15 ms·
Slime molds’ complex ability to detect mass from a distance
- trueman3 5y agonice, impossible to know!
- loa_in_ 5y agoGlass disks could reflect light towards the mold. Otherwise this experiment results seem contradictory to physics.
- newsbinator 5y ago> Then, the scientists turned out the lights and watched
- loa_in_ 5y ago> and watched They weren't touching, tasting, smelling or hearing.
- deleted 5y ago[deleted]
- newsbinator 5y ago> They keep time: if blown with cold air on the first of every hour, by the third hour, they’ll retract just before the cold snap.
- smegcicle 5y agoLooks like they chilled it three times, then just watched for a few hours, then chilled it again just to prank it https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/33004/1/PhysRevLett_100_018101.pdf https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/3300...
- Jensson 5y agoThat is super quick learning! And for a formless blob! Imagine if we knew how to train ML models that could reliably perform feats like this (learn after training, not train to withdraw every hour), while still managing all other parts of being a slime mold like hunting for food, distributing nutrients etc.
- voldacar 5y agoPhysical slime molds have already been used in an experimental model to optimize road networks: https://www.sciencedirect.com/science/article/abs/pii/S0303264711000608 https://www.sciencedirect.com/science/article/abs/pii/S03032...
- otabdeveloper4 5y agoThat won't happen for a long time. First we'd need to let go of the idea that "intelligence" means "neural network", and there's a huge amount of ideological resistance to the idea that intelligence isn't made with composeable atomic computation blocks.
- krisoft 5y ago> Imagine if we knew how to train ML models that could reliably perform feats like this I imagined it and I don’t find it that special. Picking up a strong and regular periodic signal and predicting the next iteration is not a hard problem. > while still managing all other parts of being a slime mold like hunting for food, distributing nutrients etc. ML models don’t do those things because ML models are abstract constructs without appendages or any other physical embodiment. We cannot manufacture artifical slime molds because we cannot manufacture artifical cells. This doesn’t seems to be an ML problem. (Or if it is, then everything become an ML problem too and the term lost its meaning.)
- Jensson 5y ago> ML models don’t do those things because ML models are abstract constructs without appendages or any other physical embodiment. I am talking about it doing this in a simulation. We don't have AI that are as smart as a slime mold at the moment, it will be an achievement when we get there. Also we can't discount the processing power required to process raw signals detected, our AI models needs to also learn the signal processing as well. The raw data a slime mold has to work with is extremely bare, if you get that input do you really think an AI could do the same things as it? And this is a single cell organism, this is the capability of a single biological cell. > Picking up a strong and regular periodic signal and predicting the next iteration is not a hard problem. Not if that is the only thing you do, no, but if you also do a lot of other things at the same time then it gets extremely hard. Edit: For example, how does the mold know that it just didn't move into a sunny spot? Or maybe this is just a cloud and it retracted unnecessarily? There are a lot of things to account for in a real world scenario that the slime mold has to understand that your naive signal processor can just ignore.
- rthomas6 5y agoCould it be because the three glass disks cause a slope in the agar gel? And the slime mold prefers to grow downhill?
- Darkphibre 5y ago> They found that, even more than the total mass of the objects, the slime mold reacted to how much of the horizon the objects occupied. It repeatedly preferred objects spread along the horizon as opposed to those at a single, stacked point
- richardfey 5y agoI wonder if it has something to do with surface tension
- kseistrup 5y agoOr could evaporation happen faster on the one-disk side so that the slime mold prefers to move towards the more humid/moist side?
- 123pie123 5y agoCould the slime grow thin extremely small exploratory network first and then decide how to grow its main body?
- LegitShady 5y agoHow many times was this repeated? How many trials did they have to do before they got this result? How many other objects did they try to see if its something related to the glass?
- Jensson 5y ago> How many times was this repeated? A 100 times for each variant. > How many trials did they have to do before they got this result? Looks like it picked the side with 3 disks 70% of the time and never picked the side with 1 disk. They tested a ton of different scenarios so the results seems really robust. "When presented with the 3-discs versus 1-disc choice, the Physarum grew toward the 3 disc regions 70% of the time, while never choosing the 1 disc region alone."
- bryan0 5y ago> In much the same way that a blindfolded person on a trampoline can sense if other people are on it, TRP channels help the slime mold detect faraway objects. This is as detailed a description as the article gives in how they detect objects? This explanation does not seem very helpful since I assume the glass disks were not jumping up and down. Is there any more information available on how they sense?
- 19f191ty 5y agoSensation of mechanical stimulation. How we sense touch, vibrations, sound.
- pphysch 5y agoThe experiment happened over a day, so lots of time for environmental vibrations (sound, seismic activity) to paint a subtle picture of the immediate surroundings.
- incompatible 5y agoThe original paper seems to be at https://onlinelibrary.wiley.com/doi/10.1002/adma.202008161 https://onlinelibrary.wiley.com/doi/10.1002/adma.202008161. I only glanced at it, but noticed that they hypothesized that the organism uses mechanosensation involving rhythmic pulling on the substrate and interpretation of changes in things like tension, compression or mechanical strain.
- adrian_b 5y agoFree access to the (preprint) paper appears to be at: https://www.researchgate.net/publication/340090261_Mechanosensation_Mediates_Long-Range_Spatial_Decision-Making_in_an_Aneural_Organism https://www.researchgate.net/publication/340090261_Mechanose...
- mcculley 5y agoIs there any reason one should not just go to Sci-Hub when hitting a paywall?
- captn3m0 5y agoI’m curious whether this result contradicts prior findings by making the experimental setups untrustworthy. If Slime can detect a mass horizon gradient, maybe experiments need to be redesigned to account for it?
- Tempest1981 5y agoNova has a show on this too: https://www.kpbs.org/news/arts-culture/2020/09/15/nova-secret-mind-slime https://www.kpbs.org/news/arts-culture/2020/09/15/nova-secre...
- SavantIdiot 5y agoSlime molds have three distinct phases. One phase is basically a distributed network of cells that communicate chemically. These signals can indicate when it is time to change form (transform!). Sounds like this is an extension of that in-between form. There is a fantastic book that talks about this kind of emergent intelligence in slime molds, called--ironically--"Emergence: The Connected Lives of Ants, Brains, Cities, and Software". The first 1/4 of the book is about the freakiness of slime mold. I thoroughly enjoyed this book, very well written and accessible and covers multiple domains (a lot like G.E.B.); Link to non-amazon: https://www.barnesandnoble.com/w/emergence-steven-johnson/1116788659?ean=9780684868769 https://www.barnesandnoble.com/w/emergence-steven-johnson/11...
- HABytes 5y agoTwang Ching-Shih might have cursed slime molds as nothing more than “demon droppings,” but this research on slime mold highlights how previous understandings of cognition may have been too in-the-box, constrained to familiar forms. “Cognition is all around you. It really is everywhere,” says Levin. “And really, it’s not just for furry, brainy things.”
- anotheryou 5y agoReminds me of the theory that many plants have "eyes". https://www.scientificamerican.com/article/veggies-with-vision-do-plants-see-the-world-around-them/ https://www.scientificamerican.com/article/veggies-with-visi... https://www.nationalgeographic.com/science/article/the-sneaky-life-of-the-worlds-most-mysterious-plant https://www.nationalgeographic.com/science/article/the-sneak... (for this there is the claim that it copies plastic plants, too. couldn't find anything factual though)
- jcims 5y ago>Object mass wasn’t the only factor the slime mold considered. When the three disks were stacked on top of each other instead of next to each other, the Physarum no longer preferred that side. It grew toward the three-disk and one-disk sides at about the same rate, despite their clear differences in mass. This, Novak says, “was a huge hint, or more like a slap in the face, that it must be basing its decisions on something else, too.” It's not clear to me if they are using 'mass' as we understand it from physics, or just the general notion of size of an object. To me the stacking experiment seems to invalidate that its the former. It would probably be useful to do some analysis on airflow inside the petri dish, there could be a very subtle convection and/or radiant heating from the white disks. There's also potential phototropic effects like we would see with plants bending towards light. Both of these inputs would actually be affected by the stacking, where mass is clearly not. (Yes they 'turn off the lights', but you can't take a time lapse movie in absolute darkness) Regardless of the cause, the effects are going to be extremely subtle, and the fact that the slime mold seems to select a direction based on this incredibly subtle effect is still extremely cool.
- Jensson 5y agoAlso it is really cool that it prefers to move towards objects with shapes, it prefers moving towards them over the clean walls and it prefers them more when there are more of those shapes. And the movement is very deliberate, it doesn't just meander in that direction but instead just heads straight to it.
- jcims 5y agoOh yeah, it definitely picked a direction and committed.
- Luc 5y agoSurely mass is a red herring in all this. The masses involved must be waaaaaay too small to detect, especially in the presence of earth's gravity. Why would a slime mold even evolve this capability of detecting tiny mass differences? None of it makes sense. It's much more likely there's an ultra-thin tendril they haven't noticed.
- Pigalowda 5y agoThere’s a lot of conjecture in this thread so I might as well throw in a couple cents. Mold is saprophytic so it’s more often than not advantageous to grow toward larger stationary objects in its environment to eat. The stack of discs deformed the agar gel, the mechanoreceptors on the periphery hyphae detected the tiny deformation and set off a chemical cascade for growth in that direction. What if the substrate is lumpy and harder than agar? The researchers disabled the mechanoreceptors and there was no “mass detection”. If there’s no deformation in the substrate by discs on a hard bumpy surface then I’m guessing those mechanoreceptors won’t detect the mass. So mold uses gradient deformation of mechanoreceptors to move toward possible food sources.
- geoduck14 5y ago>So mold uses gradient deformation of mechanoreceptors to move toward possible food sources. This explains why they compared the ability to a blind folded person on a trampoline. I wish they had explained it this way.
- Pigalowda 5y agoIt’s just my 2 cents. The mold may not even be moving toward a food source - it could be moving toward the deformation because larger objects cast bigger shadows and it needs to prevent desiccation.