Be spontaneous (It may save your life)

Gerald Owen, National Post

Published: Friday, May 25, 2007

If I were a fruit fly, I think I would be annoyed to be made to fly about in an all-white chamber, with no visual stimuli. But I would be flattered if I understood I was being asked to help answer the age-old question of free will and determinism, which G.W. Leibniz, a mathematician, philosopher and logician, three centuries ago called a "famous labyrinth."

Last week, PLoS ONE, an online journal of the Public Library of Science, published a study called Order in Spontaneous Behavior, by Alexander Maye of the University of Hamburg, Chih-hao Hsieh and George Sugihara of the University of California at San Diego and Bjorn Brembs of the Free University of Berlin.

They observed the flight paths of fruit flies, especially in an all-white environment without any visual cues. Their purpose was to test the prevailing determinism in neuroscience that portrays the brains of all animals, including ours, as mere "input/output devices." The whiteness was designed to minimize the input. The output was the flight patterns, and specifically manoeuvres called "torque spikes." The scientists measured and analyzed the time intervals between these spikes.

Randomness has mathematical characteristics, "much like the hiss of static from a radio between stations," says the study. The "inter-spike intervals" (ISIs) were not random, according to a number of the authors' tests, but then again these ISIs could not be predicted, so the flies were judged to be behaving spontaneously.

The authors conjecture that there is an evolutionary advantage to being unpredictable, in being able to escape a predator or (for a female fruit fly) an undesirable male. They hope to go on to identify the brain circuits that permit this non-random spontaneity.

Though the paper discusses determinism and indeterminacy, it cautiously avoids the phrase "free will," with all its immense moral and metaphysical weight. The authors have spoken more boldly in interviews. Brembs has fairly summed up the study's implications, saying, "So if there is free will, it must be somewhere between chance and necessity -- which is exactly where fly behaviour comes to lie." In other words, he imagines a kind of range or spectrum, with points along a continuous line with two extremes.

As quoted by Roger Highfield of The Daily Telegraph, Brembs gets to an issue that speaks vividly to most of us: "A murderer can usually be made responsible for his crimes because he only rarely would be left without an alternative. The people claiming that free will doesn't exist say that one day we will be able show exactly why a murderer must necessarily have acted the way he did, by looking closely at his brain. We can show that you cannot even do this in fly brains, as a matter of principle."

The study's authors never define "spontaneity," though they link it with certain fractal, non-linear mathematical structures.

Leibniz tried rather harder in the 1600s to articulate this, though not altogether successfully:

"Liberty is spontaneity joined to intelligence. Thus what is called spontaneity in beasts, and in other substances destitute of intelligence, is raised in man to a higher degree of perfection." In one of his best-known works, his Theodicy (a title that means "justification of God"!), he said that spontaneity is the "body and basis" of freedom, an arresting phrase that is hard to interpret.

Leibniz's "beasts" would naturally include the fruit flies of Professors Maye, Hsieh, Sugihara and Brembs, but they also hold some hope for free-will robots to serve human beings and possible treatments of human psychoses.

I don't know nearly enough mathematics to assess their study, but at any rate their Darwinian explanation for spontaneity, and maybe for freedom, does not seem to me contradictory. The attribution of a cause to a general ability to choose freely does not have to trap us in the labyrinthine perplexities of whether a specific free choice can still be free if it has been caused by something else.

In a more down-to-earth way, the fruit flies' torque spikes can remind us of an old proverb, "Expect the unexpected." If these flies are naturally fitted to evade their hungry or lustful pursuers, they may teach us that what we call our freedom has much to do with our power to surprise one another.