I trained myself to wiggle one ear as a kid and it's exactly like this. The muscle is much stronger in that ear and there's a weird reflex that when something startles me from behind, the same muscle that makes the ear wiggle triggers. It happens in the untrained ear as well.
When I was a lad, I spent some time in front of a mirror trying to teach myself to move my eyebrows independently, like Spock. I eventually succeeded, but in the process I also learned how to move my ears. One downside is that these ear muscles began to involuntarily try to help. For instance, if I am looking down while wearing glasses, my ears contract to grip the glasses so they don't fall off, and after a while these seldom used muscles ache from the effort.
It was only at the age of 50-something that I found out that my ability to move my eyebrows independently is not a general population thing. Amaze! Also FWIW I can wiggle both my ears, and independently too. Is there a way to make money from this ?
A quick googling reveals: "About a third of all people can raise one eyebrow: left or right. [..] But the ability to raise both eyebrows separately is much rarer. If you're not among them, that's because you cannot yet control and move the corresponding muscles."
I wouldn't say I trained it, but I learned to control it.
I do find myself pricking up my ears to hear better, not always consciously.
FWIW, I can raise my eyebrows individually, flare my nostrils, twitch my nose, and also flex some muscle which pops my ears. Useless human tricks. Except popping my ears; super useful on airplanes.
> and also flex some muscle which pops my ears. Useless human tricks.
Also useful when you're diving. I can equalise without holding my nose for the first 10-15m, just by doing the thing with the ears. Doesn't work all the way down tho...
The method involves closing the mouth and pinching the nose shut and trying to "exhale". As the wiki notes further down, this can cause damage to your hearing if you do it too forcefully, so use other methods first.
I don't know? I was really young, and as far as I can recall I just did it one day.
I always thought it was a muscle in my ears, but I remember looking it up, and it's actually farther back like behind your throat or something. I can't do just one ear at a time, it's all or nothing.
Someone linked this wiki page [1] in the thread. This might be it.
> The effectiveness of the "yawning" method can be improved with practice; some people can achieve release or opening by moving their jaw forward or forward and down, rather than straight down as in a classical yawn,[6] and some can do so without moving their jaw at all by activating the tensor tympani muscle, which is heard by the individual as a deep, rumbling sound.
> During swallowing or yawning, several muscles in the pharynx (throat) elevate the soft palate and open the throat. One of these muscles, the tensor veli palatini, also acts to open the Eustachian tube. This is why swallowing or yawning is successful in equalizing middle ear pressure.
Someone recently told me that its genetic. Not everyone can control that muscle. I can, I learned it after seeing someone do it by lifting eye brows. I can control it without moving eyebrows now.
You trained it? I can wiggle each ear very visibly (and both). I hardly ever do but as I remember most people can’t. So i always assumed it was a DNA thing.
Not the person you're replying to, but is also trained myself to do it. I basically touched the area where the muscle is, tried to activate it ... time passes ... and some unconscious process figured it out. Now, as a responsible parent, I use my super power to troll my kids.
>> I can wiggle each ear very visibly (and both). I hardly ever do but as I remember most people can’t. So i always assumed it was a DNA thing.
After reading the article I think its a "use it or lose it" thing where the muscles and ability to control them atrophy in our modern environment. We have more competing sounds and external means to "turn up the volume" so we can hear a particular thing.
I can’t move my ears at all. My wife can do the following: raise either eyebrow; move either ear back and forth; move either ear up and down; twitch the upper left lip, or the upper right lip, or the lower left lip, …; and twitch either nostril.
There’s muscles in my ears that I have conscious control of that don’t really seem to do anything other than make a rumbling sound. They were fun to use when I was young playing, since I could make explosion sounds and get a realistic rumbling bass too. Are these the same muscles?
I can do this too. The article mentions it being “rare”, but it sounds like it hasn’t really been studied so might actually be common. From casual discussion with friends in the past I suspect it’s more like 30-50% of people.
Oh, so that's what that is? Crazy. Subjectively (besides the sound) it just felt like a vague pressure in my head, near the neck, so I never could figure out what the hell it was I was doing.
I do this sometimes when my ears are congested and I’m trying not to do weird things with my jaw where people can see, to open up my Eustachian tubes. It works about a third of the time.
There's money here to whoever can capture the activation of these muscles to control prosthetic cat ears. At the rate I see them the prosthetic cat ear market must be double-digit billions.
Seriously, though, it makes me wonder if the activation of these muscles could be used in a hearing aid application. Why not add a couple rear-facing highly directional mics and use these muscles to control their gain?
I have this weird muscle in my ears I can flex to block out (or at least lessen) loud noises. I've never been able to explain it adequately to anyone, or find out what is going on, but it's absolutely real and not just, wait for it, .. in my head :-)
In modern cars when the vehicle detects an impending collision it floods the cabin with pink noise to trigger a reflexive contraction of this muscle to protect the passenger's hearing from the even louder sounds of the collision and the airbags.
I can do the rumbling too. And a clicking too. I can even make someone else hear my ear clicking by having them press their ear to mine. I wonder if that's causes by the same thing.
Same here, I hear a rumbling. I do occasionally use this to block or lower very loud (potentially hearing-damaging) sounds if there are no other means available.
There's a lot of stuff that does something after we thought it didn't. I don't quite trust folk when they say "Oh, that's just there in your body but it doesn't do anything."
I get that some stuff genuinely doesn't because evolution deprecated it, but others we might not yet understand well enough to know this for sure.
My favorite – this is to some degree my interpretation though! – my favorite is the default mode network, a kind of constellation of brain activity.
It’s called the default mode network because they found it through magnetic resonance imaging or something like this, and this activity pattern was the first pattern they saw!… A-ha! This is the default mode network! The default! The default mode! Yes!… the activity pattern in the brain of a human who has been persuaded to go into a very tight-fitting tube and is there all alone and it’s not pleasant.
The default mode is activated during introspection and social isolation and among the things it does is generate the sensation of being something which is distinctly not part of the rest of the world.
I'm not one to typically have strong fear/anxiety responses in situations that aren't actually dangerous. However, I felt extremely uncomfortable being partially inserted into an MRI tube for a lower body scan. I couldn't imagine being shoved head first into that thing without being heavily sedated or completely knocked out.
The thought crossed my mind, to be sure! I talked about all that with the techs beforehand. "Are you sure this isn't going to yank my teeth out?" "Pretty sure. Now stop moving around."
I have a simple hiatal hernia. One of the treatment options is to basically put a weighted band around your esophagus above the stomach so that the weight holds everything downward so your stomach doesn't get pulled up through the hernia. I imagined being in a car accident or some other situation where I'm nonresponsive, the doctor ordering an MRI, and me re-enacting the scene from Alien. Nah, I'll take my chances with the hernia, thanks.
During my MSc I spent a total of more than 25 hours being scanned in an MRI machine for a study investigating the neurobiology of reading, and by the end of the study I was so relaxed in there that my main problem was not falling asleep because I was lying down with repetitive noises around me!
I don't really mind medical procedures like that. The time I got punched at Elephant Butte Lake and got stitches at the emergency room I went into a deeply relaxed state that scared the nurse because she thought I'd fallen asleep. Even the noise of an MRI machine is not that startling if you know it is coming.
Indeed. I have a brain tumor (not cancerous and controlled by medication) and for a few years after diagnosis I had to get MRI's every few months for the first year, then one every year for a few years. It was a bit nerve wracking the first couple times but now I can fall asleep in those machines lol.
I wouldn't worry much as an X-ray recipient. There was talk in the 1950s about the trade off of getting a routine chest X-ray, say to check if you have pneumonia if you see your doc about a respiratory infection, vs a hypothetical risk of cancer.
so I wouldn't be afraid to get one. The radiology technician though needs to take special precautions because they are around it all day. Personally I would avoid a CAT scan if it were feasible
Nah, energy is way too low. If they emitted enough for you to feel it you'd be dead in a week.
I certainly felt my last MRI though. New machine, so probably high powered. Abdominal/liver MRI. Every time the RF was on I could feel a gentle warmth throughout my midsection. Weird but cool.
The mandatory shielding around these rooms is robust. I shadowed a technician inspecting a newly fitted x-ray room and observed the very sensitive equipment used to verify absence of leakage. There was a small puncture in the lead shielding that was quickly found and resulted in a delay until patched.
I don't know what you mean by "around" but if you mean walking down the hallway outside the x-ray room, my guess it's the low frequency sound these machines often produce that you're reacting to and not x-rays themselves. Not to mention the almost sci-fi signage alerting your brain to danger.
And inside the shielding envelope, modern x-ray equipment is still at very low levels unless you're the patient (and even as the patient, imaging requires much lower levels than in the past).
Humans cannot feel x-rays in the dosages you'd experience in an x-ray room. A sufficiently powerful x-ray would feel hot the same way a bright light does.
Could be a million things you subconsciously notice.
* the warning signage
* things that are related to the lead shielding (micro changes in gravity, smell of lead salts, ...)
* infrasound caused by the machinery
* people waiting for an x-ray around who are less-than-happy...
The problem with this kind of thing is that it is often highly individual, and barely, if all measurable with our current scientific instruments. Some people keep claiming that humans are incapable of even hearing infrasound, or sense gravity, claiming anyone who can sense them is spreading new-age esoteric nonsense or is mentally ill. See also: Electrosensitivity.
I'm not saying these things do or do not exist, just that it is in the realm of possibility.
it’s not the first nor the last time wish that communities would not refrain from changing terminology. fitness is as important as accuracy and we shouldn’t be wary of dropping such inaccuracies, especially when they bring such strong connotations.
they dropped the "nuclear" bit because it is scary, it doesn't involve any ionizing radiation. It is all about making the nucleus wobble but not about splitting atoms. I have fond memories of doing NMR experiments in senior labs as a physics major.
On the theme: The phrase "junk" DNA always irritated me. I'm glad it is being replaced with "non-coding".
Anybody who has looked at a 4kb demo can intuit that "junk" code likely has a function, even if it isn't immediately obvious machine code for the host CPU. I'm no geneticist, and I understand cells aren't CPUs, but I've read enough to know there's at least a tenuous analogy to non-coding DNA and the kind of "junk" you might find reversing a 4kb demo that procedurally generates its output.
Yup, DNA turned out to not merely be a sequence of triplets telling a dumb matter printer which hard-coded proteins to make - at least according to what little I understand of evolutionary developmental biology[0], DNA is much more like procedural generation in gamedev or demoscene. That is, there's plenty of recipes for various structures and body parts, and then there's lots of DNA that's responsible for conditionally enabling or disabling or modulating those recipes, depending on more DNA that controls when and where and how much to enable them, and then more - a complex network of logic.
--
[0] - Didn't get much further than this four-minute intro to the field, but it is a good intro: https://youtu.be/ydqReeTV_vk.
(EDIT: It's actually the second part of a trio, that starts with a four-minute bottom-up overview of organic chemistry[1], and ends on a three-minute intro to nanotechnology[2]. I recommend the series together for how well it frames humans in relation to other life and universe as a whole.)
There’s also epigenetics with mechanisms like histone modification and DNA methylation that can control expression without changing the DNA, but still being heritable.
Only the first one is DNA, and only a small portion of 'coding' DNA was initially regarded as important.
My question is how? Structural organization implies information. Who thought "Nah, evolution put that in for shits and giggles"? Was it just things we couldn't observe at all without modern scanning electron micrography?
More to the point, there is still chromosome structure when the cell is normal mode, expressing proteins instead of replicating itself. It's just it is spread apart, probably like a pop-up book where "pages" will snap open and become accessible for transcription as part of gene regulation and other times will be folded up so genes in that section aren't expressed.
Some of the reason it is tough to make GMO products that are really effective is that it's not enough to put a gene in and have it expressed a little, you want to have it expressed a lot. For instance the first version of Golden Rice produced Vitamin A but not enough to matter, it took several years to make one that expressed the genes strongly enough that it made significant amounts of Vitamin A.
> Was it just things we couldn't observe at all without modern scanning electron micrography?
Perhaps also that we couldn't imagine, much less accept, that a dumb semi-random process tweaking bits could, over time, organize those bits into higher level abstract structures. We still mostly talk about evolution mutating genes, where perhaps if you zoom out a little, it's actually working at a higher level of abstraction.
Incidentally, this is the same outlook as some people have today wrt. LLMs - they can't accept the idea that backprop running on a blob of weights representing a simple (if large) graph can start encoding increasingly high-level, abstract organizational structures.
Can't observe and woefully hard to understand. Remember in the 1950's the only genetic disease they could trace to a mutation was sickle cell and that was guesswork. They didn't have any of the cute editing techniques or amplification and sequencing tools. It's a miracle they figured out what they did.
so the thing that makes this complicated is that having non-coding DNA that does nothing for an individual can still be helpful for a population. they essentially serve the same purpose as commented out code that is really common when devs aren't using version control. the comments won't affect the program as it currently exists at all, but they make it so small changes to the code can more easily change the functionality.
Maybe not as much commented as unused. Turns out, there's plenty of that in DNA, and you can force turning it on. See e.g. the bit about snakes growing legs in the video I linked - they still carry the blueprint for legs in their genome, but have it suppressed.
>> I don't quite trust folk when they say "Oh, that's just there in your body but it doesn't do anything."
If you expand that to "You don't need that" it covers the appendix, spleen, tonsils, wisdom teeth (even incisors can be removed to make room) and probably some other things. I'm in favor of keeping all your parts unless absolutely necessary, as all of these things seem to have at least marginal purpose.
1. They used to yank everyone’s tonsils at any provocation. There was a swing back to trying never to take them. I wish my pediatrician would’ve had mine removed after my nth tonsillitis so I didn’t have to have them out in my 30s. That was fun.
2. Having had an emergency appendectomy, I’m sympathetic to the notion of proactively snipping them any time you happen to be in there anyway. Getting a hernia fixed? Oh hey, let’s grab the appy while we’re at it!
Except the appendix is an important organ. It has a high concentration of immune tissue and supports the immune system in the gut, and it's also a "safe house" for beneficial bacteria in the case of food poisoning or other gut "clearing" events.
It absolutely should not be just nipped out proactively.
Those are all true. However, appendicitis is still the most common abdominal surgery worldwide[0] and lots of people still die of it. It's easy to make the case that someone already undergoing abdominal surgery where the surgeon has ready access to it could have long-term lower health risk by removing it.
If you live in a country with excellent healthcare and you're never far from a hospital, the calculus is a bit different. You'll probably be fine. If you regularly find yourself far away from modern medical clinics, it's easier to defend the idea.
I had appendicitis as a kid. If you've never experienced it, trust me, you don't want it.
If you practice good food safety and hygiene (and live around people who do the same) then removing the appendix during unrelated surgeries or even preemptively before long stays at a place without emergency healthcare can be beneficial.
It's a bit of a Chesterton's Fence situation: the appendix is really useful, but for you and me the benefit was much larger 300 years ago than it is today. Today the benefit is small enough that you can remove it with only minor considerations (like being more cautious about your gut microbiome, and having a slightly worse immune system)
Makes me wonder what we'd uncover with systematic longitudinal studies (within the same culture, rather than comparing populations with distinct cultures and genetic bases) on effects of male genital mutilation.
I would expect at least some evolutionary pressure to get rid of unused things in your body. Let's just take the appendix as an example because it's probably the most common "you don't actually need this" thing that people know about.
Some appendixes burst. Sometimes this kills people. Sometimes this happens before that person has been able to reproduce. Wouldn't this cause selection for people who at the very least don't have bursting appendixes (appendices just sounds wrong to my inner narrator in this context), but also for people who have smaller ones. Over time this pressure would decrease but shouldn't it theoretically over many many generations result in smaller and smaller, eventually disappearing, appendixes?
Whether a thing can be selected-out depends on the shape of the fitness landscape in the environment.
For example, appendix-bursts are clearly rare enough and treatable-enough that they cannot be selected-out in modern humans. (But almost nothing can if almost everyone is able to reproduce, and any selection effects will be driven by the number of children which is largely cultural.)
If a thing hasn't been selected out, you can roughly conclude either that:
1. The selection pressure to do so isn't strong. Either few appendix bursts occur in an ancestral env, or they don't disrupt reproduction bc they happen later in life, or are treatable, or other causes of death kick in before the appendix matters.
2. Or, if the selection pressure is strong, there is "nowhere to go" in gene-space that improves this aspect of fitness, within the search-radius. (Which is really equivalent to 1: the selection pressure isn't strong enough to search widely enough)
3. Or there is a stronger selection pressure for it, even if you can't figure out what it is, like the "backup gut bacteria" thing for the appendix. (Which is actually equivalent to 1/2 also: the selection pressure isn't strong enough to find a way to separate the upside from the downside)
I would think so. Who says that's not happening now? It seems reasonable that evolutionary pressure can be strong enough to have a significant impact in 1-2 generations (for example due to the introduction of a new environmental threat) or weak enough to take thousands of generations.
We used to think tonsils are optional as well, and there seem to have been some studies that find a link between tonsillectomy & Crohn's, Hodgkin's or even breast cancer (from wikipedia).
There surely must be vestigial parts in our organisms, like the one in the article, but more often than not we have no fucking clue how they interconnect with the whole and what their function is.
Appendix is being appreciated these days as a reservoir of good gut bacteria. So there’s actually probably some pressure to keep it around. Appendicitis is a thing but of course not everyone suffers it. Maybe in the primitive world you were more likely to see your skull meet a rock before that happened in significant numbers of people in the population to the point it affected offspring counts.
Agreed. There is, or at least were, some parts of the body that were only recently discovered and not just known about and assumed to be inactive. It was only in 2015 that lymphatic vessels were discovered in the central nervous system:
Man, does THAT sum up the current political climate in America.
There exists in such a case a certain institution or law; let us say, for the sake of simplicity, a fence or gate erected across a road. The more modern type of reformer goes gaily up to it and says, "I don't see the use of this; let us clear it away." To which the more intelligent type of reformer will do well to answer: "If you don't see the use of it, I certainly won't let you clear it away. Go away and think. Then, when you can come back and tell me that you do see the use of it, I may allow you to destroy it."[97]
The Chesterton fence argument is that you need to understand why the fence is there. If you do understand it, and still remove it, it doesn't say that's bad.
A lot of this comes from the assumption that our organs each have a single purpose, so if the obvious purpose is not relevant in humans then the organ is useless. But most organs serve multiple purposes.
Evolution works on a different timescale than what science divulgation headlines, and selected lineages to care about how to cross deadly valleys even though they might have appeared rarely. There's little room for baggage.
There is no grand design in biology. If something ain’t broke, evolution ain’t going to fix it. Retina in mammals facing backwards that gives rise to blind spot is one example. The laryngeal nerve that goes all the way down aorta and back up the neck is another
Not exactly. Everything in our body needs energy to maintain itself. It has to provide some value for the energy it consumes, otherwise not having it becomes an evolutionary advantage meaning evolution will gravitate towards it.
What a_c is getting at is that evolution can become trapped in local optima. The backwards retina in mammals is suboptimal, but it's locally optimal - the path from where we are to a better design (like the one in squid) is too long for evolution to hill-climb up to.
He mentions that even if you're a giraffe, you have nerves just as long running to the end of your spine, and from your spint to the bottoms of your feet, so the extra length of nerve isn't really a problem.
There is a pathway for every possible configuration. It doesn’t dictate whether a configuration is optimal. Maybe the laryngeal nerve isn’t that bad. But that doesn’t guarantee all anatomy and physiology optimal
Also, if something truly serves no purpose, evolution will allow it to go away.
The classic example is the enzyme needed to make vitamin C. In our primate ancestors that lived on a diet rich in vitamin C, there was no penalty to losing this enzyme. Mutations that destroyed its function were not selected against. As a result, we now can't make vitamin C; the remnants of the gene for the enzyme have been so damaged that there's no path back to the working version.
Eh evolution will certainly try to fix things that ain't broke, indeed it will try to vary just about everything at some point or another. Bad cable management remains because no one survives the intermediate steps between functional configuration A and optimal configuration Z.
Tonsils are a good example of this. New studies are finding that they may be part of the immune system. Anecdotally, I had mine removed as a child due to frequent tonsilitis. As an adult, I suffer from a number of airborne allergies. Most likely a coincidence, but it does make me wonder!
My grandfather managed to persuade me when I was 4 that beer comes out of man's nipples. Unfortunately, at the time he was supposedly too old for it to happen. And my father was too young. So, I've never seen it in action
This is not news. People know this. I can move my ears voluntarily, and when I'm trying to listen, I can feel that happening. It's probably half conscious. There is an intuitive purpose behind these muscles, which is to do the best impression of pricking up your ears that some evolutionary predecessor was able to do better.
I think there's a big difference between "activating" a muscle and "getting utility" out of it. Sure, maybe it activates sometimes, but what does it do? Well... nothing. It's a vestigial structure.
I learnt how to wiggle my ears when I got startled by a book falling from a shelf and my ears instinctively "raised". Picture a dog going from "idling" to "alert", with the ears pointing up. It was like that, but for humans.
I then said "Ooooh, so that's how you do it".
There has never been a doubt in my mind that the muscle is connected to "alert, listen closely".
There's a lot of odd stuff we're gradually figuring. Also interesting, some of the hair cells in the ear act as amplifiers and you can hook them up to an electrical sound signal and have them dance around:
I suspect the standard explanation for that as given under the youtube video:
> Since the amplitude, and hence the mechanical energy, of airborne sounds is tiny, the cochlea mechanically amplifies the incoming vibrations.
is wrong as it doesn't really make sense from an engineering point of view - if you've already detected the sound to activate the hair cell then that job's done. My theory is they actively damp down the large vibrations so you can pick up the small ones. There's a 10^5 amplitude difference between large and small.
> the cochlea mechanically amplifies the incoming vibrations
Is that even possible in principle? Amplifying requires adding energy, it has to be either provided from somewhere else or redistributed from other parts of the input.
EDIT:
Aha, but apparently this system is not a passive amplifier at all! Per Wikipedia[0], this is an active, electromechanical amplifier, which makes the explanation you quoted more reasonable (if not accurate).
My ears tire when hearing foreign languages spoken, it feels like my ears keep automatically trying to discern each word as if I might understand them.
I know how to look hard by squinting my eyes and trying to focus, talk hard by speaking as loudly as I can or smell hard by breathing in as much as I can, but how do you listen hard?
I've gotten at least two people (youths) to be able to raise a single eyebrow by placing their finger on their eyebrows and feeling their muscles activate as they raise and lower both eyebrows. Keeping your fingers on the eyebrow muscles, it's almost like your brain can start to "see" the two distinct muscles. It didn't take them too long (days not weeks, not hours) to be able to raise an eyebrow.
There's probably a biological component to it to, I'm not saying this will work for everyone because it didn't work for my spouse.
Science around human body movements is in its infancy. Motion capture can't differentiable various muscle group activations, resulting in the same motion pattern.
Electric activity sensors are not sensitive enough to capture individual muscle movements.
And there are not enough interesting subjects (top athletes, performers etc) available to scientists to improve models and methods.
It's funny because these developments come at a time where a large proportion of the world no longer really uses their body for their living.
I wonder how different our ancestors perceived the world when their survival depended on their athleticism and keen senses. What knowledge and skills were common that have been lost to us now? There have been articles on HN about scientists "discovering" humans can exert control over their pupils and more and more scientists are "accepting" that echolocation in humans is real and learnable.
There are some fascinating stories about kids abducted and raised by wolves - who, when they were eventually found and brought back into human society, showed seemingly "superhuman" senses of hearing and smell. The senses became more normal the longer they spent time in human society however.
Not sure how credible those stories are, but if they are, this would indicate that human senses are a lot more flexible than we believe they are.
Evolutionary pressure is pretty brutal to things that actually aren't used - building a muscle takes energy and is one more thing for the body to maintain. I don't see how it is fair to say "thought humans didn’t use". It is always "if it has a use, we aren't sure what it is yet". Nature isn't a perfect architect but the odds are just much better that the use is still to be discovered than that truly useless bits of the body exist.
What, if you learn about something at school it is automatically true? The same criticism applies there too. They were calling things like the appendix vestigial when it obviously isn't. People made a big deal about how it doesn't do anything and then it turns out it does something. Who'd have guessed. The so-called vestigial organs probably all have uses. I'd have a much easier time believing most of them do than none of them. Otherwise evolution would have done a much better job of weeding them out.
> The so-called vestigial organs probably all have uses.
You’re right that some organs have been labeled vestigial and turned out not to be, but there are other organs that we know are vestigial because they don’t occur in all humans (same goes for other species). Evolution doesn’t weed things out without there being relatively strong effects on survival, and some of these things don’t affect survival so they drift.
This also isn’t binary. There are organs that are still classified as vestigial, but have minor or secondary uses, perhaps enough for evolution to keep them around, or again perhaps because having them doesn’t result in any statistical mortality.
Speculating and/or carrying beliefs that contradict modern evolutionary biologists probably isn’t going to work out. School might not be always right, but it is most of the time, and it’s right more often than no school, right? https://en.wikipedia.org/wiki/Human_vestigiality
When I read "humans didn't use", I understand that other animals with which we share close common ancestors still use it. Evolutionary pressure can make organs go into disuse so it makes sense that we end up with unused organs.
A 1% reduction in body mass is a huge advantage evolutionary, especially since rather than being cut completely that mass could be repurposed as more muscle for competing or more fat for lean times. For something in very recent evolutionary history (talking the last few thousand years), yeah sure the pressure might not have optimised a wasted organ out. But for any random organ? Nah, they probably have a purpose and we don't know what it is yet. Otherwise there is a big advantage to removing 'useless' bits. Evolutionary processes do however love little random tweaks and whatnot because they serve a useful purpose in weird edge cases and it is much more likely we're looking at one of them in any particular case.
And the ability to breath fire would also be a huge advantage, but evolution does not seek advantages, it merely keeps mutations that happen to be beneficial. No one has been born with a mutation that has allowed them to breath fire (or if they were they obviously didn't have much reproductive success) and thus we are still unable to breath fire. No one who has been born with a mutation that prevents the development of ear muscles has had especially great reproductive success either.
> A 1% reduction in body mass is a huge advantage evolutionary
That thought fails to explain the wide natural variation in body mass of humans, and within each species on this planet.
Edit: for most species being smaller is a disadvantage. Mates statistically select for larger stronger individuals, and larger stronger individuals are statistically better at killing and defending.
A little study of biology will clear that up. Species inhabit different niches. They have different survival strategies. Each case requires a different optimal point.
Please elaborate, I think you misunderstood me. Are you defending the claim that 1% human body mass reduction is an evolutionary advantage? Your quip about biology should maybe be directed at @roenxi?
I was talking about variation within each species, not across different species. (Edited to clarify) I was talking, in context as a reply to the claim that losing a given vestigial organ would improve (lessen) mortality. Humans, for example, have wide natural variation in body mass, therefore the evidence contradicts the claim that “1% reduction in body mass is a huge advantage evolutionary”.
If a reduction in body mass was an evolutionary advantage, we’d be evolving to be smaller over time. That’s not happening. Why?
In fact, there is an evolutionary advantage in humans to being taller and having more muscle, since these traits are selected for by mates, and are beneficial for hunting.
The selective pressure of small unused organs may be very low and virtually disappear in the stochasticity of natural selection. It may take a long time for such elements to disappear completely
There is only evolutionary pressure on things that affect mortality. Vestigial organs can and do exist because there is no evolutionary pressure on them, because they don’t affect mortality.
I trained myself to wiggle one ear as a kid and it's exactly like this. The muscle is much stronger in that ear and there's a weird reflex that when something startles me from behind, the same muscle that makes the ear wiggle triggers. It happens in the untrained ear as well.
Weird phenomenon.
When I was a lad, I spent some time in front of a mirror trying to teach myself to move my eyebrows independently, like Spock. I eventually succeeded, but in the process I also learned how to move my ears. One downside is that these ear muscles began to involuntarily try to help. For instance, if I am looking down while wearing glasses, my ears contract to grip the glasses so they don't fall off, and after a while these seldom used muscles ache from the effort.
Keep at it, those ear muscles will be benching solid steel glasses in no time!
Remember; Pain is weakness leaving the body.
It was only at the age of 50-something that I found out that my ability to move my eyebrows independently is not a general population thing. Amaze! Also FWIW I can wiggle both my ears, and independently too. Is there a way to make money from this ?
There probably is a way to make money off this, but while doing so I’m thinking you also would be selling some dignity along with it.
Isn't that true of more work than any of us care to admit ?
Now more than ever.
Huh, how is it not a general population thing? To raise an eyebrow is a common expression
A quick googling reveals: "About a third of all people can raise one eyebrow: left or right. [..] But the ability to raise both eyebrows separately is much rarer. If you're not among them, that's because you cannot yet control and move the corresponding muscles."
I think he means alternating raised eyebrow. Raising my left eyebrow is easy but my right requires some significant contortion of my face to achieve.
Yup I have the same issue with the aching muscles.
I wouldn't say I trained it, but I learned to control it.
I do find myself pricking up my ears to hear better, not always consciously.
FWIW, I can raise my eyebrows individually, flare my nostrils, twitch my nose, and also flex some muscle which pops my ears. Useless human tricks. Except popping my ears; super useful on airplanes.
> and also flex some muscle which pops my ears. Useless human tricks.
Also useful when you're diving. I can equalise without holding my nose for the first 10-15m, just by doing the thing with the ears. Doesn't work all the way down tho...
If you can’t will your ears to pop, here’s the manual way: https://en.wikipedia.org/wiki/Valsalva_maneuver
The method involves closing the mouth and pinching the nose shut and trying to "exhale". As the wiki notes further down, this can cause damage to your hearing if you do it too forcefully, so use other methods first.
True, but it's really, really easy to not do it so hard that you blow your eardrums out. Scuba divers do this all the time.
That's a way, and perhaps the most common, but far from the best. In particular, it has to be used preemptively before pressure builds up.
https://en.wikipedia.org/wiki/Ear_clearing
I have a lot of trouble on airplanes. How did you learn to do that?
I don't know? I was really young, and as far as I can recall I just did it one day.
I always thought it was a muscle in my ears, but I remember looking it up, and it's actually farther back like behind your throat or something. I can't do just one ear at a time, it's all or nothing.
Someone linked this wiki page [1] in the thread. This might be it.
> The effectiveness of the "yawning" method can be improved with practice; some people can achieve release or opening by moving their jaw forward or forward and down, rather than straight down as in a classical yawn,[6] and some can do so without moving their jaw at all by activating the tensor tympani muscle, which is heard by the individual as a deep, rumbling sound.
> During swallowing or yawning, several muscles in the pharynx (throat) elevate the soft palate and open the throat. One of these muscles, the tensor veli palatini, also acts to open the Eustachian tube. This is why swallowing or yawning is successful in equalizing middle ear pressure.
[1] https://en.wikipedia.org/wiki/Valsalva_maneuver
There’s a couple actors that do this. Their character gets surprise or concerning news and their ears (and sometimes also their scalp) moves.
I find it very distracting personally.
I can wiggle either ear independently. It greatly annoys my wife and my kids :D
I've always been able to wiggle my ears, but just today I learned if I focus I can do one at a time. I'm 33. Thanks for the useless new skill!
Me too but it annoys no one I know. Best use case is when I need more bass in my IEM's.
>weird reflex that when something startles me from behind
If you have cats and make a noise behind the ears automatically swivel back. I guess we must have something live that in our evolutionary past.
Someone recently told me that its genetic. Not everyone can control that muscle. I can, I learned it after seeing someone do it by lifting eye brows. I can control it without moving eyebrows now.
You trained it? I can wiggle each ear very visibly (and both). I hardly ever do but as I remember most people can’t. So i always assumed it was a DNA thing.
Not the person you're replying to, but is also trained myself to do it. I basically touched the area where the muscle is, tried to activate it ... time passes ... and some unconscious process figured it out. Now, as a responsible parent, I use my super power to troll my kids.
I too trained it when I was in primary school after seeing a class mate do it.
And like OP I eventually managed to control one ear (right) but not the other, even to this day 40 years later
I can twitch my left ear independently from my right. But not the right one independently. I'm sure it means something. Both at the same time is easy.
Same here, same ear
>> I can wiggle each ear very visibly (and both). I hardly ever do but as I remember most people can’t. So i always assumed it was a DNA thing.
After reading the article I think its a "use it or lose it" thing where the muscles and ability to control them atrophy in our modern environment. We have more competing sounds and external means to "turn up the volume" so we can hear a particular thing.
It could be both
I can’t control wiggling my ears, but I also have felt my ears perk up when listening to strange sounds. Sometimes accompanied by goosebumps and ASMR.
I can also wiggle both ears and tend to do the same thing. Always just thought I was weird.
My ears won’t move but I can flip my tongue over. I assumed everyone could, but nope. Bodies are so wonderfully weird and adhoc.
useful for listening to someone through earbuds as well -- moving back the ear creates an air gap
I can’t move my ears at all. My wife can do the following: raise either eyebrow; move either ear back and forth; move either ear up and down; twitch the upper left lip, or the upper right lip, or the lower left lip, …; and twitch either nostril.
There’s muscles in my ears that I have conscious control of that don’t really seem to do anything other than make a rumbling sound. They were fun to use when I was young playing, since I could make explosion sounds and get a realistic rumbling bass too. Are these the same muscles?
Seems like not:
https://en.wikipedia.org/wiki/Tensor_tympani_muscle
I can do this too. The article mentions it being “rare”, but it sounds like it hasn’t really been studied so might actually be common. From casual discussion with friends in the past I suspect it’s more like 30-50% of people.
Same here and I always sort of assumed this was a normal thing of the human body. I'm kinda shocked to learn that many people can't do it.
What kind of muscle can switch between voluntary or involuntary depending on the person?
Oh, so that's what that is? Crazy. Subjectively (besides the sound) it just felt like a vague pressure in my head, near the neck, so I never could figure out what the hell it was I was doing.
https://www.reddit.com/r/earrumblersassemble/
I do this sometimes when my ears are congested and I’m trying not to do weird things with my jaw where people can see, to open up my Eustachian tubes. It works about a third of the time.
There's money here to whoever can capture the activation of these muscles to control prosthetic cat ears. At the rate I see them the prosthetic cat ear market must be double-digit billions.
Seriously, though, it makes me wonder if the activation of these muscles could be used in a hearing aid application. Why not add a couple rear-facing highly directional mics and use these muscles to control their gain?
I have this weird muscle in my ears I can flex to block out (or at least lessen) loud noises. I've never been able to explain it adequately to anyone, or find out what is going on, but it's absolutely real and not just, wait for it, .. in my head :-)
That's absolutely real. It sounds like you are describing the Tensor tympani muscle. https://en.wikipedia.org/wiki/Tensor_tympani_muscle
In modern cars when the vehicle detects an impending collision it floods the cabin with pink noise to trigger a reflexive contraction of this muscle to protect the passenger's hearing from the even louder sounds of the collision and the airbags.
https://spectrum.ieee.org/pink-noise-says-prepare-for-impact
I can do the same and also didn't know how to explain it until I stumbled upon this subreddit: https://www.reddit.com/r/earrumblersassemble/
So apparently we can control our tensor tympani muscle: https://en.wikipedia.org/wiki/Tensor_tympani_muscle
If I do that, I hear a rumbling. I never used it to block out sound.
According to the Wikipedia article it may be involuntary.
I can do the rumbling too. And a clicking too. I can even make someone else hear my ear clicking by having them press their ear to mine. I wonder if that's causes by the same thing.
> And a clicking too.
You should get a check-up, when I heard clicking I had some wax accumulation.
Same here, I hear a rumbling. I do occasionally use this to block or lower very loud (potentially hearing-damaging) sounds if there are no other means available.
Same. Wonder how common this is.
Sounds like you might have conscious control over your tensor tympani muscle[0].
[0]: https://en.wikipedia.org/wiki/Tensor_tympani_muscle
I tried explaining this to my wife and she thought I was crazy. Turns out she was right, but not for this reason.
Most people may not use these muscles, but I do, to adjust the focus of my bifocals as needed. Zoom and enhance!
That was how I learned to tense my ear muscles -- because I could see they made my glasses shift on my face.
There's a lot of stuff that does something after we thought it didn't. I don't quite trust folk when they say "Oh, that's just there in your body but it doesn't do anything."
I get that some stuff genuinely doesn't because evolution deprecated it, but others we might not yet understand well enough to know this for sure.
My favorite – this is to some degree my interpretation though! – my favorite is the default mode network, a kind of constellation of brain activity.
It’s called the default mode network because they found it through magnetic resonance imaging or something like this, and this activity pattern was the first pattern they saw!… A-ha! This is the default mode network! The default! The default mode! Yes!… the activity pattern in the brain of a human who has been persuaded to go into a very tight-fitting tube and is there all alone and it’s not pleasant.
The default mode is activated during introspection and social isolation and among the things it does is generate the sensation of being something which is distinctly not part of the rest of the world.
I'm not one to typically have strong fear/anxiety responses in situations that aren't actually dangerous. However, I felt extremely uncomfortable being partially inserted into an MRI tube for a lower body scan. I couldn't imagine being shoved head first into that thing without being heavily sedated or completely knocked out.
I had a head MRI and my main anxiety involved praying to any powers that be that my tooth crown was truly non magnetic.
Sweet Lord, that is a white hot fear. When you remember the really old metal filling you have right before the machine kicks on.
The thought crossed my mind, to be sure! I talked about all that with the techs beforehand. "Are you sure this isn't going to yank my teeth out?" "Pretty sure. Now stop moving around."
They put metal detectors even in schools these days, can't they put one before the MRI lab?
I have permanent braces attached to the back of my teeth. I know they're magnetic, i can feel a slight pull if i hold a magnet close to them.
I don't know what i'll do if i ever need an MRI, otherwise i'd probably just find it cozy..
I have a simple hiatal hernia. One of the treatment options is to basically put a weighted band around your esophagus above the stomach so that the weight holds everything downward so your stomach doesn't get pulled up through the hernia. I imagined being in a car accident or some other situation where I'm nonresponsive, the doctor ordering an MRI, and me re-enacting the scene from Alien. Nah, I'll take my chances with the hernia, thanks.
During my MSc I spent a total of more than 25 hours being scanned in an MRI machine for a study investigating the neurobiology of reading, and by the end of the study I was so relaxed in there that my main problem was not falling asleep because I was lying down with repetitive noises around me!
I don't really mind medical procedures like that. The time I got punched at Elephant Butte Lake and got stitches at the emergency room I went into a deeply relaxed state that scared the nurse because she thought I'd fallen asleep. Even the noise of an MRI machine is not that startling if you know it is coming.
Indeed. I have a brain tumor (not cancerous and controlled by medication) and for a few years after diagnosis I had to get MRI's every few months for the first year, then one every year for a few years. It was a bit nerve wracking the first couple times but now I can fall asleep in those machines lol.
I feel uncomfortable around x-ray rooms. Can humans feel radiation or I am making it up?
I wouldn't worry much as an X-ray recipient. There was talk in the 1950s about the trade off of getting a routine chest X-ray, say to check if you have pneumonia if you see your doc about a respiratory infection, vs a hypothetical risk of cancer.
Today X-ray dosages are way less because they use
https://en.wikipedia.org/wiki/Digital_radiography
so I wouldn't be afraid to get one. The radiology technician though needs to take special precautions because they are around it all day. Personally I would avoid a CAT scan if it were feasible
https://en.wikipedia.org/wiki/CT_scan#Adverse_effects
Nah, energy is way too low. If they emitted enough for you to feel it you'd be dead in a week.
I certainly felt my last MRI though. New machine, so probably high powered. Abdominal/liver MRI. Every time the RF was on I could feel a gentle warmth throughout my midsection. Weird but cool.
The mandatory shielding around these rooms is robust. I shadowed a technician inspecting a newly fitted x-ray room and observed the very sensitive equipment used to verify absence of leakage. There was a small puncture in the lead shielding that was quickly found and resulted in a delay until patched.
I don't know what you mean by "around" but if you mean walking down the hallway outside the x-ray room, my guess it's the low frequency sound these machines often produce that you're reacting to and not x-rays themselves. Not to mention the almost sci-fi signage alerting your brain to danger.
And inside the shielding envelope, modern x-ray equipment is still at very low levels unless you're the patient (and even as the patient, imaging requires much lower levels than in the past).
Humans cannot feel x-rays in the dosages you'd experience in an x-ray room. A sufficiently powerful x-ray would feel hot the same way a bright light does.
Could be a million things you subconsciously notice.
* the warning signage
* things that are related to the lead shielding (micro changes in gravity, smell of lead salts, ...)
* infrasound caused by the machinery
* people waiting for an x-ray around who are less-than-happy...
The problem with this kind of thing is that it is often highly individual, and barely, if all measurable with our current scientific instruments. Some people keep claiming that humans are incapable of even hearing infrasound, or sense gravity, claiming anyone who can sense them is spreading new-age esoteric nonsense or is mentally ill. See also: Electrosensitivity.
I'm not saying these things do or do not exist, just that it is in the realm of possibility.
Does it make break down oxygen into ozone ? If it does maybe some people smell it
So this activity pattern could actually be the claustrophobia mode network?
Or "questioning the life decisions that led to finding myself in this situation" mode network?
this is so interesting.
it’s not the first nor the last time wish that communities would not refrain from changing terminology. fitness is as important as accuracy and we shouldn’t be wary of dropping such inaccuracies, especially when they bring such strong connotations.
For one thing the technology in an MRI based on a phenomenon known as nuclear magnetic resonance
https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance
they dropped the "nuclear" bit because it is scary, it doesn't involve any ionizing radiation. It is all about making the nucleus wobble but not about splitting atoms. I have fond memories of doing NMR experiments in senior labs as a physics major.
On the theme: The phrase "junk" DNA always irritated me. I'm glad it is being replaced with "non-coding".
Anybody who has looked at a 4kb demo can intuit that "junk" code likely has a function, even if it isn't immediately obvious machine code for the host CPU. I'm no geneticist, and I understand cells aren't CPUs, but I've read enough to know there's at least a tenuous analogy to non-coding DNA and the kind of "junk" you might find reversing a 4kb demo that procedurally generates its output.
Yup, DNA turned out to not merely be a sequence of triplets telling a dumb matter printer which hard-coded proteins to make - at least according to what little I understand of evolutionary developmental biology[0], DNA is much more like procedural generation in gamedev or demoscene. That is, there's plenty of recipes for various structures and body parts, and then there's lots of DNA that's responsible for conditionally enabling or disabling or modulating those recipes, depending on more DNA that controls when and where and how much to enable them, and then more - a complex network of logic.
--
[0] - Didn't get much further than this four-minute intro to the field, but it is a good intro: https://youtu.be/ydqReeTV_vk.
(EDIT: It's actually the second part of a trio, that starts with a four-minute bottom-up overview of organic chemistry[1], and ends on a three-minute intro to nanotechnology[2]. I recommend the series together for how well it frames humans in relation to other life and universe as a whole.)
[1] - https://www.youtube.com/watch?v=f8FAJXPBdOg
[2] - https://www.youtube.com/watch?v=ObvxPSQNMGc
There’s also epigenetics with mechanisms like histone modification and DNA methylation that can control expression without changing the DNA, but still being heritable.
There are something like (in the reference diagram I'm looking at) eight levels of organization in the structure 'chromosome': https://en.wikipedia.org/wiki/Chromatin#/media/File:Chromati...
Only the first one is DNA, and only a small portion of 'coding' DNA was initially regarded as important.
My question is how? Structural organization implies information. Who thought "Nah, evolution put that in for shits and giggles"? Was it just things we couldn't observe at all without modern scanning electron micrography?
More to the point, there is still chromosome structure when the cell is normal mode, expressing proteins instead of replicating itself. It's just it is spread apart, probably like a pop-up book where "pages" will snap open and become accessible for transcription as part of gene regulation and other times will be folded up so genes in that section aren't expressed.
Some of the reason it is tough to make GMO products that are really effective is that it's not enough to put a gene in and have it expressed a little, you want to have it expressed a lot. For instance the first version of Golden Rice produced Vitamin A but not enough to matter, it took several years to make one that expressed the genes strongly enough that it made significant amounts of Vitamin A.
> Was it just things we couldn't observe at all without modern scanning electron micrography?
Perhaps also that we couldn't imagine, much less accept, that a dumb semi-random process tweaking bits could, over time, organize those bits into higher level abstract structures. We still mostly talk about evolution mutating genes, where perhaps if you zoom out a little, it's actually working at a higher level of abstraction.
Incidentally, this is the same outlook as some people have today wrt. LLMs - they can't accept the idea that backprop running on a blob of weights representing a simple (if large) graph can start encoding increasingly high-level, abstract organizational structures.
Can't observe and woefully hard to understand. Remember in the 1950's the only genetic disease they could trace to a mutation was sickle cell and that was guesswork. They didn't have any of the cute editing techniques or amplification and sequencing tools. It's a miracle they figured out what they did.
so the thing that makes this complicated is that having non-coding DNA that does nothing for an individual can still be helpful for a population. they essentially serve the same purpose as commented out code that is really common when devs aren't using version control. the comments won't affect the program as it currently exists at all, but they make it so small changes to the code can more easily change the functionality.
Maybe not as much commented as unused. Turns out, there's plenty of that in DNA, and you can force turning it on. See e.g. the bit about snakes growing legs in the video I linked - they still carry the blueprint for legs in their genome, but have it suppressed.
You might enjoy the book Junk DNA by Nessa Carey. Very interesting how complex and interrelated our DNA is. Pretty much spaghetti code.
>> I don't quite trust folk when they say "Oh, that's just there in your body but it doesn't do anything."
If you expand that to "You don't need that" it covers the appendix, spleen, tonsils, wisdom teeth (even incisors can be removed to make room) and probably some other things. I'm in favor of keeping all your parts unless absolutely necessary, as all of these things seem to have at least marginal purpose.
I generally agree, but:
1. They used to yank everyone’s tonsils at any provocation. There was a swing back to trying never to take them. I wish my pediatrician would’ve had mine removed after my nth tonsillitis so I didn’t have to have them out in my 30s. That was fun.
2. Having had an emergency appendectomy, I’m sympathetic to the notion of proactively snipping them any time you happen to be in there anyway. Getting a hernia fixed? Oh hey, let’s grab the appy while we’re at it!
Except the appendix is an important organ. It has a high concentration of immune tissue and supports the immune system in the gut, and it's also a "safe house" for beneficial bacteria in the case of food poisoning or other gut "clearing" events.
It absolutely should not be just nipped out proactively.
Those are all true. However, appendicitis is still the most common abdominal surgery worldwide[0] and lots of people still die of it. It's easy to make the case that someone already undergoing abdominal surgery where the surgeon has ready access to it could have long-term lower health risk by removing it.
If you live in a country with excellent healthcare and you're never far from a hospital, the calculus is a bit different. You'll probably be fine. If you regularly find yourself far away from modern medical clinics, it's easier to defend the idea.
I had appendicitis as a kid. If you've never experienced it, trust me, you don't want it.
[0] https://pmc.ncbi.nlm.nih.gov/articles/PMC9945388/
If you practice good food safety and hygiene (and live around people who do the same) then removing the appendix during unrelated surgeries or even preemptively before long stays at a place without emergency healthcare can be beneficial.
It's a bit of a Chesterton's Fence situation: the appendix is really useful, but for you and me the benefit was much larger 300 years ago than it is today. Today the benefit is small enough that you can remove it with only minor considerations (like being more cautious about your gut microbiome, and having a slightly worse immune system)
Makes me wonder what we'd uncover with systematic longitudinal studies (within the same culture, rather than comparing populations with distinct cultures and genetic bases) on effects of male genital mutilation.
I would expect at least some evolutionary pressure to get rid of unused things in your body. Let's just take the appendix as an example because it's probably the most common "you don't actually need this" thing that people know about.
Some appendixes burst. Sometimes this kills people. Sometimes this happens before that person has been able to reproduce. Wouldn't this cause selection for people who at the very least don't have bursting appendixes (appendices just sounds wrong to my inner narrator in this context), but also for people who have smaller ones. Over time this pressure would decrease but shouldn't it theoretically over many many generations result in smaller and smaller, eventually disappearing, appendixes?
Whether a thing can be selected-out depends on the shape of the fitness landscape in the environment.
For example, appendix-bursts are clearly rare enough and treatable-enough that they cannot be selected-out in modern humans. (But almost nothing can if almost everyone is able to reproduce, and any selection effects will be driven by the number of children which is largely cultural.)
If a thing hasn't been selected out, you can roughly conclude either that:
1. The selection pressure to do so isn't strong. Either few appendix bursts occur in an ancestral env, or they don't disrupt reproduction bc they happen later in life, or are treatable, or other causes of death kick in before the appendix matters.
2. Or, if the selection pressure is strong, there is "nowhere to go" in gene-space that improves this aspect of fitness, within the search-radius. (Which is really equivalent to 1: the selection pressure isn't strong enough to search widely enough)
3. Or there is a stronger selection pressure for it, even if you can't figure out what it is, like the "backup gut bacteria" thing for the appendix. (Which is actually equivalent to 1/2 also: the selection pressure isn't strong enough to find a way to separate the upside from the downside)
I would think so. Who says that's not happening now? It seems reasonable that evolutionary pressure can be strong enough to have a significant impact in 1-2 generations (for example due to the introduction of a new environmental threat) or weak enough to take thousands of generations.
for me, appendix / appendixes (organ) / appendices (to a book) too, just like index / indexes (database) / indices
Can we be sure that we don't need the appendix ?
We used to think tonsils are optional as well, and there seem to have been some studies that find a link between tonsillectomy & Crohn's, Hodgkin's or even breast cancer (from wikipedia).
There surely must be vestigial parts in our organisms, like the one in the article, but more often than not we have no fucking clue how they interconnect with the whole and what their function is.
I think. I'm not a doctor or anything.
Appendix is being appreciated these days as a reservoir of good gut bacteria. So there’s actually probably some pressure to keep it around. Appendicitis is a thing but of course not everyone suffers it. Maybe in the primitive world you were more likely to see your skull meet a rock before that happened in significant numbers of people in the population to the point it affected offspring counts.
Agreed. There is, or at least were, some parts of the body that were only recently discovered and not just known about and assumed to be inactive. It was only in 2015 that lymphatic vessels were discovered in the central nervous system:
https://www.nih.gov/news-events/nih-research-matters/lymphat...
That article is about mice, but they were later found in humans, too.
The Chesterton's Fence of body parts.
https://en.wikipedia.org/wiki/G._K._Chesterton
Man, does THAT sum up the current political climate in America.
There exists in such a case a certain institution or law; let us say, for the sake of simplicity, a fence or gate erected across a road. The more modern type of reformer goes gaily up to it and says, "I don't see the use of this; let us clear it away." To which the more intelligent type of reformer will do well to answer: "If you don't see the use of it, I certainly won't let you clear it away. Go away and think. Then, when you can come back and tell me that you do see the use of it, I may allow you to destroy it."[97]
The Chesterton fence defense (yeah!) doesn't apply.
Did you care about Chesterton when the previous set of fence-smashers went around smashing (much older) fences?
The Chesterton fence argument is that you need to understand why the fence is there. If you do understand it, and still remove it, it doesn't say that's bad.
A lot of this comes from the assumption that our organs each have a single purpose, so if the obvious purpose is not relevant in humans then the organ is useless. But most organs serve multiple purposes.
Take mitochondria as an example.
There has been a revolution in the understanding how this organelle works in the last few years.
https://www.sciencedirect.com/science/article/pii/S089865682...
Evolution works on a different timescale than what science divulgation headlines, and selected lineages to care about how to cross deadly valleys even though they might have appeared rarely. There's little room for baggage.
There is no grand design in biology. If something ain’t broke, evolution ain’t going to fix it. Retina in mammals facing backwards that gives rise to blind spot is one example. The laryngeal nerve that goes all the way down aorta and back up the neck is another
Not exactly. Everything in our body needs energy to maintain itself. It has to provide some value for the energy it consumes, otherwise not having it becomes an evolutionary advantage meaning evolution will gravitate towards it.
What a_c is getting at is that evolution can become trapped in local optima. The backwards retina in mammals is suboptimal, but it's locally optimal - the path from where we are to a better design (like the one in squid) is too long for evolution to hill-climb up to.
Informative X thread on how the recurrent laryngeal nerve path is dictated by having to develop embryos through chemotaxis: https://x.com/culpable_mink/status/1850937701518000383
He mentions that even if you're a giraffe, you have nerves just as long running to the end of your spine, and from your spint to the bottoms of your feet, so the extra length of nerve isn't really a problem.
There is a pathway for every possible configuration. It doesn’t dictate whether a configuration is optimal. Maybe the laryngeal nerve isn’t that bad. But that doesn’t guarantee all anatomy and physiology optimal
Also, if something truly serves no purpose, evolution will allow it to go away.
The classic example is the enzyme needed to make vitamin C. In our primate ancestors that lived on a diet rich in vitamin C, there was no penalty to losing this enzyme. Mutations that destroyed its function were not selected against. As a result, we now can't make vitamin C; the remnants of the gene for the enzyme have been so damaged that there's no path back to the working version.
Eh evolution will certainly try to fix things that ain't broke, indeed it will try to vary just about everything at some point or another. Bad cable management remains because no one survives the intermediate steps between functional configuration A and optimal configuration Z.
Tonsils are a good example of this. New studies are finding that they may be part of the immune system. Anecdotally, I had mine removed as a child due to frequent tonsilitis. As an adult, I suffer from a number of airborne allergies. Most likely a coincidence, but it does make me wonder!
No matter how hard I twiddle the left nipple, I can't seem to pick up Jazz FM.
My grandfather managed to persuade me when I was 4 that beer comes out of man's nipples. Unfortunately, at the time he was supposedly too old for it to happen. And my father was too young. So, I've never seen it in action
Epistemological modesty/honesty is undervalued compared to confident certainty (in my mind at least).
This is not news. People know this. I can move my ears voluntarily, and when I'm trying to listen, I can feel that happening. It's probably half conscious. There is an intuitive purpose behind these muscles, which is to do the best impression of pricking up your ears that some evolutionary predecessor was able to do better.
Whenever I hear a noise behind me this muscle reflexively flexes quite hard, especially if it's a sudden noise that makes me jump.
Yes. It's quite a distinct part of my being startled by an unexpected sound, similar to hairs raising on the back on my neck.
Same. Is this something not everyone experiences or just never really comes up in conversation much I wonder?
I think there's a big difference between "activating" a muscle and "getting utility" out of it. Sure, maybe it activates sometimes, but what does it do? Well... nothing. It's a vestigial structure.
I ... thought this was common knowledge.
I learnt how to wiggle my ears when I got startled by a book falling from a shelf and my ears instinctively "raised". Picture a dog going from "idling" to "alert", with the ears pointing up. It was like that, but for humans.
I then said "Ooooh, so that's how you do it".
There has never been a doubt in my mind that the muscle is connected to "alert, listen closely".
There's a lot of odd stuff we're gradually figuring. Also interesting, some of the hair cells in the ear act as amplifiers and you can hook them up to an electrical sound signal and have them dance around:
https://youtu.be/pij8a8aNpWQ
I suspect the standard explanation for that as given under the youtube video:
> Since the amplitude, and hence the mechanical energy, of airborne sounds is tiny, the cochlea mechanically amplifies the incoming vibrations.
is wrong as it doesn't really make sense from an engineering point of view - if you've already detected the sound to activate the hair cell then that job's done. My theory is they actively damp down the large vibrations so you can pick up the small ones. There's a 10^5 amplitude difference between large and small.
> the cochlea mechanically amplifies the incoming vibrations
Is that even possible in principle? Amplifying requires adding energy, it has to be either provided from somewhere else or redistributed from other parts of the input.
EDIT:
Aha, but apparently this system is not a passive amplifier at all! Per Wikipedia[0], this is an active, electromechanical amplifier, which makes the explanation you quoted more reasonable (if not accurate).
--
[0] - https://en.wikipedia.org/wiki/Cochlear_amplifier but the core observation is also stated in summary here[1].
[1] - https://en.wikipedia.org/wiki/Organ_of_Corti#Cochlear_amplif...
Idk man, survival seems like a pretty blunt selection force for such an intricate mechanism
My ears tire when hearing foreign languages spoken, it feels like my ears keep automatically trying to discern each word as if I might understand them.
Stapedius-mediated phonemic saturation is almost unheard of by most people.
"Huh, we cut through that muscle every day"
-ear nose and throat surgeon
I know how to look hard by squinting my eyes and trying to focus, talk hard by speaking as loudly as I can or smell hard by breathing in as much as I can, but how do you listen hard?
Try explaining in words how to raise a single eyebrow to someone who can't.
Tactile intelligence and semantic intelligence do not overlap
I've gotten at least two people (youths) to be able to raise a single eyebrow by placing their finger on their eyebrows and feeling their muscles activate as they raise and lower both eyebrows. Keeping your fingers on the eyebrow muscles, it's almost like your brain can start to "see" the two distinct muscles. It didn't take them too long (days not weeks, not hours) to be able to raise an eyebrow.
There's probably a biological component to it to, I'm not saying this will work for everyone because it didn't work for my spouse.
Part of the teaching was physical. Hard to do it with words alone
Am I the only one that consciously uses that muscle??
Nope. Came here to find such relating experiences and only found yours.
Quiet batpeople.
So, movies are actually right.
All I can picture right now is a Ferengi.
The angle you tilt your head to, to REALLY listen intently is known as "Mozart's Incline". Honest.
Science around human body movements is in its infancy. Motion capture can't differentiable various muscle group activations, resulting in the same motion pattern. Electric activity sensors are not sensitive enough to capture individual muscle movements. And there are not enough interesting subjects (top athletes, performers etc) available to scientists to improve models and methods.
It's funny because these developments come at a time where a large proportion of the world no longer really uses their body for their living.
I wonder how different our ancestors perceived the world when their survival depended on their athleticism and keen senses. What knowledge and skills were common that have been lost to us now? There have been articles on HN about scientists "discovering" humans can exert control over their pupils and more and more scientists are "accepting" that echolocation in humans is real and learnable.
There are some fascinating stories about kids abducted and raised by wolves - who, when they were eventually found and brought back into human society, showed seemingly "superhuman" senses of hearing and smell. The senses became more normal the longer they spent time in human society however.
Not sure how credible those stories are, but if they are, this would indicate that human senses are a lot more flexible than we believe they are.
One of my favorite examples is the possibility of humans to have magnetoreception.
I'm finding the headline is remarkably annoying.
Evolutionary pressure is pretty brutal to things that actually aren't used - building a muscle takes energy and is one more thing for the body to maintain. I don't see how it is fair to say "thought humans didn’t use". It is always "if it has a use, we aren't sure what it is yet". Nature isn't a perfect architect but the odds are just much better that the use is still to be discovered than that truly useless bits of the body exist.
> I don't see how it is fair to say "thought humans didn’t use".
Did you not learn about "vestigal organs" in grade school?
Maybe consensus has changed lately, but that at least used to be a thing.
They taught us the appendix was one such organ. Now they are thinking it actually has a use and is not at all vestigial.
https://en.wikipedia.org/wiki/Appendix_(anatomy)#Maintaining...
I remember the pineal gland in the brain as well, that was part of why it got used as a source for psychic powers in older fiction.
This was a memorable film which feature it: https://en.wikipedia.org/wiki/From_Beyond_(film)
Based on Lovecraft, so it fits with "older fiction"
What, if you learn about something at school it is automatically true? The same criticism applies there too. They were calling things like the appendix vestigial when it obviously isn't. People made a big deal about how it doesn't do anything and then it turns out it does something. Who'd have guessed. The so-called vestigial organs probably all have uses. I'd have a much easier time believing most of them do than none of them. Otherwise evolution would have done a much better job of weeding them out.
> The so-called vestigial organs probably all have uses.
You’re right that some organs have been labeled vestigial and turned out not to be, but there are other organs that we know are vestigial because they don’t occur in all humans (same goes for other species). Evolution doesn’t weed things out without there being relatively strong effects on survival, and some of these things don’t affect survival so they drift.
This also isn’t binary. There are organs that are still classified as vestigial, but have minor or secondary uses, perhaps enough for evolution to keep them around, or again perhaps because having them doesn’t result in any statistical mortality.
Speculating and/or carrying beliefs that contradict modern evolutionary biologists probably isn’t going to work out. School might not be always right, but it is most of the time, and it’s right more often than no school, right? https://en.wikipedia.org/wiki/Human_vestigiality
> What, if you learn about something at school it is automatically true?
It's a decent indication that people thought it was true.
When I read "humans didn't use", I understand that other animals with which we share close common ancestors still use it. Evolutionary pressure can make organs go into disuse so it makes sense that we end up with unused organs.
A 1% reduction in body mass is a huge advantage evolutionary, especially since rather than being cut completely that mass could be repurposed as more muscle for competing or more fat for lean times. For something in very recent evolutionary history (talking the last few thousand years), yeah sure the pressure might not have optimised a wasted organ out. But for any random organ? Nah, they probably have a purpose and we don't know what it is yet. Otherwise there is a big advantage to removing 'useless' bits. Evolutionary processes do however love little random tweaks and whatnot because they serve a useful purpose in weird edge cases and it is much more likely we're looking at one of them in any particular case.
And the ability to breath fire would also be a huge advantage, but evolution does not seek advantages, it merely keeps mutations that happen to be beneficial. No one has been born with a mutation that has allowed them to breath fire (or if they were they obviously didn't have much reproductive success) and thus we are still unable to breath fire. No one who has been born with a mutation that prevents the development of ear muscles has had especially great reproductive success either.
> A 1% reduction in body mass is a huge advantage evolutionary
That thought fails to explain the wide natural variation in body mass of humans, and within each species on this planet.
Edit: for most species being smaller is a disadvantage. Mates statistically select for larger stronger individuals, and larger stronger individuals are statistically better at killing and defending.
A little study of biology will clear that up. Species inhabit different niches. They have different survival strategies. Each case requires a different optimal point.
Please elaborate, I think you misunderstood me. Are you defending the claim that 1% human body mass reduction is an evolutionary advantage? Your quip about biology should maybe be directed at @roenxi?
I was talking about variation within each species, not across different species. (Edited to clarify) I was talking, in context as a reply to the claim that losing a given vestigial organ would improve (lessen) mortality. Humans, for example, have wide natural variation in body mass, therefore the evidence contradicts the claim that “1% reduction in body mass is a huge advantage evolutionary”.
If a reduction in body mass was an evolutionary advantage, we’d be evolving to be smaller over time. That’s not happening. Why?
In fact, there is an evolutionary advantage in humans to being taller and having more muscle, since these traits are selected for by mates, and are beneficial for hunting.
Evolutionary pressure also would select for not wasting energy on a useless organ.
The selective pressure of small unused organs may be very low and virtually disappear in the stochasticity of natural selection. It may take a long time for such elements to disappear completely
There is only evolutionary pressure on things that affect mortality. Vestigial organs can and do exist because there is no evolutionary pressure on them, because they don’t affect mortality.
[dead]