20 12 10 - 13:09
What has been long established is that "deterministic behaviour" - the idea that an animal poked in just such a way will react with the same response every time - is not a complete description of behaviour.
"Even the simple animals are not the predictable automatons that they are often portrayed to be," Dr Brembs told BBC News.
However, the absence of determinism does not suggest completely random behaviour either.
Experiments including Dr Brembs' own 2007 work with flies has shown that although animal behaviour can be unpredictable, responses do seem to come from a fixed list of options.
"Free will is not that lofty metaphysical thing that it was until the 1970s or so," Dr Brembs said.
"More and more people are realising that it's a biological property, a trait; the brain possesses the freedom to generate behaviours and options on its own." - BBC
Much of this is simply adaptive: there are very few rational options, so you pick one based on a number of factors.
I don't think "free will" makes much sense anyway as a term. Do they mean choice? Choice without reactivity? Certainly that's possible; video game AIs do it all the time. It's a calculation.