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by AQuantized 732 days ago
There's an idea of 'fixed action patterns' where certain behaviors are encoded in the neurology of an animal, and triggered by certain stimulus.

For spiders then there is an action pattern that upon certain stimulus they will use their spinnerets begin forming a web, first placing anchor points and gradually building it up with radial threads and spiral. The exact behavior differs by species such that they have different resulting patterns. It seems possible that there is an element of 'learning' beyond the basic pattern as well, even in seemingly very simple animals.

I doubt the spiders have a mental model of what their web looks like as such, it's more evolutionary driven genetic behavior, a particular neuronal pattern encoding the action sequence rather than an underlying fundamental understanding.

3 comments

Thanks!

>For spiders then there is an action pattern that upon certain stimulus they will use their spinnerets begin forming a web, first placing anchor points and gradually building it up with radial threads and spiral.

I can sorta understand stimulus causing them to start making a web (sorta like stimulating a mammary can cause lactation) - but how do it 'know' to use a radial pattern rather then ah-hoc mess the black widows on my porch make? The 'ad-hoc' pattern seems like it would be more 'likely' then a nice pattern? Overall, I guess it just seems like a rather complex pattern/behavior?

Also, I guess I have a more basic question of 'what is instinct' if its not some sort of 'memory'? People seem to have an 'instinct' of the mechanics of throwing a ball, yet we have wildly different abilities with regards to accuracy, 'form', distance/speed (due to muscalture?) - it just seems like we have an 'instinct' for the 'simple' mechanical movements but not for the more complex behavior like throwing a ball to hit a target ?

Thanks again!

You can basically think of insects like this as organic ASICs. Input in, output out. It's a biological circuit that just has a raw response that's hardcoded in. Kind of like asking how does a computer know to do "MOV". It's baked in to the circuit. Do trial and error trillions of times and some of the circuits end up functioning and survive.
It just seems like a lot of behaviors are closer to full blown programs rather than a single instruction :-)

And the more complex the behavior the more it blows my mind :-D

Thanks!

Thanks for the link below - it was pretty neat :-D

Yeah, the depth of biology is insane. You can even look closer to home - humans have built in visual mappings for specific shapes. https://www.quantamagazine.org/a-math-theory-for-why-people-...
The stimulus starts the fixed action pattern, but that action pattern includes the behavior to make the entire web, not just the start off the process. Different species of spider have different fixed action patterns (and different neurology underlying that, and different DNA underlying that neurology).

I think throwing a ball is more learned, although some behaviors like grasping the ball may provided a fixed action foundation on which higher order learning builds. Baby humans have a grasp reflex that works in a similar way to the fixed action pattern described, but with a simpler action sequence. If you touch the palm of a toddler, they will instinctively tightly grasp. It's interesting that the grasp reflex disappears around 5 years old, so the fixed neuronal pattern is subsumed by higher order learned behavior.

>>includes the behavior to make the entire web, not just the start off the process.

Thats where I get stuck..the 'behavior' has to account for different sizes of webs (the spider might be in a tight space, or a more open space), etc.

That just seems like an incredibly complex behavior to encode...Cells are supposedly 'simple' organisms but they manage to create/manage such complex behaviors...it's mind blowing..

Thanks!

It's been awhile, but I was reading about black widows. Apparently the better fed they are, the worse the web, so they don't over feed.

A chaotic web is a sign that the black widow spider is well fed and not hungry.

Huh...I didn't know that...the lil S.O.B.s on my porch must be really well fed - the webs are everywhere :-D

Thanks

I'm pretty sure it's generally 1 spider per web, and I thought blackwidows (assuming they are still alive) take down the webs when done. So presumably you have quite a few spiders.

In any case here's a discussion of said paper.

https://www.nationalgeographic.com/science/article/death-tra....

yeah - I guess it varies but I can usually spot about 5 of them out at night...Thanks for the link!
> I can sorta understand stimulus causing them to start making a web (sorta like stimulating a mammary can cause lactation) - but how do it 'know' to use a radial pattern rather then ah-hoc mess the black widows on my porch make? The 'ad-hoc' pattern seems like it would be more 'likely' then a nice pattern? Overall, I guess it just seems like a rather complex pattern/behavior?

My guess: It "just feels right".

In the beginning (?), the species didn't have any "preference" and just did whatever. Some species cut the pizza in circles (as in, cutting out a circle from inside the pizza, leaving a donut-shaped pizza), others cut squares, others cut weird shapes, etc. All over the place.

Over time, those predisposed to cutting the pizza in a straight line, from border to border, passing through the center, began to survive slightly longer than the rest (for some unknown reason), becoming the dominant predisposition. To anyone born since then, it just felt right to cut the pizza that way. Not passing through the center of the pizza was just weird. And stopping a cut midway, without going all the way through, was also just weird.

At that point the amount of cuts still varied though, so it was all over the place. Some cut it in half, other made 2 cuts (4 slices) but they were in ugly 20° angles (so 2 huge slices and 2 small slices), others made hundreds of cuts so each piece was tiny and was annoying to eat, stuff like that.

Over time, those who preferred to cut the pizza in 90° angles started to survive slightly longer, and over time became the dominant predisposition.

And so on and so on. With these learnings it was becoming easier for people to make pizza ("find food"). Pizza sizes increased, and so did the amount of people sharing a single pizza. Making it easier to attract others, and share a pizza with them. Meeting more people makes it slightly more likely to find a life partner.

Time passed, same old song and dance. Now all pieces must be symmetrical. It was the most fair way to share. Not doing it this way meant the one doing the cuts was evil and must be avoided.

Current situation: Most people cut the pizza in 8 equal-ish slices because it just feels right to do it that way. Those who don't do it that way might still reproduce, but are slightly more likely to be avoided because they are weirdos. They are also slightly less able to get food, because nobody wants to share their pizza with those weirdos, so they are slightly more likely to starve due to being unable to "attract" food.

In that parallel universe, someone named 224hcem asks:

> But how do they "know" to cut the pizza in 8 equal slices rather than the ad-hoc mess the teenagers next door make with their microwaved pizza? Overall it's way more effort to try to make all pieces nice and equal, and the movements have to be more precise meaning the brain calculations are more complex compared to just winging it.

I guess I just get hung up on how such 'simple' cells can encode such complex behaviors...

Thanks

Adjacent, and you've probably seen it before, but you and others might be interested: https://en.wikipedia.org/wiki/Effect_of_psychoactive_drugs_o...

This is fascinating stuff.

LOL - yeah, I remember seeing the spider ones and going "probably better then I could do stoned" :-P
I've always wondered why so many different culture know some notion of a dragon. Is it possible that these are based on inherited memories, patterns, insticts of dinosaurs? I know this would be a wild leap but one my wonder.
The trick is that "some notion of a dragon" is incredibly vague, with "dragons" sharing very few commonalities between cultures. A European wyvern and Quetzalcoatl are almost nothing alike, yet people consider them both "dragons."

>Is it possible that these are based on inherited memories, patterns, insticts of dinosaurs?

It is possible that these are based, at least in part, on the discovery of dinosaur fossils, but humans didn't even evolve until the dinosaurs were long dead. So even if it were possible for "inherited memory" to include visual memories it wouldn't do so for dinosaurs.

Why should inheritance stop at species boundaries?
It isn't a matter of "species boundaries," which aren't even really rigidly defined, so much as time, complexity and information compression.

It doesn't seem likely that whatever primitive mammalian ancestor eventually evolved into primates, and then into humans, carried within it a coherent enough visual and behavioral memory of dinosaurs to have survived so many generations of mutation, eventually informing the modern idea of "dragons" as winged reptiles.

And again, it isn't even true that there is a cross-cultural concept of "dragons" to begin with. It's a eurocentric myth, in that it assumes a Western concept of a "dragon" to be the default, and ignores any other cultural context in order to fit their mythologies into that mold.