Strong Signals

[Xerographica]

My stomach just growled. Yesterday I told my friend Dave that I get the feeling that stomachs probably growl for some evolutionary reason. He disagreed.

When your stomach growls it proves that you're hungry. Would this proof have been advantageous to our ancestors? Yes, if proof was needed.

Imagine that we're both cavemen. You tell me that you're really hungry and ask for some of my food. Food is pretty scarce so I don't want to give you any if you aren't truly hungry. How can I be certain that you aren't lying? Well, if your stomach growls then this proves that you aren't lying. It proves that my food will be put to good use.

Your growling stomach is a trustworthy signal. It's a signal that can't be faked. Your growling stomach always honestly communicates your need for food.

In our modern times it can be embarrassing when other people hear your stomach growl. It's awkward for your stomach to inform a random person in the elevator that you are really hungry. Perhaps he offers you a snickers bar. It's not like you can pretend that you're not hungry.

What do you think? A quick Google search provides this article... Why does your stomach growl when you are hungry? It provides a physiological explanation but no evolutionary one.

[Bombadil]

Though the rate and force of peristalsis typically increases in the presence of food, activity also increases after the stomach and small intestines have been empty for approximately two hours.

Doesn't seem to prove you're hungry according to your article, it might be louder.. but it doesn't only happen when hungry. The growl might just be sound side effect of the evolutionary advantage of pushing substance through your stomach and intestinal system.

[Imperium Sidhicum]

It's just gas moving through the bowels. I think it has nothing to do with evolution, there being more obvious and unmistakable ways of indicating hunger.

[New Greater Netherlands]

NSG is not your blog

[Pope Joan]

It's just gas moving through the bowels. I think it has nothing to do with evolution, there being more obvious and unmistakable ways of indicating hunger.

Right, it reminds me of the way the pipes in my housed rattle and knock at times, something to do with "water hammer".

Our house has not evolved its plumbing

[The Grim Reaper]

Why does your stomach growl when you are hungry? It provides a physiological explanation but no evolutionary one.

BECAUSE THERE ISN'T ONE (e: re communication - the article does actually detail the necessity of the processes that produce a growl as being the contractions that help clear the digestive system of leftovers).

We have not evolved growling stomachs as a communication device - I can't fucking hear other people's stomachs growling because not all of us were raised in a goddamn sitcom where people's stomachs conveniently growl during lulls in conversation and the laughtrack.

Your ENTIRE OP contradicts the first sentence of your only source.

Though stomach growling is commonly heard and associated with hunger and an absence of food in the stomach, it can occur at any time, on an empty or full stomach.

It's not an honest signal of anything short of the fact that your stomach is growling.

[Xerographica]

Are the physiological explanation and the evolutionary explanation mutually exclusive? When babies are hungry they cry. Their crying obviously has a physiological explanation... but you'd figure it would also have a pretty obvious evolutionary explanation as well. My guess is that most biological things have an evolutionary explanation. Otherwise it would imply that most of nature is random.

[Bombadil]

Otherwise it would imply that most of nature is random.

Do you think gene mutation has a purpose in and of itself.. truth is the result of that mutation is either damaging, of no consequence or an advantage to the organism.. the mutation can fit a purpose but not have inherent purpose, it's a random mutation.

Evolution is random, at best one could say that life increases in complexity but that is a statistical issue not a purpose of evolution.

You're straying into the Puddle Theory of things

[Xerographica]

Otherwise it would imply that most of nature is random.

Do you think gene mutation has a purpose in and of itself.. truth is the result of that mutation is either damaging, of no consequence or an advantage to the organism.. the mutation can fit a purpose but not have inherent purpose, it's a random mutation.

Evolution is random, at best one could say that life increases in complexity but that is a statistical issue not a purpose of evolution.

You're straying into the Puddle Theory of things

Mutations are random but evolution sure isn't. All organisms are subject to selection by nature...

It may be said that natural selection is daily and hourly scrutinising, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, whenever and wherever opportunity offers, at the improvement of each organic being in relation to its organic and inorganic conditions of life. - Charles Darwin, On the Origin of Species

It is scarcely possible to avoid comparing the eye to a telescope. We know that this instrument has been perfected by the long-continued efforts of the highest human intellects; and we naturally infer that the eye has been formed by a somewhat analogous process. But may not this inference be presumptuous? Have we any right to assume that the Creator works by intellectual powers like those of man? If we must compare the eye to an optical instrument, we ought in imagination to take a thick layer of transparent tissue, with a nerve sensitive to light beneath, and then suppose every part of this layer to be continually changing slowly in density, so as to separate into layers of different densities and thicknesses, placed at different distances from each other, and with the surfaces of each layer slowly changing in form. Further we must suppose that there is a power always intently watching each slight accidental alteration in the transparent layers; and carefully selecting each alteration which, under varied circumstances, may in any way, or in any degree, tend to produce a distincter image. We must suppose each new state of the instrument to be multiplied by the million; and each to be preserved till a better be produced, and then the old ones to be destroyed. In living bodies, variation will cause the slight alterations, generation will multiply them almost infinitely, and natural selection will pick out with unerring skill each improvement. Let this process go on for millions on millions of years; and during each year on millions of individuals of many kinds; and may we not believe that a living optical instrument might thus be formed as superior to one of glass, as the works of the Creator are to those of man? - Charles Darwin, The Origin of Species

[Purpelia]

In general I agree with you. That's what I think. That and that I am happy someone else on this forum has picked up the torch of realizing our bodies are machines crafted by evolution and not some sort of magical god given thing that does things because it can. Everything inside us, every mechanism and behavior no matter how complex or voluntary/involuntary/automatic can be explained through evolutionary sources.

As to why things are as odd as they are, I'll have you all keep in mind that evolution is a process not toward the best but toward the cheapest that works. And cost here is measured primarily by how much energy the system uses. Evolution it self is basically a process that goes something like this: Make bunch of random variants -> throw away the worst mistakes -> return to square 1. Not very sophisticated engineering but it gets the job done.

[The Grim Reaper]

In general I agree with you. That's what I think. That and that I am happy someone else on this forum has picked up the torch of realizing our bodies are machines crafted by evolution and not some sort of magical god given thing that does things because it can. Everything inside us, every mechanism and behavior no matter how complex or voluntary/involuntary/automatic can be explained through evolutionary sources.

As to why things are as odd as they are, I'll have you all keep in mind that evolution is a process not toward the best but toward the cheapest that works. And cost here is measured primarily by how much energy the system uses. Evolution it self is basically a process that goes something like this: Make bunch of random variants -> throw away the worst mistakes -> return to square 1. Not very sophisticated engineering but it gets the job done.

That is a wonderful general description of evolution that in no way validates Xero's claim that the human body has evolved a way to 'honestly signal' people about its hunger via a mechanism that is neither honest nor a meaningful signal.

As I edited into my post, well before Xero responded to it, my concern with his depiction of a grumbling stomach as an evolutionary feature is because he seems to be under the assumption that the /sound of grumbling itself/ can be understood as beneficial to fitness because it fits his pre-determined conception of economics and a human race that exists solely because of honest signals that must be accounted for in the modern world by increasingly more arcane and nonsensical economically rationalist postulates.

The growling of the stomach does not have an evolutionary benefit; there is no evidence that suggests such that has been presented so far. The only evidence presented by the OP is that the growling of the stomach, in fact, cannot be an evolutionary feature to signal hunger, because the source itself states that the physiological process that produces growling is not fundamentally associated with hunger. It cannot be an evolutionary honest signal, because it is not an honest signal. The evolution of the growling of the stomach is as a byproduct of the physiological processes required for the good health of the digestive system, and there is no evidence given to show that said evolution is communicative.

Pretty much everyone on this forum has an understanding of how evolution works, hopefully. A basic outline of evolution is not a moment of genius that substantiates a torch to be passed between NSG's joint prophets of biology against an imagined Young Earth Creationist homogeny that encapsulates the rest of NSG's community. The concern here is Xero's absolute zealotry about shoehorning evolution into his economic theory of everything.

Are the physiological explanation and the evolutionary explanation mutually exclusive? When babies are hungry they cry. Their crying obviously has a physiological explanation... but you'd figure it would also have a pretty obvious evolutionary explanation as well. My guess is that most biological things have an evolutionary explanation. Otherwise it would imply that most of nature is random.

Yes, they are mutually exclusive. The physiological explanation in your own OP, and the evolutionary explanation in your own OP, are mutually exclusive.

Proposition 1 (The physiological explanation): Though stomach growling is commonly heard and associated with hunger and an absence of food in the stomach, it can occur at any time, on an empty or full stomach. Though the rate and force of peristalsis typically increases in the presence of food, activity also increases after the stomach and small intestines have been empty for approximately two hours. (Quotes from your Scientific American article)

Proposition 2 (Your evolutionary explanation): Stomach growling is an honest signal of hunger.

Your understanding of evolution is an anti-scientific application of your economic ideals onto primitive societies, and furthermore is directly contradictory to the modern anthropological understanding of how the division of resources works in pre-market societies. Food was communally distributed, it wasn't just arbitrarily the responsibility of a guy who was eating a meal to share his meal with hungry people.

[Philjia]

Do you think gene mutation has a purpose in and of itself.. truth is the result of that mutation is either damaging, of no consequence or an advantage to the organism.. the mutation can fit a purpose but not have inherent purpose, it's a random mutation.

Evolution is random, at best one could say that life increases in complexity but that is a statistical issue not a purpose of evolution.

You're straying into the Puddle Theory of things

Mutations are random but evolution sure isn't. All organisms are subject to selection by nature...

It may be said that natural selection is daily and hourly scrutinising, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, whenever and wherever opportunity offers, at the improvement of each organic being in relation to its organic and inorganic conditions of life. - Charles Darwin, On the Origin of Species

It is scarcely possible to avoid comparing the eye to a telescope. We know that this instrument has been perfected by the long-continued efforts of the highest human intellects; and we naturally infer that the eye has been formed by a somewhat analogous process. But may not this inference be presumptuous? Have we any right to assume that the Creator works by intellectual powers like those of man? If we must compare the eye to an optical instrument, we ought in imagination to take a thick layer of transparent tissue, with a nerve sensitive to light beneath, and then suppose every part of this layer to be continually changing slowly in density, so as to separate into layers of different densities and thicknesses, placed at different distances from each other, and with the surfaces of each layer slowly changing in form. Further we must suppose that there is a power always intently watching each slight accidental alteration in the transparent layers; and carefully selecting each alteration which, under varied circumstances, may in any way, or in any degree, tend to produce a distincter image. We must suppose each new state of the instrument to be multiplied by the million; and each to be preserved till a better be produced, and then the old ones to be destroyed. In living bodies, variation will cause the slight alterations, generation will multiply them almost infinitely, and natural selection will pick out with unerring skill each improvement. Let this process go on for millions on millions of years; and during each year on millions of individuals of many kinds; and may we not believe that a living optical instrument might thus be formed as superior to one of glass, as the works of the Creator are to those of man? - Charles Darwin, The Origin of Species

Evolution is not simply about acquiring advantageous traits, it's about losing ones that confer a disadvantage. A lot of animals have evolved a digestive system that usually has a lot of gas in it, as a side effect of evolving a digestive system suitable for processing solids and liquids that we swallow. A digestive system filled with gas will be prone to making gurgling noises as the pressure equalises, particularly if there is much more gas than food. There is no particular disadvantage to having a digestive system filled with gas, so the population has retained this trait.

[Trumptonium]

Stomach growling, like sleepiness, is affected by your body clock.

Just like you're not able to sleep when you go too early or you feel tired if you wake up at different times every day even if you sleep the same hours, your stomach will growl when you eat at different times of the day or with different calorie compositions.

My stomach never used to growl regularly until I became 16, as I never ate lunches, but at 16 everyone at my school was allowed to leave for lunch. I used to go out and buy something almost every day for an entire school year. When I stopped or missed a day, my stomach would growl around lunchtime. Was like that for the entire summer until it was too embarrassing at college so I began going out again to eat at lunch or taking something with me. Stopped in my second year of college due to free periods around that time meaning no embarrassment, and the issue fixed itself after a few months.

[The Two Jerseys]

So what do my farts signal?

[Dumb Ideologies]

So what do my farts signal?

Breach of international chemical weapons treaties.

[Galloism]

Though the rate and force of peristalsis typically increases in the presence of food, activity also increases after the stomach and small intestines have been empty for approximately two hours.

Doesn't seem to prove you're hungry according to your article, it might be louder.. but it doesn't only happen when hungry. The growl might just be sound side effect of the evolutionary advantage of pushing substance through your stomach and intestinal system.

So what you're saying is we evolved in such a way that gives false signals if you merge the idea in the OP?

[New Gaireniahr]

honestly, i think that another signal for hunger would be unnecessary if people can already "feel" hungr

[Xerographica]

Your understanding of evolution is an anti-scientific application of your economic ideals onto primitive societies, and furthermore is directly contradictory to the modern anthropological understanding of how the division of resources works in pre-market societies. Food was communally distributed, it wasn't just arbitrarily the responsibility of a guy who was eating a meal to share his meal with hungry people.

The guy with food didn't randomly or equally share his food. Logically his distribution decisions were based on his available information. It seems reasonable that potential recipients had an obvious incentive to provide false information (exaggerate their need for food). Successful trickery helped the recipient and hurt the giver...

Deception in communication results in a fitness increase that is gained by the signaler and a fitness loss that is paid by the receiver (Mock 1999). - Mark E. Hauber and Caitlin K. Ramsey, Honesty in host-parasite communication signals

From that insight, Trivers reasoned that a physically weak offspring might use ‘psychological weaponry’ — specifically, begging signals that inflated its true needs. This would con parents into the desired (and, for the parents, deleterious) skew. It is not clear what might constrain such deceit, although various costs of the signals themselves have been proposed as forcing the whole system back to honest signalling. - Douglas W. Mock, Driving parents cuckoo

Regarding the handicap principle...

More generally, if there are mechanisms that allow honest communication without a handicap, these less expensive alternatives should be favored over handicap signals, which can impose an arbitrarily high cost on their creators. - W. Tecumseh Fitch and Marc D. Hauser, Unpacking "Honesty": Vertebrate Vocal Production and the Evolution of Acoustic Signals

[Greed and Death]

It's just gas moving through the bowels. I think it has nothing to do with evolution, there being more obvious and unmistakable ways of indicating hunger.

Right, it reminds me of the way the pipes in my housed rattle and knock at times, something to do with "water hammer".

Our house has not evolved its plumbing

find the offending pipes turn off their source of water then turn them on slowly.

[Xerographica]

So what do my farts signal?

According to a new video from the American Chemical Society (above), it’s all about one canine literally sniffing out important information about the other—its gender, emotional state, diet, and more. “Think of it kind of like speaking with chemicals,” the video’s narrator says, referring to the glandular secretions released by glands in a dog’s anal sac. “In fact, this butt-sniffing action is just one of many examples of chemical communication in the animal kingdom.” - David Freeman, Why Do Dogs Sniff Each Other’s Butts? It’s More Complicated Than You Might Imagine

“Man smells poorly,” Aristotle wrote, while Charles Darwin concluded that a sense of smell was of “extremely slight service” to the civilised human. When it comes to detecting odours, we have long dismissed human abilities as second-rate.

Now this view has been challenged in a scientific analysis that argues the human sense of smell has not only been underestimated, but that it may rival that of dogs and rodents. - Hannah Devlin, Not to be sniffed at: human sense of smell rivals that of dogs, says study

A particularly loud fart could say, "Pay attention! I'm about to send you some useful information!!!"

[Purpelia]

That is a wonderful general description of evolution that in no way validates Xero's claim that the human body has evolved a way to 'honestly signal' people about its hunger via a mechanism that is neither honest nor a meaningful signal.

You are correct. But I was not really trying to do that though. All I wanted to do is congratulate the man on picking up a worthy cause. One that most people don't.

Personally I feel that the mechanism has more to do with telling you that you are hungry than telling other people. Remember, humans are not supposed to be sedentary farmers that eat 3 square meals a day. That's something we've only been doing a really, really short period of time on evolutionary scales. Our biological ancestors were primarily hunter gatherers who would go around all day picking berries and stuff and eating as they went and supplement it through binging on meat products. And in that context telling someone he has not eaten in two whole hours is sort of like telling a modern person you've not eaten in days.

That's my take on it anyway. But it's not to say he is wrong. Or that I am right. The thing with these things is that whilst we know all our mechanisms are evolutionary in origin there is no way to exactly pinpoint the purpose or indeed if the mechanism in question is even there for a reason or if it is a side effect of some other mechanism that is with any degree of physical certainty. There is no evolutionary blueprint we can follow or look at.

The best we can do is pose reasonable conjecture based on the things that we do know and come to plausible explanations that match the facts. I feel that's why a lot of people reject the approach as well. They want all their explanations wrapped up in a little box with a bow on top that contains facts and figures, even if these are from a dusty makebelief tome.

[Xerographica]

Personally I feel that the mechanism has more to do with telling you that you are hungry than telling other people.

From my perspective, the concern is the efficient distribution of a scarce resource... food. If there are two groups, whichever group allocates food more efficiently will have a competitive advantage over the other group. The efficient allocation of food depends on accurate/reliable/trustworthy/credible information about each individual's need for food. The problem is that people have an obvious incentive to exaggerate their need for food. For me the obvious solution is trade. If you're willing to sacrifice something valuable for food, then this proves that you truly need it. Sacrifice is a costly signal, which makes it a reliable signal. The less obvious solution, which can only work in relatively small social networks, is the proof offered by a growling stomach. A growling stomach is not a costly signal. What makes it reliable is that it's hard to fake. So it's theoretically possible for growling stomachs to help improve the efficiency of food allocations.

I haven't managed to find any direct support for this theory. But there's plenty of indirect support... Honest begging: expanding from Signal of Need. It really can't be the case that honest signals of need are only relevant to birds. The efficient distribution of food is relevant to all animals. Therefore, honest signals of need are relevant to all animals.

[Major-Tom]

Sometimes if your stomach growls, it's the first sign that you had too much Chipotle for lunch and are gonna pay a heavy price.

[Holy Tedalonia]

My belly used to occasionally growl when I wasn't hungry. People usually interpreted it to do with hunger. Every time I roll my eyes.

[Galloism]

My belly used to occasionally growl when I wasn't hungry. People usually interpreted it to do with hunger. Every time I roll my eyes.

Why do you send false signals? No one would ever do that.