Single-Celled Organism Appears to Make Decisions (2019)
the-scientist.com
the-scientist.com
“This paper nicely settles a debate between those [researchers] willing to accept that non-neuronal organisms are also capable of processing information and acting on that information, and those that stick to the idea that only neuronal organisms are capable of complex decision making,” Madeleine Beekman, an evolutionary ecologist at the University of Sydney who was not involved in the study, writes in an email to The Scientist. “Clearly there is a fundamental difference between brained and brainless organisms,” she continues, “[b]ut the point is that a brain did not come out of nothing. The brain is the result of selection pressure placed on organisms with the most basic form of information processing. Gunawardena and colleagues show that this basic ground work is already present in unicellular organisms.”
I don't know who Dr. Beekman has been debating with, but, at best, this has only been a debate of semantics for at least 50 years.
Here is an excerpt from a review titled Bacterial Microprocessing (Cold Spring Harb Symp Quant Biol. 1990;55:539-45. doi: 10.1101/sqb.1990.055.01.052.). The review is from 1990, but the work goes back at least to the late 1960s.
To someone trying to understand the brain, the bacterium Escherichia coli must be an awesome beast. Its talents are legion, but its size is miniscule. E. coli is a cylindrical organism less than 1 μm in diameter by 2/μm long--20 would fit end-to-end in a single rod cell of the human retina or some 3000 in that of a frog. Yet, it is adept at counting molecules of specific sugars, amino acids, or dipeptides; at integration of similar or dissimilar sensory inputs over space and time; at comparing counts taken over the recent and the not so recent past; at triggering an all-or-nothing response; at swimming in a viscous medium; and as we shall see, even at pattern formation.
At the 53rd Symposium, I presented an overview of sensory transduction in bacterial chemotaxis (Berg 1988), describing the kinds of measurements that E. coli makes on its surroundings and noting how this strategy matches the physical constraints imposed by small size in an aqueous environment (i.e., by life at low Reynolds number; see Purcell 1977). I will restate that case briefly, comment on progress made in the field during the past 2 years, and mention some of the work going on in my own laboratory.
Even in the Age of the Internet, being able to put your hands on the right review paper is not given at all
My girlfriend and I both have mental health issues and that is most of my saw in wanting to understand Neuro 101 or comparative animal neuro or Evolutionary Neuro or anything that will incrementally add to an understanding of human brains that will improve the ability to advocate for ourselves in the US health care system.
Serendipitously, I was independent studying on fluid mechanics and dynamics last year[0] and had been through Purcell 1977, so I'm excited to check out your work on that account as well!
[0] There are some nice YouTube videos out there to ramp you up to understanding Purcell 1977 better as a layman with undergrad maths
Numberphile -- Reynolds Number
This specializes the regular nucleus for reproduction, while the macronucleus becomes a sort of brain, using DNA as an information processing and storage engine?
It calls attention to the brain-like activity of the regular nucleus in cells that don't have a macronucleus, and of the raw DNA in a bacterium.
'Makes a suprisingly sophisticated series of decisions' is more supportable. But whether you are surprised depends on your intuition about how complex a tiny machine with feedback from sensors and quite a lot of internal state can be. Since almost every biological system I've ever learned anything about is mind-bogglingly rich with complex dynamics, my default is to be unsurprised by rich externally-observable behavior.
Well yes, that's the point. They found that prospective control goes faaaaaaaaaar back in evolutionary history.
This implies memory. Venus fly traps use calcium gradients for short-term memory [1]. It would be interesting to learn how this organism remembers.
[1] https://www.sciencenews.org/article/how-venus-flytraps-store...
Shouldn't be too surprising.
"In genetics, a promoter is a sequence of DNA to which proteins bind that initiate transcription of a single RNA from the DNA downstream of it. This RNA may encode a protein, or can have a function in and of itself, such as tRNA, mRNA, or rRNA. Promoters are located near the transcription start sites of genes, upstream on the DNA (towards the 5' region of the sense strand)."
In programming terminology, the promoter region listens for events, and is followed by a handler body. So protein concentrations can be used for state.
Regarding the calcium gradients you mentioned, I wonder... I think they are more about inter-cellular communication. Cells can use calcium to make electricity. Calcium is also used by neurons to send electric pulses.
I actually find it fascinating that neurons are not unique in using electricity to communicate - that an analog exists in the plant world.
[0] you'd have to inject non-determinism as well.
We are far from knowing whether this is the case. So you can believe one extreme or the other (or something in between), but either way it's an article of faith, not an established fact.
If so, you're bringing in something that's purely a matter of faith as no evidence has ever been found of a soul (AFAIK).
If no soul then be it single-celled or human, we're back in the mechanistic world and one is, somehow, just a more elaborate version of the other.
Some people believe that when the machine becomes sufficiently complex, consciousness will emerge. Others don't. Either way, it's a matter of faith.
> We have no more evidence...arises from the operation of a purely mechanistic state machine than we have for the existence of a soul.
Evidence of a soul: 0%. Evidence of atoms: 99.999999999999999999% or higher.
(Who said anything about atoms? I didn't.)
Couldn't agree more, but that wasn't your original assertion, to wit first para of https://news.ycombinator.com/item?id=24962220
> Who said anything about atoms? I didn't.
You: "...from the operation of a purely mechanistic state machine" So what's a 'purely mechanistic state machine' going to be made of if not atoms.
https://news.ycombinator.com/newsguidelines.html
Note this one in particular:
Please respond to the strongest plausible interpretation
of what someone says, not a weaker one that's easier
to criticize. Assume good faith.
The fact that we don't know what consciousness is doesn't mean we can't make reasonable guesses. Now, given that we understand both macroscopic and microscopic physics pretty well these days, there is only so much room for guessing and some guesses are much more reasonable than others.
Ultimately, "you do you" is as much resolution as can reasonably be expected, down such a rabbithole.
You can simulate that with a state machine, but only with one that is much more complicated. Nature doesn't exactly prefer simplicity, but it's very bad at discovering solutions that need a big jump in complexity compared to a previous generation.
We all began as single cells (zygotes) and somewhere along the way we suddenly became conscious, whereas a moment before, we were not conscious. What was that point in time?
You may not have realized it, but many would debate the assumptions in that sentence. ^_^
Sidestepping a decent into the definition of 'conscious' itself for now, one could propose that consciousness is an inherent nature of matter itself, and it just emerges further/grows in complexity as the zygote develops.
Ultimately, nobody has determined a practical need for a definition, or really for the word, outside of discussion of people in comas, so reasonable people let it go.
You never 'become' conscious, you adapt and interact with the environment from the first cell.
To Fix the Reproducibility Crisis, Rethink How We Do Experiments
https://blogs.scientificamerican.com/observations/to-fix-the...
The paper also includes dozens of trials replicating the results across organisms.
Evidence of volition and decision making in this form simplifies the challenge of understanding "consciousness".
Not much. The organism is expressing a preference for staying alive. That is a default preference for life.
The question of volition only emerges with higher preferences or ones at odds with survival.
The cell is a mechanism tested and refined by evolution. It's purpose is to sustain itself, adapt to the environmental aggressions and self replicate. Its volition is the best strategy nature could find to keep it alive.
Are not single celled organisms as "conscious" as multi-celled organisms? Or, alternatively, are multi-celled organisms not as non-"conscious" as single celled organisms?
What organism/s experience it?