WHAT IS INTELLIGENCE? This may seem to be more of a question
for psychologists than physicists. But two researchers (Joseph
Wakeling, jwakeling@webdrake.net, now at the University of
Fribourg, Switzerland, and Per Bak, Imperial College, 011-44-20-
7594-8528, p.bak@ic.ac.uk) argue that intelligence is not an abstract
concept, but must be considered as a physical phenomenon. Any
definition of intelligence, they say, cannot ignore a living being's
environment, including its very own body. In their view, an organism
is only intelligent relative to how well it solves the problems that its
surroundings throw at it. This runs counter to many historical ideas,
including the concept that the mind is separate from the body, or that it
is possible to build a desktop computer that thinks like a human
without having the same physical environment or body. To explore the
idea of intelligence, the researchers ran computer simulations of
artificial neural networks called "minibrains." In the simulations, 251
minibrains each attempted to pick the less popular of two choices, 0
and 1, analogous to 251 motorists all trying to pick the less congested
road. This "Minority Game" would be repeated over many successive
rounds. Each minibrain consisted of three layers of "neurons": "input
neurons," which dictated how many past rounds it could remember,
leading to an intermediary layer, which then led into an "output" layer
that determined what choice was made. If the minibrain ending up
making an incorrect choice, it would reduce the strength of the
connections between neurons supplying the "wrong answer." The
researchers were in for a surprise when they endowed all of the
minibrains with equal abilities, which would be analogous to a bunch
of motorists with the same amount of decision-making skill. In this
situation, no minibrains correctly guessed the minority choice with
even a 50 percent success rate, which is what you'd get by making the
choice with a random flip of a coin. Even an E. coli bacterium, which
searches for glucose by moving in random directions in its
environment, is seemingly more intelligent than this. Only when the
researchers introduced a "rogue" minibrain with more intermediate
neurons to analyze the past rounds did it attain more than a 50 percent
success rate. Their simulations suggest that intelligence often hinges
on how much one can make use of the data in its physical
environment. (Wakeling and Bak, Physical Review E, November
2001)
[PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 563 October 30, 2001 by Phillip F. Schewe, Ben Stein, and
James Riordon]
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