Daily Archives: March 25, 2021

Free Will has lost all meaning

A headline got me going and the summary got me laughing, “Even worms have free will.” ScienceDaily has the item (here) on a paper about reactions of a worm to odors (A. Gordus, N. Pokala, S. Levy, S. Flavell, C. Bargmann; Feedback from Network States Generates Variability in a Probabilistic Olfactory Circuit; Cell, 2015)

This is not just any worm that has free will, it is C. elegans, a microscopic worm whose brain is completely known, all 302 neurons and their few thousand connecting synapses. Each neuron has a name and has been individually studied. Most of the little networks in the tiny brain have been studied to some extent. What can they mean when they say that C.elegans has free will? “If offered a delicious smell, for example, a roundworm will usually stop its wandering to investigate the source, but sometimes it won’t. Just as with humans, the same stimulus does not always provoke the same response, even from the same individual.

So it appears that free will can be ascribed to anything that is not completely predictable. Until, that is, it is understood enough to be predictable. But no, it does not even have to be unpredictable. They appear to have an understanding of the little 3 neuron web that controls whether the worm stops at an odor. “We found that the collective state of the three neurons at the exact moment an odor arrives determines the likelihood that the worm will move toward the smell.” So it appears that anything that can do more than a single thing when triggered with a particular stimulation, has free will. I think that would include all living things and a good many inanimate things too. Weather seems to fit the bill.

I hate to be pedantic but why use the phrase ‘free will’ with a meaning that is not remotely related to its philosophical meaning or its legal meaning. It either means that a choice is made outside the brain in some spiritual mind or it means that a choice was made consciously and carries attached responsibility. It should not be reduced to a meaning like: a worm will stop for a smell or go on depending on the state of 3 of its neurons. If sensory information is going to have only one effect on motor action, we do not need a brain at all; the sensory neurons can connect directly with the motor neurons with no need for other neurons in between. C. elegans may have a very small brain but it is a brain and it’s function is to nuance behavior – not a surprise when it does.

Here is the abstract, unlike the press release, it is very reasonable and does not mention free will:

Variability is a prominent feature of behavior and is an active element of certain behavioral strategies. To understand how neuronal circuits control variability, we examined the propagation of sensory information in a chemotaxis circuit of C. elegans where discrete sensory inputs can drive a probabilistic behavioral response. Olfactory neurons respond to odor stimuli with rapid and reliable changes in activity, but downstream AIB interneurons respond with a probabilistic delay. The interneuron response to odor depends on the collective activity of multiple neurons—AIB, RIM, and AVA—when the odor stimulus arrives. Certain activity states of the network correlate with reliable responses to odor stimuli. Artificially generating these activity states by modifying neuronal activity increases the reliability of odor responses in interneurons and the reliability of the behavioral response to odor. The integration of sensory information with network states may represent a general mechanism for generating variability in behavior.