"Plants appear to 'think', according to US researchers, who say that green plants engage in a form of problem-solving computation.
David Peak and co-workers at Utah State University in Logan say that plants may regulate their uptake and loss of gases by 'distributed computation' - a kind of information processing that involves communication between many interacting units.
It's the same form of maths that is widely thought to regulate how ants forage. The signals that each ant sends out to other ants, by laying down chemical trails for example, enable the ant community as a whole to find the most abundant food sources...."
More correctly the plants "compute", though the distinction between "thinking" and "computing" is a subtle one, having much to do with what consciousness is (if it exists at all).
The theme of computation as an emergent behavior arising from the interaction of many systems capable of maintaining stateful information is very hot now. E O Wilson popularized this in entomology. The more we look at biology, the more we see computation. I was struck the other day, for example, how a red striped shirt seemed to have a JPEG artifact. Problem is, I was looking at the shirt, not at a compressed digital photo of the shirt. I expect that somewhere in our visual, sensory and perceptual cortices something rather like JPEG compression is occurring.
The next set of articles will be about computation across species (symbiotes, parasites) and ecosystems -- producing emergent behaviors. Does an ecosystem have the processing capability of a rat?
The Gaia cultists must be having a good laugh!
Of course where else do we have lots of connected entities each of which holds stateful information? We have it in economies, and across the Internet. Of course these stateful entities appear to be independently conscious humans, but recent research strongly suggests that emergent computation is occuring. One day perhaps we'll measure the IQ of that emergent entity ... or it will measure ours ... :-).