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Flies That Do Calculus With Their Wings

samzenpus posted about 7 months ago | from the show-your-work dept.

Science 107

DudeTheMath (522264) writes "Cornell University scientists studied how fruit flies respond to flight disturbances (instead of wind gusts, they used carefully controlled magnetic pulses) and found that the flies recover in as little as three wing beats (at 250 per second) by doing some kind of calculus in a little 'integrated circuit' of neurons that control the wings directly. The pitch and yaw results are already published, and the roll study is forthcoming."

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It's hardwired (3, Informative)

invictusvoyd (3546069) | about 7 months ago | (#46541055)

Things implimented in hardware are always more efficient that those in software . For the fly it happens at such a low level that it is extremely efficient.

how calculus? (1)

globaljustin (574257) | about 7 months ago | (#46541131)

Can you or anyone explain how what the neurons are doing is "calculus"?

Do they mean that were humans to mimic the neurons in a simulation, we'd have to do calculus in an algorythm to achieve the desired result?

Re:how calculus? (5, Informative)

TurboStar (712836) | about 7 months ago | (#46541173)

Can you or anyone explain how what the neurons are doing is "calculus"?

Calculus is how we scientifically communicate nature to each other, not away for nature to implement mathematics. Flies are not doing calculus any more than you catching a thrown ball is doing calculus. This headline, and perhaps the grant proposal, is written for stupid people. I hope this explains it for you.

on a different note... (0)

globaljustin (574257) | about 7 months ago | (#46541387)

Calculus is how we scientifically communicate nature to each other, not away for nature to implement mathematics.

aren't we part of nature?

so Calculus is "not a way for nature to implement mathematics" but humans use it to communicate nature

does that mean you consider the act of abstraction "non-natural"?

Re:on a different note... (1)

StripedCow (776465) | about 7 months ago | (#46541873)

aren't we part of nature?

Yes. And so are flies.

Flies are made out of atoms.
So are we.

Atoms don't touch eachother.
There's no single sharp separating surface you can draw between the atoms of a fly and the atoms of a person.

Therefore, we ARE the flies.
And WE are doing the calculus.

Re:on a different note... (1)

hawkinspeter (831501) | about 7 months ago | (#46542281)

Woah Dude! It's like we're all part of the universe examining itself/ourselves from every angle.

another different note (1)

globaljustin (574257) | about 7 months ago | (#46544119)

yo hawkinspeter, can you or StripedCow explain why someone would mod my "on a different note..." post as "Troll"?

i genuinely don't understand the mod, and am honestly a bit more confused about Calculus than when I started

Re:another different note (1)

hawkinspeter (831501) | about 7 months ago | (#46544395)

Most likely because the mod thought you were wanting to start an argument. If I'd modded you, I'd have gone for Funny or possibly Off-topic depending on what mood I was in. I wouldn't consider your post a troll at all.

Re:another different note (1)

globaljustin (574257) | about 7 months ago | (#46545173)

word I was being serious about the "non-natural" thing...it's a whole other discussion, but it relates to cybernetics

if the act of "abstraction" really is a human-only trait of all life we observe in the universe that could mean something

i think it's probably just a big conversation leading to nowhere but maybe there will be a chance to discuss it in the future

Re:another different note (1)

AlphaWolf_HK (692722) | about 7 months ago | (#46546859)

Off topic, but you and I seem to have a mutual fan manifest by slashdot's disdain for serif fonts. Note these are two different URLs:

http://slashdot.org/~gIobaljus... [slashdot.org]

http://slashdot.org/~gIobaIjus... [slashdot.org]

This one will probably be taken soon:

http://slashdot.org/~globaIjus... [slashdot.org]

I mostly ignore him, but had to modify my signature to make the distinction clear when a few accusations were thrown my way, and I just happened to notice that he's up to it again a minute ago.

Re:another different note (1)

globaljustin (574257) | about 7 months ago | (#46548171)

thnx AlphaWolf_HK

I wonder who's up to this? And does /. know/care?

could this be APK in Beta???

Re:another different note (1)

globaljustin (574257) | about 7 months ago | (#46549009)

hey just wanted to add that I've been aware of my doppleganger for about 2 months now

it's weird...

I haven't changed my sig b/c i'm almost afraid that the dupe "globaljustin" will change theirs...

one of mine makes quasi-constructive comments and gets upmodded

i recently addressed one who **replied to one of my comments** and this is what happened: http://slashdot.org/comments.p... [slashdot.org]

he says, "please ignore the troll pretending to be me"

which i didn't reply to

Re:another different note (1)

AlphaWolf_HK (692722) | about 7 months ago | (#46550329)

Yep, he probably will change his to match yours. This is mainly because on slashdot, most people recognize other people by their signature rather than their name. If he doesn't copy your signature, most people won't ever mistake him for you, and he knows that. So, he did the same thing to me.

At first I just made a joke of it and kept changing my signature to say different goofy things, and just watched him copy it. After a while I stopped and created my current signature, which he never copied. (Though given that all of his accounts with my name have been banned it's kind of moot now.)

Re:how calculus? (1)

gl4ss (559668) | about 7 months ago | (#46541541)

you catching a ball is way, way more calculus.

this is more akin to analog circuit fly-straight autopilot doing calculus.

Re:how calculus? (2)

GrumpySteen (1250194) | about 7 months ago | (#46542327)

you catching a ball is way, way more calculus.

It really isn't. Catching a thrown ball requires practice, during which you learn more or less how a ball moves after being thrown without any actual understanding of the math behind it.

If you were doing calculus, you'd know exactly where the ball was going as soon as you saw it moving and you could simply put your hand in the right place and wait for the ball to arrive.

In reality, you get yourself into what looks like it might be the path the ball is going to take, then you constantly correct your position as the ball gets closer. It's more like a series of guesses where you're constantly told whether you're getting closer or further away from the correct answer and that is not calculus.

Re:how calculus? (1)

Jmc23 (2353706) | about 7 months ago | (#46542453)

It's more like a series of guesses where you're constantly told whether you're getting closer or further away from the correct answer and that is not calculus.

Perhaps you don't understand calculus?

One thing is for certain, you're not very good at catching balls. Some of us can tell exactly where it's going to land.

Re:how calculus? (0)

Anonymous Coward | about 7 months ago | (#46542783)

Perhaps you don't understand your own brain, and how it works?

Re:how calculus? (0)

Anonymous Coward | about 7 months ago | (#46543655)

He obviously doesn't understand calculus. Calculus is the study of rates of change over time. That's the basic definition that you get on day 1.

A thrown ball changes multiple positional variables over time, and at varying rates according to the environment. It has a position in space that changes in three dimensions, it has a velocity, it has mass that can be acted upon by outside forces (e.g. wind), and it has surface properties that can interfere with how those outside forces act upon its mass (stitching, laces, seams, various other properties of different types of balls). All of these can be mathematically modeled and assigned numeric values. But that's not necessary in order for the process of determining future values from present ones, which is the primary application for what calculus does.

From the thrower's release, your brain has likely already determined 1) approximately how much time before the ball reaches you, 2) how far the ball will travel unimpeded, 3) whether it will hit the ground in front of you or behind you, and 4) approximately where you need to be to intercept its path. In the next instant, you begin coordinated muscle movements based on those observations, which in itself requires more calculus to keep your balance and reposition yourself within your surroundings without causing yourself harm. As you set up to catch the ball, your brain goes into a feedback loop to fine-tune its calculations and your position. This loop is called a "P-I-D loop" in industrial programming applications, which stands for "Proportional-Integral-Derivative". The proportional, or linear, response causes rapid changes in response to both input and feedback. The integral response, puts the brakes on the proportional response to prevent overshoot. The derivative response fine-tunes the resulting calculation to allow exact positioning. At the time that the brain has already calculated, and at the position it hopefully has pushed the mechanical parts of the body to position itself in, the ball arrives and is "caught".

Just because there aren't numbers involved doesn't mean it isn't still math. Anyone who thinks that catching a ball (or any other process that involves human motion in a feedback loop, really) isn't calculus is wrong. And if they were right, they'd be dead, because they wouldn't have avoided a close call some time in their life.

Re:how calculus? (1)

GrumpySteen (1250194) | about 7 months ago | (#46545087)

Fom the thrower's release, your brain has likely already determined 1) approximately how much time before the ball reaches you

Calculus will tell you exactly how long it will take for a ball to get to you, not an approximate guess.

You've confused "being familiar with thrown balls so that you can make a good guess" with "actually doing math."

Re:how calculus? (1)

GrumpySteen (1250194) | about 7 months ago | (#46545137)

Some of us can tell exactly where it's going to land.

No, you can't. Calculus can tell you exactly how far the ball will travel down to the last millimeter if you account for all of the variables.

You can make an educated guess, but you'll completely fail to catch the ball if you then close your eyes and assume that it will be exactly where you predicted it to be. If you can tell exactly where is going to land, why would you need to see it and make corrections?

Only an idiot would believe that they can tell exactly where a ball is going to land from the instant they see it being thrown. And here you are claiming just that.

Re:how calculus? (1)

Jmc23 (2353706) | about 7 months ago | (#46547391)

Some of us can even juggle with our eyes closed.

You are aptly named, is it because you lack skills that you are so grumpy?

Re:how calculus? (1)

tomhath (637240) | about 7 months ago | (#46543973)

If you were doing calculus, you'd know exactly where the ball was going as soon as you saw it moving and you could simply put your hand in the right place and wait for the ball to arrive.

Really good outfielders can do that. Willie Mays would turn around and run straight to the spot where the ball would come down without watching it - as soon as it left the bat.

Re:how calculus? (1)

GrumpySteen (1250194) | about 7 months ago | (#46545057)

If they could do that, they wouldn't have to keep watching the ball as they ran and caught it. There's a reason they keep their eyes on the ball. Constant corrections.

Re:how calculus? (1)

X0563511 (793323) | about 7 months ago | (#46546193)

What's not calculus about that? You approximate the result and further refine it with additional data/time. With even more practice, you certainly CAN see where it's going to land (barring interference by another force, such as wind).

We are quite good at this. How do you think things like hitting moving targets with arrows happens?

Re:how calculus? (1)

GrumpySteen (1250194) | about 7 months ago | (#46546749)

Calculus is not a series of guesses. If you think it is, you should probably go back to school.

Re:how calculus? (1)

X0563511 (793323) | about 7 months ago | (#46546181)

So, the fly has a biological PID controller [wikipedia.org] ?

Re:how calculus? (0)

Anonymous Coward | about 7 months ago | (#46551581)

Actually, the PID controller was based on the experience of how helmsman control the course of ships, seminal papers on this are Sperry's (1922) and Minorsky's (1922). It's nothing but a *linear approximation* to how we react in the presence of error.

It's not accurate to say fruit flies have a biological PID controller, or any other type of human designed controllers for that matter.

Biological control is inherently non-linear and is, with our current technology, impossible to be precisely modeled or even understood.

Re:how calculus? (1)

Joce640k (829181) | about 7 months ago | (#46541927)

Calculus is how we scientifically communicate nature to each other, not away for nature to implement mathematics. Flies are not doing calculus any more than you catching a thrown ball is doing calculus. This headline, and perhaps the grant proposal, is written for stupid people. I hope this explains it for you.

When somebody throws a ball to you, how do you figure out how to catch it?

Mechanical/electrical systems can do calculus, stupid.

Re:how calculus? (0)

Anonymous Coward | about 7 months ago | (#46542983)

When somebody throws a ball to you, how do you figure out how to catch it?

You don't figure out how to catch it. A combination of neural networks in the spine and neutral networks in various levels of the brain, move your hands, and you catch it. The neural networks involved use something like a heuristic Bayesian learning procedure. At no stage in your life did your brain sit down, work through the calculus of ballistics in air, and figure out how to catch things.

Mechanical/electrical systems can do calculus, stupid.

Mathematica can do calculus but the kinds of systems you're talking about can't do calculus, stupid.

Re:how calculus? (0)

Anonymous Coward | about 7 months ago | (#46543109)

When somebody throws a ball to you, how do you figure out how to catch it?

I don't use calculus to figure it out. I just move my hands in such a way that they'll be in a position to catch it, based on where the ball is going. That's not necessarily calculus, not even unconsciously.

Re:how calculus? (0)

Anonymous Coward | about 7 months ago | (#46544501)

Throwing a ball is a very very stupid example since it has nothing in common with the article (well, nothing of any importance anyway). You should have said keeping your balance.

Re:how calculus? (1)

idji (984038) | about 7 months ago | (#46546537)

Calculus is summing lots of tiny inputs and making an output. Neurons sum a lot of tiny inputs and make an output.

Re:how calculus? (1)

50000BTU_barbecue (588132) | about 7 months ago | (#46542015)

There are quantities somewhere in there that represent rates of change of something.

Re:how calculus? (1)

DoctorBonzo (2646833) | about 7 months ago | (#46542095)

This is just the mass media's way of hyping something so it's likely to sound interesting to the general public so they can increase their ratings.

It almost always happens with reporting of pretty much anything scientific.

It should always sensitize your bullshit detector.

Err, not always (1)

Viol8 (599362) | about 7 months ago | (#46541617)

I'd like to see someone try and implement chess or a 3D game purely in hardwired TTL. It might be theoretically possible but I doubt it would be more efficient (ie faster , uses less energy) than software running on a processor.

Re:Err, not always (1)

invictusvoyd (3546069) | about 7 months ago | (#46541641)

yup but the fly wings seem like a good target for TTL

Re:Err, not always (1)

Viol8 (599362) | about 7 months ago | (#46542669)

IMO I think something like that would be better off implemented in analog hardware - you could virtually mimic the neurons 1 to 1 and it doesn't matter if a bit of noise gets in the system.

Re:Err, not always (1)

pushing-robot (1037830) | about 7 months ago | (#46543171)

TTL chess might be faster, since no game would last longer than 255 moves.

Interesting (5, Funny)

colinrichardday (768814) | about 7 months ago | (#46541057)

Any way of installing these wings on college students?

Re: Interesting (-1)

Anonymous Coward | about 7 months ago | (#46541083)

Or airplanes. Then maybe the passengers of the Malaysia flight would still be alive.

Re: Interesting (-1)

Anonymous Coward | about 7 months ago | (#46541177)

Why don't you fly on over to http://soylentnews.org/ [soylentnews.org]

Re: Interesting (1)

rossdee (243626) | about 7 months ago | (#46541803)

Bad weather was not a factor in that incident

Red Bull? (0)

Anonymous Coward | about 7 months ago | (#46543021)

gives you wings. EOM

So... (3, Funny)

fuzzyfuzzyfungus (1223518) | about 7 months ago | (#46541095)

Horrid little vermin, and the thing likely has a couple of brutally well optimized high speed analog PID controllers, all within its (very tight) payload limits, and all since before we were grunting and hitting one another with rocks. Thanks nature...

Re:So... (0)

Anonymous Coward | about 7 months ago | (#46551599)

There is no equivalence between the control mechanisms in biology and PID controllers.

Also, biological control is actually discrete instead of anolog. I'm not sure why people in this post are talking about analog computers since neurons behave discretely (hint: it's why they PULSE).

Finally, analog computers are a terrible analogy since they suffer from horrid precision. They are also sensitive to drift, component aging, temperature and a miriad of factors.

In other words.... (3, Insightful)

scottbomb (1290580) | about 7 months ago | (#46541125)

What the fly does naturally requires the use of calculus to mimick artificially. Seems pretty natural to me. The laws of physics and mathematics are inseperable.

Re:In other words.... (1)

X0563511 (793323) | about 7 months ago | (#46546241)

Calculus is not mimicry.

wow (0)

Anonymous Coward | about 7 months ago | (#46541137)

amazing progress in neurology!

Calculus? (4, Insightful)

AK Marc (707885) | about 7 months ago | (#46541147)

That's like saying that a dog catching a ball or frisbee is doing calculus. Nope, it's experience. Push me this hard, and I push back that hard. It goes that way about that fast, and I'll go this way. Turbulence pushes me here, I'll twitch back. That doesn't mean calculus, that just means quick feedback.

A human-built bug might have to do the calculus, but the natural bugs don't.

Re:Calculus? (4, Insightful)

stox (131684) | about 7 months ago | (#46541457)

Actually, it is doing calculus with a highly optimized analog computer. Amazing what Mother Nature can do given enough time.

Re:Calculus? (4, Interesting)

arth1 (260657) | about 7 months ago | (#46542083)

Indeed. This is more like the smart bomb sights or artillery computers from WWII. Analogue all the way, and because of that, incredibly fast.

A dog catching a hubcap-like plastic object is a more complex operation, and the brain is involved, running an evolved trajectory program that isn't very fast, nor very accurate, and tends to freeze when run in parallel. But it's fast enough and accurate enough that the dog catches the thing most of the time.
Presumably, some far distant ancestor caught falling fruit or jumping fish, or catching tidbits flying from your parents ferocious eating, and the ability to just do slightly better than your peers meant greater chance of survival for you and your offspring.
These days, the genes might be favored again, because we like dogs to play with us.

Well, that's how it works outside Oklahoma and Alabama, anyhow.

Re:Calculus? (1)

tlhIngan (30335) | about 7 months ago | (#46543859)

A dog catching a hubcap-like plastic object is a more complex operation, and the brain is involved, running an evolved trajectory program that isn't very fast, nor very accurate, and tends to freeze when run in parallel. But it's fast enough and accurate enough that the dog catches the thing most of the time.

Don't forget the emphasis on feedback - visual and otherwise. The dog catching the Frisbee isn't strictly obeying classical physics, so you can't say they're doing physics. Instead, the dog is reacting to multiple stimuli - it sees the Frisbee, it estimates the distance to the Frisbee, and based on its previous experience, where it's headed and how long it has to get there.

It moves, then it quickly re-evaluates what happened - did a wind gust suddenly move it to a different location? If so, start heading in new direction.

For very short throws it will react purely based on reflex.

Teach a puppy sometime and you'll find early on it doesn't quite get the timing right, and once it does, you still can fake it with an empty throw. You know, where you go through the motions of throwing the ball, but not actually releasing it. The dog will start its run but after a few steps it will stop once it realizes the object is not where it's supposed to be as the feedback expected is not there.

I've found very few dogs that will run to the expected location without checking the object trajectory, signifying feedback is quite important in the process.

Re:Calculus? (1)

arth1 (260657) | about 7 months ago | (#46544827)

I've found very few dogs that will run to the expected location without checking the object trajectory, signifying feedback is quite important in the process.

No, but I had one that would look at the thrown ball, then start running under it without looking again, passing it, and turning around to catch it where she felt it should land. She seldom was off by more than a dog could twist, even for pretty long throws.

I'm not sure many humans could do the same, except baseball and cricket pros, but they don't run nearly as long distances and don't overtake the ball.
So in some respects, I think the dog's ability to estimate a thrown object's landing position is at least as good as ours.

Cats, on the other hand, seem to lack the knack except for direct line of sight. Which is why it's so fun watching them chase things and make a mess of it. Again and again.

Re:Calculus? (1)

drinkypoo (153816) | about 7 months ago | (#46542305)

It is both more and less amazing than that. It's still not doing calculus. It's just doing whatever feels right. What's amazing is that nature has produced such an efficient nerve cluster which can provide the appropriate reaction. What's hilarious is that because it fits a mathematical model, we think the insect is doing the math. No, it's just moving the only way it can move, and the results are best described by calculus, a math we devised to understand things we saw in nature.

Re:Calculus? (1)

MightyYar (622222) | about 7 months ago | (#46542509)

To be fair, each neuron is probably doing some mathematical function (in the form of a series of chemical reactions) and then passing the results to the next neuron. The end result is the same as an analog computer performing some hard-wired calculus function. In the end we are arguing semantics, not what is happening in actual fact. I'm much less interested in how each Slashdotter defines "calculus" and much more interested in how fruit flies do so much with so few neurons.

Semantics is exactly the bloody point (0)

Anonymous Coward | about 7 months ago | (#46543645)

To be fair, each neuron is probably doing some mathematical function (in the form of a series of chemical reactions) and then passing the results to the next neuron. The end result is the same as an analog computer performing some hard-wired calculus function.

Calculus - in fact all math - is a descriptive symbolic system that humans use in order to transfer knowledge about phenomena. The chemical reactions are not using the representation and communication system we call calculus at any point, it's using a completely different language that's domain-specific to the function of the fly's wing apparatus, composed primarily of electrical and chemical systems bearing little resemblance to anything we think or write on paper.

To say they are the same is equivalent to saying the sun and the moon are the same thing because both of them shed light on earth. It's ignoring titanic divergence in favor of narrowly defined and superficial functional similarity.

In the end we are arguing semantics, not what is happening in actual fact.

Yes, No. We are arguing semantics and semantics are language features and math is a language so we are talking about what's happening in actual fact.

I'm much less interested in how each Slashdotter defines "calculus" and much more interested in how fruit flies do so much with so few neurons.

Oh, damn, sorry about the above rant then. Carry on, my bad.

Re:Semantics is exactly the bloody point (1)

MightyYar (622222) | about 7 months ago | (#46543793)

Yes, No. We are arguing semantics and semantics are language features and math is a language so we are talking about what's happening in actual fact.

Math is a language of precision. English is, for the most part, not. When we need precision, we have to use some subset like "legalese". Complaining about imprecise language in a scientific journal is one thing - complaining about the precision of a NY Times headline is quite another. Expecting the NY Times to write headlines that sound like scientific paper titles is not realistic IMHO.

FWIW, in the article they clarify with:
"Humans use calculus to solve these kinds of problem involving multiple changes in angular momentum, said Dr. Cohen. Exactly what math the neurons in the haltere system use is something for neuroscientists to investigate further."

Re:Calculus? (1)

AK Marc (707885) | about 7 months ago | (#46546653)

Feedback isn't calculus. The dog getting muscle memory for catches isn't doing calculus. So why would we assume the fly is "doing calculus"? Is it actually sensing force and calculating a response or just reacting with muscle memory? Yes, muscle memory and reactions are interesting phenomena, but it certainly isn't "flies doing calculus with their wings".

Re:Calculus? (1)

MightyYar (622222) | about 7 months ago | (#46546829)

A tuned feed-forward loop is pretty interesting, and it will be very enlightening to see how it is done by a natural neural network. If you did this with a man-built system, you would definitely use calculus to tune the system.

Re:Calculus? (1)

AK Marc (707885) | about 7 months ago | (#46546953)

No, you wouldn't necessarily. An algebraic approximation could be quicker to calculate and sufficiently accurate for the need. A feedback loop with an algebraic approximation could be faster to calculate and sufficiently precise. The trick with nature, is that it often evolves the most efficient way of doing an inefficient thing.

Re:Calculus? (1)

MightyYar (622222) | about 7 months ago | (#46547689)

You might very well end up implementing your routine with simpler math, but I'd bet a dollar that you'd first design the system in something like MATLAB before simplifying. And depending on the application, you might stop there because controller chips are so cheap now. PID with feedforward is possible on almost anything.

Re:Calculus? (1)

Dixie_Flatline (5077) | about 7 months ago | (#46543595)

Calculus is OUR way of DESCRIBING the motion or action that is happening. The fact that you can use calculus to determine the area under a curve doesn't mean that the area under a curve is 'calculus'. Or that the volume of an arbitrary vessel is 'calculus', just because you USE calculus to determine the volume.

The fly has evolved a set of behaviours that corrects for certain environmental conditions while it's flying. That's all. There's no real computation going on.

Re:Calculus? (1)

AK Marc (707885) | about 7 months ago | (#46546973)

Someone else pointed out the article says they doubt calculus is being done, but that if a human built an artificial bug to do it, we'd use calculus.

Tere's no evidence calculus is being done beyond an apple doing addition when it falls from a tree onto other apples. Just because addition happens, and that's how we'd describe it, doesn't mean that's what the apple is doing.

Re:Calculus? (2, Insightful)

Anonymous Coward | about 7 months ago | (#46541485)

That's like saying that a dog catching a ball or frisbee is doing calculus. Nope, it's experience.

It's not "experience" either. Basically, it's calculus. But the fly isn't doing the calculus. Evolution did the calculus using a massively parallel Monte-Carlo optimization akin to "stupidsort" (stupidsort randomly permutes a sequence and then checks whether it is sorted, iterating when it isn't).

Re:Calculus? (1)

goulo (715031) | about 7 months ago | (#46541889)

Indeed, it seems a rather strained idea of "doing calculus". It's seems like saying that when I pour one liquid into another, the liquids are "doing differential equations". Or when an apple falls, it is "doing algebra". And when the apple falls into a group of other apples, increasing their number, it is "doing addition".

Re:Calculus? (1)

Anubis IV (1279820) | about 7 months ago | (#46543325)

A better way of phrasing it would have been that it's engaging in an analog computation that provides an approximation of calculus. That is, using analog systems, it does the calculations necessary to come up with a result that is remarkably close to that which calculus would tell us is the correct answer, yet it does so without any of the higher-order reasoning and in a fraction of the time that it would take us to do so exactly.

As you said, dogs do the same thing when they run to catch a disc, just as we do when we throw a ball that is intended for a moving target. These calculations aren't calculus, however, they're merely approximations of calculus that, as you said, come through experience. That's why we'll occasionally overthrow the ball or come up short when running to make a catch, despite our arms or legs doing exactly what our brains told them to do.

Re:Calculus? (1)

AK Marc (707885) | about 7 months ago | (#46546917)

As someone else put it, that's like saying an apple falling off a tree is "doing addition". The apple doesn't do it. It's doing something we have given a name to, but isn't doing the thing described by that name.

Re:Calculus? (1)

Anubis IV (1279820) | about 7 months ago | (#46547299)

I believe I did a poor job explaining myself, since it seems you misunderstood what I wrote. I'm in full agreement with you, and was merely trying to provide an alternative and more accurate way of describing what was happening, yet your reply suggests that you were trying to contradict a point I didn't make.

As you said, an apple falling from a tree might be capable of having its descent described in terms of math, but that in no way suggests that the apple itself (nor the tree it fell from, obviously) is engaged in math (unless you subscribe to the "the whole universe is a giant computer" idea, but that's a topic for another day). Similarly, the fly, your dog, or a person catching a ball may be able to have their actions described in terms of calculus, but that in no ways suggests that they are actually engaged in calculus. Unless a person is calculating derivatives while the ball is mid-flight, saying that they are "doing calculus" would be a misstatement. In that, and in everything else you have said here, we are very much in agreement.

That said, I was attempting to introduce the notion that while a fly, dog, or person may not be engaged in calculus, they are engaged in some primitive computation, else they wouldn't be able to move to the right place or respond to a change in their environment, and that those computations can accurately be described as approximating the results that calculus would provide. Again, this does not mean that they are "doing calculus", and to say that they are would indeed be a misstatement, as you and I both agree. But it does mean that they are doing some form of organic computation which produces approximations of calculus.

Is it calculus? No. The results are similar, but the methods are vastly different. Is it as widely applicable as calculus? No. The methods used to know where to stand to catch a ball are domain specific, so while they may produce results that approximate calculus' in this domain, they wouldn't work in most others. Is it correct to say that they are doing calculus? Absolutely not.

Was I a bit clearer? If so, do you disagree with any of that? Again, I don't disagree with anything you've said, nor was I attempting to contradict any of it. I was merely attempting to add to it.

Re:Calculus? (1)

AK Marc (707885) | about 7 months ago | (#46547827)

your reply suggests that you were trying to contradict a point I didn't make.

Right back at you.

while a fly, dog, or person may not be engaged in calculus, they are engaged in some primitive computation, else they wouldn't be able to move to the right place or respond to a change in their environment,

I said nothing to contradict that. Humans have a well-studied "muscle memory", and this sounds a lot more like that than any conscious computation.

Again, this does not mean that they are "doing calculus", and to say that they are would indeed be a misstatement, as you and I both agree

Yup. I think they intentionally used inflamatory language to make it sound more interesting. My point is that they were "lying".

It's likely a feedback loop. There are many that have been examined and proven in nature (dogs catching things, for example). This doesn't look like anything new, just (maybe) faster or more accurate than seen before.

Is it calculus? No. The results are similar, but the methods are vastly different. Is it as widely applicable as calculus? No.

I don't think you'll get a clear definition of "calculus" here, either. if you use algebraic approximations for the area under the curve, is that "calculus"? Or do you have to take the limit as the block size approaches zero? Or an you just take the numerical transformation of the curve equation changing it to an area equation(x^2 ->2x)? After all, most of the common ones had geometrical proofs before calculus was "invented".

Re:Calculus? (1)

Anubis IV (1279820) | about 7 months ago | (#46549485)

Fair points, all around, and it looks like we're in vehement agreement with one another. ;)

Re:Calculus? (1)

AK Marc (707885) | about 7 months ago | (#46549579)

Yes, tone is lost in writing, and with near-anonymity, no real history would reveal the author's general tone.

Some kind of calculus? (1)

Anonymous Coward | about 7 months ago | (#46541167)

When I learn they can analytically solve arbitrary partial differential equations I'll take even more pleasure in swatting the little buggers.

Time, distance, motion, acceleration (3, Informative)

Todd Palin (1402501) | about 7 months ago | (#46541171)

Time, distance, motion, and acceleration are all things that a moving organism needs to master to survive. These things can be mathematically calculated using calculus, and calculus can certainly explain the interconnectedness of these things, but it is unreasonable to say that a fruit-fly uses calculus to fly. If fruit-flies use calculus then so do amoebas.

Re:Time, distance, motion, acceleration (1)

DoofusOfDeath (636671) | about 7 months ago | (#46541545)

Agreed. Calculus is a specific mathematical, symbolic approach to computation. Solving the same kinds of problems by a different means is not calculus.

Re:Time, distance, motion, acceleration (1)

Warbothong (905464) | about 7 months ago | (#46541847)

If fruit-flies use calculus then so do amoebas.

Rocks do calculus when they roll down hills, since they always make sure to only move a distance which exactly matches the integral over time of their velocity.

Circles do calculus too, since they always choose their area such that it corresponds to the integral over their radius of a circumference.

Re:Time, distance, motion, acceleration (4, Funny)

Anonymous Coward | about 7 months ago | (#46541951)

This is nothing. My desk lamp does REAL-TIME ray tracing!

Especially when I put a couple reflective spheres on a checkerboard underneath it.

Pffft NewBees (1)

Tablizer (95088) | about 7 months ago | (#46541297)

Call me back when they do my taxes

What a retarded headline (2, Insightful)

Anonymous Coward | about 7 months ago | (#46541317)

So when a dog catches a frisbee, is it doing calculus with its teeth?

Re:What a retarded headline (0)

Anonymous Coward | about 7 months ago | (#46542915)

Of course. Why do you think they eat all that homework? For the flavor?

Next they'll discover... (1)

John Allsup (987) | about 7 months ago | (#46541413)

that humans do signal processing with their brains, and that such processing involves complex analysis. One day they'll learn that those squiggly symbols in maths books actually mean something. It's an embarrassment to science that these insect chasers are called scientists rather than sciensecoolhuhwowists. End rant of an old school fundamentalist.

Which kind? (1)

VortexCortex (1117377) | about 7 months ago | (#46541745)

doing some kind of calculus in a little 'integrated circuit' of neurons

If it's using a dedicated integrated circuit the calculus they perform must be integral.

no more than (2)

Chrisq (894406) | about 7 months ago | (#46541747)

no more than a football player does calculus when changing course to intercept the ball.

Re:no more than (1)

jones_supa (887896) | about 7 months ago | (#46542225)

So I'm doing it wrong when running on the field with a notebook and calculator?

Re:no more than (2)

hawkinspeter (831501) | about 7 months ago | (#46542359)

Yes, you should be carrying a slide-rule.

Re:no more than (0)

Anonymous Coward | about 7 months ago | (#46543081)

I don't think it is fair for you to continue the stupid jock stereotype. Just because most football players rely on chance to hold a calculator the right way doesn't mean they can't do calculus. They are more likely to think like a PID control loop with feed forward response to incoming step increases like an opposing player impact.

they don't have to show their work on paper? (0)

Anonymous Coward | about 7 months ago | (#46541879)

that's how they can get away with all that sleek acrobatic stuff? unburdened by slow learning 'teachers' using fake figures? even monkeys have more fun than us, share their bananas, & still fail to shoot each other... something to be said for civilized turd flinging & remaining hymenless as far as for accounting purposes

Little known calculus wizardry of Babe Ruth (1)

140Mandak262Jamuna (970587) | about 7 months ago | (#46542035)

Babe Ruth said, "How can you think and hit at the same time?". But that was an intentional misdirection to throw his competitors and rivals off track. Slow motion analysis of ancient footage shows the slugger smuggled into the base a slide rule, a theodolite, an anemometer and a protractor all hidden in his jersey. You really don't believe some one could be that fat and be a star athlete didn't you? The truth is out, he was not fat, he was hiding these instruments in his jersey. He used them to calculate the trajectory of the pitch and the angle and speed at which he should hit the ball.

Well, enough posters have made the same point. But there is some interesting science hidden behind that stupid title and summary. Why does the fly respond to changes in airflow but not the airflow itself?. Flies have very low mass for the amount of surface area they expose to the air stream. Given all the little hairs and wing surface area, the air will feel to them as thick as oil feels to us. They will simply be carried by the air flow. It is not just that they can't fight it, they can't even feel it. It is like us sitting on the surface of the Earth which has a linear velocity of 1500 miles per hour at the equator, but we don't feel it. They can respond only to changes in airflow, which is turbulence. Quite interesting. Looks obvious once the result is known, but I would not have understood this purely based on theory. Of course there are fluid dynamicists who would have known this even before the experiment. Dale Anderson, Pletcher, Tannehill, Parpia .. may be they would have.

Everything is math. (0)

Anonymous Coward | about 7 months ago | (#46542517)

Everything is Math. Math is everything. Further reason to believe we are in a simulation.

Boring: A neural net can approximate diff-eq (1)

Theovon (109752) | about 7 months ago | (#46542755)

The fly’s brain is not doing calculus (or rather, differential equations). It’s a neural net that has evolved to respond to stimulus in a way that appears like what we’d use diff-eq for. Within certain bounds of range and accuracy, we can make artificial neural nets do this. So why is it surprising that meatware that evolved over millions of years can do the same thing?

Re:Boring: A neural net can approximate diff-eq (1)

Anonymous Coward | about 7 months ago | (#46543133)

The story is not "the fly's brain does calculus". The story is "a region in the fly's nervous system outside the brain has an autonomic role in fast recovery from perturbations of the flight (statespace) trajectory".

You know that kneejerk reaction (the real one, not the figurative one)? That's the same deal - the signal doesn't get to the brain before the knee jerks, but the jerk is mediated by neuron groups in the spinal cord. So the spinal cord is not just a communication channel, it also embeds control systems all along its length. For the same reason, you can move your hand away from a burning-hot object before your brain even finds out that it's hot.

The main difference here seems to be that recovering from perturbations in a flight trajectory is a bit more impressive than jerking a knee or yanking a hand away. In other words, this is a fairly complex neural circuit found outside the brain.

Mind you it's not really news; Stafford Beer was writing about the existence and role of these systems in the 70s, and that was based on neuroscientific knowledge from the 60s. I'm not quite sure what the big surprise is, but I'm guessing it's the relative complexity i.e. it's not just a basic stimulus/response, it's actually "doing calculus" (i.e. not "doing calculus" at all, but solving a differential equation numerically using analog computation).

Re:Boring: A neural net can approximate diff-eq (1)

Theovon (109752) | about 7 months ago | (#46546703)

Someone should mod up the AC’s comment.

DARPA will use this info, wait and see (0)

Anonymous Coward | about 7 months ago | (#46542775)

All of you who think this study is a waste of resources simply don't understand
that your masters are making sure they remain your masters.

Drones which can fly like an insect are desirable because they
can be much more difficult to shoot down.

When the giant fly-like drone swoops in on you to deliver a killing sting,
then you will understand, though you will have fractions of a second to
do so before you die.

Nonsense (1)

argStyopa (232550) | about 7 months ago | (#46542811)

This is no more 'fly doing calculus' any more than people do calculus when they throw a snowball at a target.

Not to say that I'm not occasionally amazed at the staggering mathematical underpinnings of some of what we internalize as fairly simple things:
- seeing - and interpreting - an image with light and color.
- hitting a moving target with something
- the signal complexity involved in muscle coordination to do just about anything.

Hmm... (1)

lmcgeoch (1298209) | about 7 months ago | (#46542895)

Fruit flies that do calculus? Next time I see one I will give it a practice AP test. I wonder if it considered cheating if a fruit fly is in the room during a calculus exam.

RC (1)

fulldecent (598482) | about 7 months ago | (#46543043)

You what simple circuit implements calculus (i.e. can integrate and differentiate)?

An R-C circuit.

Move along, happy Friday.

KCDoodle (1)

kcdoodle (754976) | about 7 months ago | (#46545211)

Math is my favorite subject.

The nerve cells immediately after the rods and cones in your eyes (and most other animal kingdom eyes) also perform calculus. Edge detection is done BEFORE visual stimuli makes it to your brain. The image and the edges reach your CPU at the same time. This lets you know where things start and where they end. It is a great asset when hunting chasing and running away.

However, it can get confused. This is the reason zebras have stripes and run in herds. With a large number of edges, the predator can become confused of where one zebra ends and the next zebra begins.

I did not learn this stuff in Biology class, I learned it in Robot Vision class.

Showing my age here but (0)

Anonymous Coward | about 7 months ago | (#46545455)

Maybe we should rename the Fruit Fly to "Fruit Fly DX". ;)

What about ants? (1)

antdude (79039) | about 7 months ago | (#46545849)

I didn't do calculus well. :(

Gyroscope Organ - Amazing (1)

umarekawaru (1030730) | about 7 months ago | (#46548409)

It's fascinating to me that flying insects such as these have gyroscopes called halteres which directly feed information to it's autonomic flight correction system which is as well designed as our most responsive fighter planes, if not better.

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