Free will and true spontaneity exist in fruit flies. This is what scientists report in a groundbreaking study in the May 16, 2007 issue of the open-access journal PLoS ONE.
"Animals and especially insects are usually seen as complex robots which only respond to external stimuli," says senior author Bjrn Brembs from the Free University Berlin. They are assumed to be input-output devices. "When scientists observe animals responding differently even to the same external stimuli, they attribute this variability to random errors in a complex brain." Using a combination of automated behavior recording and sophisticated mathematical analyses, the international team of researchers showed for the first time that such variability cannot be due to simple random events but is generated spontaneously and non-randomly by the brain. These results caught computer scientist and lead author Alexander Maye from the University of Hamburg by surprise: "I would have never guessed that simple flies who otherwise keep bouncing off the same window have the capacity for nonrandom spontaneity if given the chance."
The researchers tethered fruit flies (Drosophila melanogaster) in completely uniform white surroundings and recorded their turning behavior. In this setup, the flies do not receive any visual cues from the environment and since they are fixed in space, their turning attempts have no effect. Thus lacking any input, their behavior should resemble random noise, similar to a radio tuned between stations. However, the analysis showed that the temporal structure of fly behavior is very different from random noise. The researchers then tested a plethora of increasingly complex random computer models, all of which failed to adequately model fly behavior.
Only after the team analyzed the fly behavior with methods developed by co-authors George Sugihara and Chih-hao Hsieh from the Scripps Institution of Oceanography at UC San Diego did they realize the origin of the fly'
Contact: Bjrn Brembs
Public Library of Science