets were part of a chaotic series while the rest were random.

Random sequences are by their nature unpredictable, whereas chaotic sequences follow specific rules. Despite this, chaotic sequences are very hard to predict in practice because of the "butterfly effect" - even an unmeasurably small change in initial conditions can have a dramatic impact on their future state.

Nonetheless, Heath found that a quarter of the people he tested could predict the temperature for at least the next two days if the sequence was chaotic, rather than random, even though there is no obvious pattern to the figures.

"The $64,000 question is what is going on in their heads," says Heath. He is now planning studies to find out whether the skill is related to specific personality types, or to aspects of intelligence such as mathematical ability.

No cheating
David Gilden, a psychologist at the University of Texas in Austin, doubts that people can detect the next step in any sequence that lacks a perceptible pattern. "It's a strong claim, to assert that the skill only exists implicitly," he says.

But others are convinced that Heath is onto something. "It's sound. The effect looks real," says artificial intelligence expert Jeff Pressing of the University of Melbourne.

He and others point to a crucial difference between this and previous studies claiming to show that people can identify the patterns in chaotic systems: Heath distinguished between the effects of chaos and other characteristics of the sequences that might help people make correct predictions.

In particular, Heath was able to exclude the possibility that the people making successful predictions were doing so by looking only at the last few numbers. In other words, they were not able to cheat by assuming that "the weather tomorrow is likely to be the same as the weather today".

If the finding does stand up, testing for sensitivity to chaos might help financial institutions identify people who would do well as financial traders. "Some guys can't communicate what they are doing, but they make millions," says Pressing. "They have some sort of intuition. My guess is that they are sensitive to subtle non-linear structures like chaos."

Journal reference: Nonlinear Dynamics, Psychology, and Life Sciences (vol 6, p 37)
Original doc found at http://www.newscientist.com/article.ns?id=dn2003