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Organism without a brain creates external memories for navigation (arstechnica.com)
112 points by kqr2 on Oct 9, 2012 | hide | past | favorite | 30 comments



Here is an interesting video from BBC on how slime mold recreates the tokyo railroad plan and solves mazes - http://www.youtube.com/watch?v=sNAxrpzc6ws&feature=playe...


A great... and totally revolting documentary. I'm equal parts fascinated and queasy watching this. (edit: i mean all the way through)


That was a great documentary. Thanks for the link!


The mechanism described in the article, that slime mold uses slime to mark an area as it is exploring it to avoid exploring it again on a later pass, eerily reminds me of graph traversal algorithms.


http://news.ycombinator.com/item?id=3970427 Using A Slime-Mold To Calculate Minimum Spanning Trees


This article researches robots that explore unknown graphs and can place pebbles to distinguish nodes: "The Power of a Pebble: Exploring and Mapping Directed Graphs (1998)" by Michael A. Bender , Antonio Fernandez , Dana Ron , Amit Sahai , Salil Vadhan http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.19.2...


I'm not exactly sure how to phrase this question:

Are there any / what are the best examples of concurrent evolution of intelligence? What do we know about

For example, I know that Cephalopods like octopi seem to have developed a high level of intelligence despite being far removed (>500m years) from other known intelligent animals (mostly vertebrates). This shows us how a less centralized nervous system can produce "intelligence".

What do we know out the origins/early appearances of things like memory, reflexes, instincts…? Was it something like this slime stuff? Are there multiple implementations out there? Are they fundamentally limited or did our just happen to "advance" the most.


One of these crawled out of our compost bucket through the foam filter and onto the ground. It took about three days and the slime trail would dry over time so it really moved. I was fascinated and a little unnerved by it. It looked intelligent yet able to separate and reform.


tl;dr: it's a slime mold which avoids spreading where it has already spread (which are 'slimed' - a chemical marker, at the very least).

That might be stretching "external memories" a bit far, for hype's sake. Not that slime molds aren't fascinating, but what's with the hyperbolic word choices?


I think "external memories" is a reasonable term for this. If you treat it as an analogue to the computer science definition of memory - a place to store information - then it's a pretty decent way of describing what's happening here.

I suppose the fact that the information is being stored at the location it describes, instead of in a central location, makes it a bit weird?


I suppose the fact that the information is being stored at the location it describes, instead of in a central location, makes it a bit weird?

"weird" is emotional response. I think that function is the appropriate criteria here. Functionally, it is serving as memory. There's no magic difference between inside the body and outside of it.

Richard Dawkins' The Extended Phenotype http://www.amazon.com/Extended-Phenotype-Reach-Popular-Scien... is a good read on this sort of stuff (it's a little bit more technical than his other books, but still readable by someone without a biology background).


I'd be willing to bet the mold grows generally away from the most-dense areas (say, the interior of a glob). This makes sense energy wise - would you also call that "remembering" where it was?

Similarly, many plants "lean" to point towards the sun. Are they "remembering" where the sun is with the increased growth on the far side?

You can (successfully) argue that it can be an accurate description. It is. I would argue that it's deliberately choosing words that invoke more interest (be it scientific or "OMGWHAT") than accuracy.


> Similarly, many plants "lean" to point towards the sun. Are they "remembering" where the sun is with the increased growth on the far side?

If they had put the sun there first, then yeah, that would be external memory. That's the difference.


No, plants which do this generally grow less on the sunny side of their stalk. They are putting more / larger cells on the far side, as a form of memory. A crude counting system, if you will - when side A > side B, side B is where the sun is. Arguably this is even more complex than a mere external memory system - it deals in continuous ratios, rather than booleans!


Hmm. If you're just talking about the extra growth, then that's not even external. I don't think it's a good example.


Not of an external memory system, no. This would be internal. But would you call it "an internal memory system", or "decreased growth in reaction to sunlight"?

Another option: (micro-)evolution. Is an amoeba's resistance to a chemical "memory", or an environment-selected random mutation? Again, technically it can be viewed as memory, but it's diluting the term so far as to make it a catch-all for any kind of information, ever, to get someone to click on a link.


> But would you call it "an internal memory system"

Well, it's not being used later on to make decisions, is it?

I suppose I will go with that for my definition of memory: the agent makes a change to the state of the world (external) or to its own state (internal) and that change later affects its action.

Using that definition, my answer re the amoeba is yes.

I can see why it seems too broad. But I don't know a better definition. I suppose one could stipulate that consciousness is required. But I don't think that would be a standard position.


>Well, it's not being used later on to make decisions, is it?

No, you have a point there. I missed that part. Though I just realized your new definition implies this: a river has memory.

To each their own :) I'll still call it too broad, but that's pure opinion.


> a river has memory

Nice point... well, I'm all ears for a better definition :)


How does one slime mold react to the 'slime' left by another?


Unless the slime the researchers planted was from the slime-mold being experimented upon we can assume that they react in the same way to other slime-mold's slime as to their own.


Can they really be said to be 'memories' then?

I doubt that most people would consider Hansel and Gretel's trail of breadcrumbs a form of 'external memory.'


Could you elaborate on what an 'external memory' would be then?


I think it's only a matter of time before we prove slime-molds to be turing-complete.



I can't wait to read a sci-fi story about advanced and perhaps sentient slime molds taking over the universe.



Steven Baxter's Xeelee Sequence comes to mind.


This is more or less how I find my way around in the morning. The only major difference is that I generally use coffee-spills and biscuits as location markers, instead of slime.


Organism without a brain creates external memories for navigation

A manager downloaded a TODO list app?




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