Your Head Might Be On Sideways

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In your brain the right side controls the left half of your body and vice versa. We still aren't sure why this is, but some scientists have come up with a pretty bizarre explanation: that some ancient vertebrate ancestor was born with its brain on backwards. Or, at least on sideways.
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Опубликовано:

16 сен 2024

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Комментарии : 721

@SaintParallax 4 года назад

Imagine being born with your head crooked, getting made fun of your whole life, then being the blueprint for thousands of generations of different species

@limiv5272 4 года назад

But not living long enough to know this

@euanlankybombamccombie6015 4 года назад

Saint Parallax ....then we would just feel worse than van Gogh....bullied as a kid for your head/hair and not knowing just how much of a feckin Don you actually were when alive!....oh my days just a cruel cruel world

@shanerooney7288 4 года назад

Ah, yes. I commonly imagine having sex despite being ugly.

@spot5890 4 года назад

flounders ;-;

@Stue-e 4 года назад

*laughs in sideways*

@lonjohnson5161 4 года назад

Not every mutation that survives is an improvement. Sometimes it just isn't sufficiently lethal.

@lonestarr1490 4 года назад

But then again, we all have to be descendants of that one single mutated individual (given that the mutation in question is unlikely enough to not happen too often). And there better be some decent amount of reason for that.

@Pit1993x 4 года назад

@rrobertt13 Because it's extremely unlikely that more than 1 individual has had the exact same mutation of its DNA. It's far more likely that it all started with one individual that happened to survive despite this anomaly and managed to pass on its oddity. After its first successful procreation there'd already be more than 1 individual with its mutation that were able to pass it on and change it further but it all most likely started from 1 individual.

@maxximumb 4 года назад

@@lonestarr1490 As Lon said, evolution doesn't need a reason. Any mutation that doesn't kill the organism before it breeds, passes on it's DNA. Once the twist gene mutation happened, that gene would be present in all it's offspring either expressed as a twist or repressed. It's then likely to pop up over time. Maybe a twisted head allowed a wider field of view of predators so that gene when expressed survived long enough to breed, whilst the straight headed died out. Or it could just be the mutation happened just before one the the several mass extinctions and the straight head population were killed off and the twisted lot survived. Some times evolutionary changes give an organism an advantage, sometimes it just doesn't kill the organism before it reproduced.

@annalisette5897 4 года назад

I like that comment!

@64standardtrickyness 4 года назад

Evolution pretty much always has a reason it's just that the reason is not understood or inertia and lack of evolutionary pressure. Yes we have many vestige appendages because we had them early on and evolution is slow to work and or course humans don't have the standard evolutionary pressure. Mutations are rare what are the odds that every nonmutation died while the mutations survived.

@mortimerhasbeengud2834 4 года назад

"Does your nose run, and your feet smell? Then you're built upside down!" -Mad Magazine

@joseb.junior1455 4 года назад

3:13 The editor missed the chance to flip the baby's head and traumatize half the viewers.

@massimookissed1023 4 года назад

Like Tom Tucker's son, Jake.

@clarissarivera8066 4 года назад

😆😆😆 that would've been the best! 😊

@ce4072 4 года назад

The thumbnail already did that before the video even started.

@csweezey18 4 года назад

@MrFr0stycave I AM CALM!!!!!

@madLphnt 4 года назад

@@massimookissed1023 hahah

@g.m.2427 4 года назад

I've always known that i was a bit twisted but i've never realised that i had my head on backwards

@mynameisworld 4 года назад

The question is: can we old folk can keep telling you young'uns to "get your head on straight!" 🤔

@wildoatling 4 года назад

Nice

@BrntToaster 4 года назад

I never noticed that i have a preference hugging to one side. Now i'm going to be aware of it every time. Thanks Michael..

@lonestarr1490 4 года назад

Consider yourself lucky. Because there are people out there - like me - who tend to tilt in the wrong direction, causing confusion and sometimes embarrassment when trying to hug someone ...

@Future_Pheonix 4 года назад

There are a lot of these little preferences, like which leg you tend to lean on more, which hand usually goes on which hip, which leg you usually cross over which etc. Which usually has to do with which side of the brain is more dominant. But this brings up another possible cause.

@heronb.4965 4 года назад

here's another thing that you'll think of everyday: you never sleep on the side of which you lay in bed. you will always turn at least once in bed before going to sleep. i don't remember where I saw it, but it has been true for well over two years now

@billybobjoe198 4 года назад

@@lonestarr1490 That's just Autism my dude. Normal people can instinctively and subconsciously read others body languages and movements and auto-compensate. You can consciously make up for this short coming if you want to. It will still feel awkward to you, but if you're good at it, the other people won't notice.

@csweezey18 4 года назад

@@lonestarr1490 Yeah, I know the feeling. It can be pretty annoying.

@Sehrafina369 4 года назад

Literally the creepiest thumbnail I've ever seen guys, so thanks for that. *shudders*

@novastar3990 4 года назад

You must not have seen much...

@Sehrafina369 4 года назад

@@novastar3990 nope, not a lot of creepy thumbnails cause I don't usually watch/follow things like that. 🙂

@jama211 4 года назад

@@Sehrafina369 So not nope then, you agree that you have not seen much

@mynameisworld 4 года назад

Just creepy? Try flippin' terrifying! 😱 I just got done watching Nexpo, and I go back to the RU-vid home page and woah---- literally made me jump away from my computer.

@mynameisworld 4 года назад

@@jama211 I think her "nope" wasn't to disagree. I think it was an agreement "nope," as in, "you haven't seen much?" "No, I haven't." And by the way, I, for one, HAVE seen a lot. On RU-vid and in person. Worst was probably witnessing a shooting. But that thumbnail with a realistic head turned nearly backwards in a thumbnail format that is usually realistic because it's about science, it was unexpected.

@robotempire 4 года назад

This host should read audiobooks. He’s got the breathing perfect Edit: or maybe the audio engineering is just really good

@Sciencerely 4 года назад

When I've first heard about decussation in a lecture, I thought it was astonishing that such drastic developmental changes are possible considering what can happen if human development deviates slightly. For example, the protein "sonic hedgehog" (yeah, that's the real name) orchestrates many things during development including the width of faces. Only small changes in the amounts of sonic hedgehog makes faces broader or slimmer - in very extreme cases this leads to split faces or cyclopia (which is normally fatal, would love to make a video about that myself). So it's great how well decussation turned out!

@petitio_principii 4 года назад

The further you recede phylogenetically, the simpler the animals were, and therefore they were also more "flexible" in regards to having relatively drastic changes not being deleterious. That's the first time I've heard of such "developmental twist" hypothesis, which to me makes much more sense than some "adaptationist" ideas along the lines that decussation kind of forces an "altruism" between the different brain hemispheres having to take care of the other side of the body, kind of like self-interested conjoined twins that also somehow had control to what one would think is the twin's body. An "evolutionary leftover" of some flatfish-like developmental contortion followed by a sloppy reversal-bu-to-the-wrong-side makes it much more reasonable. But then there are things like some "internal decussations" on the eyes that I don't get. The more I read about it, the more intriguing it gets, apparently there are even ways on how it impacts reading and how reading learning is encoded in the brain.

@semaj_5022 4 года назад

I always look through the comments on SciShow's videos to see your input. Thanks for always having an interesting take on the topic :)

@Gamespud94 4 года назад

Was originally gonna post a comment about how unlikely it seems to me that decussation just happened by coincidence to be such a dominant gene without any benefit... but now I just can't stop thinking about how I can't take a gene that apparently determines face width being called "Sonic Hedgehog"... I mean.. I know there's a lot of ridiculous scientific names out there as people are within reason allowed to name things whatever the hell they want... but... "Sonic Hedgehog"? I just... WHY!?

@Harry-cy5vz 4 года назад

SONIC HEDGEHOG

@KryssLaBryn 4 года назад

@@Gamespud94 iirc it actually has sort of a spiky appearance, hence the "hedgehog" part. And from there, well, scientists are usually huge nerds, so Gonna be kind of hell for students to remember a couple generations after they stop making Sonic the Hedgehog games, though. Have to admit, my own preference is for the "what the thing is but in Latin" naming conventions. Makes it much easier to remember that, say, the stones birds have in their stomachs to help grind up food are called "gastroliths" lol

@johnopalko5223 4 года назад

I knew about the kissing but I never knew about the hugging. Okay, I just did an experiment. I turn my body to the _right_ when I hug. I wonder if this is related to being left-handed. Now I need to write a research paper: _On the Chirality of Hugging._ It should rank right on up there with _On the Rheology of Cats._

@shanerooney7288 4 года назад

We tend to reach over to grab something more often than we reach below something. So our predisposition to lead with our dominant hand makes sense.

@DrJiKentauriuzHero 4 года назад

That's something I would read. I turn my body to the left despite being left-handed. I have not tried kissing before so I dont know how may head would tilt (yes I have not been in a romantic relationship for the entire 26 years of my sad, sorry life).

@uncleartax 4 года назад

Omg turn right to hug!!!! You’re a hugging freakshow lol

@patrickmccurry1563 4 года назад

@@shanerooney7288 I'm extremely left handed but turn clockwise for hugging. I want the side that feels things more strongly to be touching my partner. So I'm a bit skeptical of any of us making conclusions about something this vague and personal.

@shanerooney7288 4 года назад

@@patrickmccurry1563 You, a leftie, turning clockwise is the same as the OP, another leftie, turning to the right. Unless I'm misunderstanding one of you two.

@OneColdMonkey 4 года назад

When I was a kid and they found I was dyslexic, they also found I was right-brained/right-handed. They figured it out because I write with my right hand, but with my wrist curled, the same way a left-handed person would write.

@LobarRobotic 4 года назад

So... you're actually the One to fix us all???? *bows down to the Saviour

@OneColdMonkey 4 года назад

@@LobarRobotic lmao oh god if I'm the new model we're all doomed!

@LobarRobotic 4 года назад

@@OneColdMonkey Everyone, look how humble our Saviour is! Hail OneColdMonkey! So humble and wise! The Saviour of our evolutionary line!!

@Anonymous-sb9rr Месяц назад

I have this too. But I'm not sure what being righd-brained means.

@DrJiKentauriuzHero 4 года назад

Lol. I've always thought my face was abnormally assymetrical like I have some sort of unnoticable birth defect. You wouldn't notice it unless you stared at me really closely. I noticed it while I was looking at the mirror one day and had this feeling that my face was somehow tilted slightly to my left. After watching this video, I now feel a bit more normal.

@WouldntULikeToKnow. 4 года назад

One of my eyes is slightly larger than the other and one eyelid is just a little droopier. I only know this because it makes it a little harder putting on eyeliner 😆

@mariahs1123 4 года назад

I had a friend tease me and would tell me my eyes were uneven. It made me really self conscious about it, but now i know its perfectly normal, which is a releaf!

@Yal_Rathol 4 года назад

everyone is asymmetrical, put your hands together and you'll notice they're not identical, same with your feet, same with your eyes, same with your ears. obviously you'll see your asymmetry better than anyone else will, you see your face every day.

@katiebrobst6901 4 года назад

Michael's voice is so soothing

@ABW941 4 года назад

The more you know about evolution the more you realise that by our standards, the results would be considered a faulty and lazy job.

@absalomdraconis 4 года назад

Software engineering at work!

@francoismorin8721 4 года назад

Hard to believe if you stick to the theory of evolution principals. That means having your head sideways was an advantage for survival that made this first common anscester reproduce more. Most genetics errors are not vable and when they are they often are not transmitted or they become junk dna. I have my doubts.

@ABW941 4 года назад

@@francoismorin8721 It is just not the simplest way to solve a problem since it was done without intelligence. One of the prime examples is the reccurent laryngeal nerve in the giraff, which was used by Richard Dawkins to show that there is no intelligent design. The video should be on yt.

@francoismorin8721 4 года назад

@@ABW941 Intelligent design and intelligent laws may be two different things. I used to be a strong faith belkiever in God has taught in Chritianity. A God that intervenes personnaly in our lives. Then I taught intelligent design coulb be the answer. But then again it would mean some personnal intervention in each creature. Now, and I believe it makes more sense in the end, I sort of opt for the God of harmony has seen by Spinoza and Albert Einstein, but I am more hopeful then Einstein and still leave a margin for some sort of survival of our identity or consciousness after death (very slim chances, but I am open minded). Anyways I believe that the randomness of life mutations does not mean life is not intelligent, but rather that it is functionning by trial and errors, millions of trials and errors until it find the more suitable path. My best argument for that would be in the case of convergent evolution, go read this article about the Tasmanian Tiger and the Wolf phys.org/news/2019-09-evolution-tasmanian-tiger-wolf.html

@francoismorin8721 4 года назад

@@ABW941 ntelligent design and intelligent laws may be two different things. I used to be a strong faith believer in God has taught in Chritianity. A God that intervenes personnaly in our lives. Then I taught intelligent design coulb be the answer. But then again it would mean some personnal intervention in each creature. Now, and I believe it makes more sense in the end, I sort of opt for the God of harmony as seen by Spinoza and Albert Einstein, but I am more hopeful then Einstein and still leave a margin for some sort of survival of our identity or consciousness after death (very slim chances, but I am open minded). Anyways I believe that the randomness of life mutations does not mean life is not intelligent, but rather that it is functioning by trial and errors, millions of trials and errors until it find the more suitable path. My best argument for that would be in the case of convergent evolution, go read this article about the Tasmanian Tiger and the Wolf phys.org/news/2019-09-evolution-tasmanian-tiger-wolf.html

@JavierGarcia-vf7xl 4 года назад

Imagine having your brain on backwards This comment was made by the anti vertebrae gang

@samhansen9771 4 года назад

You're all spineless, the whole lot of you!

@807pranavghandade8 4 года назад

Umm, actually it's..... Ahh never mind

@solar0wind 4 года назад

I'm studying for my exams at the moment (I'm at uni, studying biology), and just yesterday I researched protostomes and deuterostomes (the group we belong to that has switched anatomy like a neural chord that runs along the back instead of the belly) because I held a presentation about it JUST TODAY. I read that one theory is actually that there was a protostome ancestor that swam on its back, and over the course of millions of years the back became the belly and vice versa.

@smurfyday 4 года назад

How would that work with all the internal organs? I can't see it.

@SeeingBackward Месяц назад

Any fighter could tell you the biological advantage of decussation: The same side of the head as the attacking hand is in the more vulnerable position. That makes it advantageous to have the the dominant side of the body, which can mount a stronger attack, controlled from the side of the head that's less likely to be damaged during such an attack.

@wildoatling 4 года назад

I haven’t watched a video in a while. This is my first time seeing/hearing this person explain a concept/theory and I gotta say, I like him. Soft tone, clear voice, no erratic hand gestures and he’s annunciating well. Keep him.

@ArmyGrunt1986 4 года назад

Wtf, I've been hugging wrong my whole life. So thats everyone backs away when I attempt to hug them

@emzu690 4 года назад

ArmyGrunt1986 I have the same problem! People always back up and I either go left or they let me stay on the right! It does feel strange!

@lonestarr1490 4 года назад

You're not alone. The difference for me is just that I've already been aware of the issue, but ever since I have to think about the right direction to tilt in, and thus those tiny moments emerge in the process of initiation of a hug, when I have to contemplate - which is then obviously enough to cause the other person to wonder what's going on.

@sdfkjgh 4 года назад

ArmyGrunt1986: See, I always assumed people backed away because I have a face that's straight outta bogleech.

@darkninja___ 4 года назад

ArmyGrunt1986 Are you left-handed?

@JeffNeelzebub 4 года назад

We want a hug, not a head butt!

@Sweet_Tooth_Art 4 года назад

I'm 27 and I still can't tell left from right 😂

@no3namesalike 4 года назад

I'm 28 and I still have to make an L and a backwards L with my hands to remember left and right. You're in good company, or at least...company.

@mlck24 4 года назад

Me too. I have to tilt my head left then right to orient myself. My driving instructor almost caught me. 😂

@Sweet_Tooth_Art 4 года назад

@@mlck24 I wore a ring on my left hand so I could tell when I was learning to drive

@mlck24 4 года назад

@@Sweet_Tooth_Art will try to do that for tomorrow's driving lesson. Thanks!

@eaterdrinker000 4 года назад

My sense of left and right are fine, but I screw up my cardinal directions (north, south, east, west, etc.) and my orientation within them, all the time.

@jameslovestocook 4 года назад

Girl: *trying kissing me* Me: hey fun fact, our body is actually the wrong way around.

@Life_42 4 года назад

Lmao

@anastrixnoodles 4 года назад

That was mind-twisting.

@mr.boomguy 4 года назад

In short. If it works, it works. Evolution isn't perfect, but if it's good enought, it's OK.

@JerehmiaBoaz 4 года назад

That's not how evolution works. Random mutations affect every part of DNA so if some characteristic remains unchanged over hundreds of millions of years, changing that part of the genome must have very bad consequences for the organism and hence those changes are repressed by natural selection (iow. organisms with the mutation die before successfully producing offspring).

@mr.boomguy 4 года назад

@@JerehmiaBoaz And If those mutations are good enough, they get passed on. But yes, I know of living fosils.

@nikosaarinen3258 4 года назад

It just works

@JustADioWhosAHeroForFun 4 года назад

When you become an Owl

@swunt10 4 года назад

as a lefty I hug to the right. so this might not be a good explanation for the brain thing but rather a left handed or right handed thing.

@InfiniteAnvil 4 года назад

That would explain why I hug either direction. I have one left-handed parent so I got used to doing it both ways.

@emzu690 4 года назад

Mar I’m right handed and I also always tend to hug to the right, it feels strange to see the other person backing up and then deciding which way to go!

@woodfur00 4 года назад

I am also a right-hugging lefty!

@zonyae29047 4 года назад

Emilio Zuniga I’m short so I usually go straight under the arms 🤣

@emzu690 4 года назад

Zonyae Ambrose XD that’s nice!

@HayTatsuko 4 года назад

I enjoy the subtle nod to decussation in Michael's attire. I also enjoy learning a new word. Thanks, y'all!

@deluxeassortment 4 года назад

I think the flipped brain is more broadly called "contralateral organization". Decussation is the specific crossing of nerve bundles, along with chiasmas.

@ENDESGA 4 года назад

Surely this can’t be related to the high-frequency of right-handedness?

@john-paulsilke893 4 года назад

ENDESGA probably much like snail curls, flat fish and cone animals. Probably a common ancestor.

@kassandranna 4 года назад

Ted-ed has a great video about this, where they explain right and left nandedness as a result of competition and coexistance of humans during their evolution. You should watch it

@patrickmccurry1563 4 года назад

Most animals don't have a preference, so no. I think, only highly linguistic animals have a species imbalance in side dominance. Parrots have the language section in the right side of the brain also have a tendency toward left claw dominance.

@cycoekiller119 4 года назад

@@kassandranna What is the name of that video?

@kassandranna 4 года назад

@@cycoekiller119 ted-ed "why are some people left-handed"

@yoshiSBX 2 года назад

Great video, thanks SciShow! Using this to help with my physiology studies, as part of my physiotherapy course.

@LiLi-or2gm 4 года назад

Fun fact: Each of our eyes sends both, a left and right signal to our brains. It's like we actually have four eyes! Also, the book by Julien Jaynes _"The Origins of Consciousness in the Breakdown of the Bicameral Brain"_ is an extremely fascinating exploration of the implications of having two brains to the origins of language and eventually, self-awareness and consciousness.

@LiLi-or2gm 4 года назад

@@existenceisillusion6528 Yes indeed! I have this paper in my collection. Here's a bit of the conclusions: "Despite the above-mentioned limitations, Jaynes’ composite picture of the bicameral mind has had widespread influence and undoubtedly shaped to a considerable extent subsequent reflections on the biological and cultural underpinnings of human consciousness" And another: "Quite surprisingly, this non-unitary concept of the Self happens to converge with some of the findings that have emerged from cognitive neuroscience studies during the past few decades."

@pauldeddens5349 4 года назад

This is the evolutionary equivalent of designing a vehicle or creature inside of a game, realizing you built the entire thing facing the wrong way, and just using it backwards because you put to much effort in to just redo everything

@CarlosBunn 4 года назад

I watched a 4 minute video to learn that our brains are swapped with the controlled sides, because yes.

@redcherry569 4 года назад

The more efficient packing of nerves makes sense. Here's my theory: It's a defensive mechanism, so if the left side of the brain is damaged you don't loose complete control of that side of the body & the brain functions stored there? Great content as always!

@noemierollindedebeaumont1130 4 года назад

Guy talks about heads being tilted to the right, also has head tilted to his right. I also have my head tilted and i noticed that a few years back. It goes along with more stiffness in one side of my neck than the other.

@ElynevanOpzeeland 4 года назад

This^

@caniscerulean 4 года назад

My guess is that the survival of decussation in vertebrates is due to exoskeleton vs endoskeleton. Invertebrates have exoskeletons encasing vital organs, while vertebrates tend to be squishier. With the ventral nerve line running along the generally softer underbelly, the appendages act as a first line of defense. With vertebrates, the spinal cord is protected by the spinal column, while the lower vital organs are basically just wrapped in muscle and connective tissue. Advantage is given for flexibility, but the limbs wrap towards the front for defense. So if your softest, squishiest part is facing one way, it is advantageous to also have your danger sensing part rotated the same direction. (plus it is harder to get to a squishy part if it is pressed firmly against the ground or wrapped in the center of a crunchy ball)

@keep 4 года назад

Me: I'm a science guy, let me experiment about the hug and kiss hypothesis. Also me: Wait, I don't have a girlfriend.

@kaheichan9 4 года назад

Try it with another guy. You are doing science.

@john-paulsilke893 4 года назад

Flat fish like Flounders and Halibut may actually have a common ancestor and that may explain much of handedness and crossed brain body symmetry.

@DESHolden 4 года назад

Hypothesis (from seeing this video, without any other reference) - our bodies evolved involving to fight or flight influences, which is ostensibly shaped to our front & L-R sides but the front being the main effort due to combined senses & reach in the main being forward (while our rear is unguarded unless we turn). Ergo, our L & R sides are relatively vulnerable, compared to our front, & this includes the sides of our head. So, for our brain to respond to a side-on threat that risks being incapacitated, having the controlling side of the brain opposite to the threatened/damaged physical side could allow us to maintain capacity of sufficient ability & duration to keep using the threatened side's limbs & senses or allows for responsiveness to get away from the threat direction. However, the significant flaw to the above is that the brain's two hemispheres are likely not separated enough such that one side would be sufficiently protected/distant from the affect of the other side's trauma.

@JonahPleatherbooth 4 года назад

An old hippie woman once told me that most people hug wrong. And that the best hug is a literal heart to heart

@leevillanueva7432 4 года назад

Off-topic: everytime I see Michael presenting an episode, my heart skips a beat. If you see this, Michael: I love you!

@billysmith5409 4 года назад

This whole left/right flip-flop has had me bamboozled for most of my life. Thank you Scishow!

@blafoon93 4 года назад

That was an awesome scishow! I always thought it was odd that our nerves crisscross like that but I never read about possible explanations. And I studied biology and biochemistry. It's always amazing to learn new things and get a different view on something that has become so ingrained in your brain that you don't even think about it anymore.

@taaotest 4 года назад

I just love this man's voice. So calming. Oh, and I guess the science science stuff is cool too.

@veranet99 4 года назад

I can see how the head-body twist could account for the crossover from the neck down. But what about the neck up? The eyes would rotate along with the head and not cross over as they are.

@LadyCynthiana 4 года назад

If you think about it, most 4-legged animals have their eyes on the top of their head, which aligns with the back of their body. Humans heads tilt down so far that our eyes are on the front.

@SciFactsYT118 4 года назад

Random fact: Surgeons who play video games at least 3 hours a week perform 27% faster and make 37% fewer errors.

@spindash64 4 года назад

Odd, you’d think they’d have less incentive to preserve human life with what they witness online

@Dorsiazwart 4 года назад

spindash64 ooo look at me I’m so cynical

@DrD0000M 4 года назад

I hope they aren't playing "Surgeon Simulator".

@kobaltapollodorus8922 4 года назад

Everyone else: Really? I usually hug to the left/right side! Me: Can't remember the last time I hugged/was hugged, so I can't say for sure.

@sdfkjgh 4 года назад

3:10 Ok, Jack White needs to make a sequel to The Denial Twist and Instinct Blues called The Developmental Twist.

@execration_texts 4 года назад

I misunderstood the information, tried to correct my head position, and now I'm paralyzed.

@KH-mx7bg 4 года назад

Zebra fish are an awesome model organism for research. I looked at some embryos in our lab today right as they were developing pigment. Cool little fish that have contributed so much to science.

@jowarnis 4 года назад

Dat thumbnail..

@craigcorson3036 4 года назад

1:20 "Or maybe it helps us defend ourselves from attacks somehow." Yes. Imagine that you are attacked from your left side, and the attacker manages to severely damage your brain. It would be helpful if you still had vision and motor control on your left side. That would only be possible with a "criss-cross" brain.

@Ixions 4 года назад

Synodontis nigriventris is a species of catfish which naturally swims upside down. The switch from ventricle to dorsal nervous systems in vertebrates may be associated with this behavior and an aquatic environment with a more plentiful surface supply of nutrients. The potential that heads were pivoted rather than folded in this evolutionary process is extremely interesting.

@user-tc5qc4ql8m 4 года назад

there's something deeply upsetting about learning that our brains are like this because an ancestors was born with its head backwards that really makes me understand how chaotic and out of control this whole mess is.

@Ngamotu83 4 года назад

Maybe a time traveler accidentally played Chubby Checker's The Twist hundreds of millions of years ago, and every animal has ever since been going along with it.

@TragoudistrosMPH 4 года назад

It's refreshing to hear science describe evolution as sometimes being what happened, and not always an improvement. Natural selection is where things trend, it isn't a force like gravity.

@buggyboy2849 4 года назад

Ah yes the "superior" vertebrate masters! *laughs in invertebrate*

@fireriffs 4 года назад

I would think there would be advantage in that if you got attacked in the head on one side and it caused some kind of damage you would still be able to move that side of your body to fend off your attacker.

@bonibroco1076 4 года назад

How have we known about this switch for a couple of thousand years? How was it discovered and who discovered it?

@garethdean6382 4 года назад

There are ancient observations that if you stab something in one side of the head the other side of the body goes limp. Galen cut pigs up and found their actual nerve fibers formed an 'X' shape. (Dec-ussation related to dec, 10 which is an X in Roman numerals.)

@HuckleberryHim 4 года назад

@@garethdean6382 Would it go limp? Restricting nervous activity causes the muscles to lock in place, I thought. I was thoroughly confused by this statement in the video. Did ancient cultures really understand the brain well enough to observe this? Galen is not very ancient.

@garethdean6382 4 года назад

If you sever the connection between a brain and a muscle the muscle will generally relax; a signal is needed to make it tense. This is why strokes can be detected by a person's face going loopsided and why the limbs of those in wheelchairs aren't rigidly locked in place buy ragdoll-like. Certain situations WILL cause muscles to lock be it due to bacterial toxins (Lockjjaw) or the opposing muscle going limp. Humans have known basic facts about the body for some time, but this si not nearly the same as understanding the body in any way. It has been well known since antiquity that one of the quickest ways to kills someone is to damage their head and when evil spirits needed to be let out, it was the skull that was drilled into. Yet the idea that the BRAIN was the seat of consciousness is far more recent. (After all, if you stab the heart a person dies too right?) Indeed reliance on animals is responsible for some long-lasting gaffes; Galen based the number of teeth he said humans had on pigs. So it's been known for some time that stabbing animals on the right side of their head can collapse the left side of their body but what that actually MEANT outside of 'Well now isn't that interesting?' took a lot longer to discover. Indeed it was sometimes dismissed as yet another thing ancients got wrong, it certainly SOUNDS suspect.

@heretic124 4 года назад

Best thumbnail ever!

@beskamir5977 4 года назад

Cool! I was just chatting about this earlier today although I question why/how such a flaw would be successful enough to take over like it had and I'd like to see a more functional explanation for this bug, or rather unexpected feature.

@evelynlamoy8483 2 года назад

what, fundamentally, is the difference of the head turning 90 degrees right, and the body turning 90 degrees left? Since they exist relative to each other I don't quite get what differentiates the part and direction. To me it seems like that would just be the head turning 90 degrees twice

@DrD0000M 4 года назад

No, God spilled coffee on the Adam prototype and had to wring him dry.

@smurfyday 4 года назад

There's no need for god in this hypothesis.

@darrylarsenault5005 4 года назад

thank you patrons

@shannonlove4328 4 года назад

It’s because in rectilinear organism eg flatworms, fish, you turn away from a threat by contracting the muscles on the opposite of the body where the threat is sensed. So if an organism sees an approaching threat in the right sensory area it needs to activate muscles in the left side of its body to bend away to begin to move away. A simple linkage from an eye that detects motion to muscle on the opposite side that contracts is all that is needed.

@daniellezepess 4 года назад

What I'd like to know is why do snail's shells spiral in the same direction? On a recent nature hike, I collected a dozen or more shells of different sizes and coloring. While cleaning them, I noticed they ALL twist the same way.

@lucaspinto5549 4 года назад

This means if you are a front sleeper, you are actually a back sleeper, and if you are a back sleeper, you are actually a front sleeper. What a realization.

@mismismism 4 года назад

Watched this and now I can't stop imagining us as giant shrimp with eyes that actually face directly up, standing upright.

@jakedowman-french3205 4 года назад

Why am I finding this so hilarious?!

@scottmacs 4 года назад

It's hinted at in today's episode of SciShow Psych, but there's an even weirder thing about the connection between brain and body: the left half of your retina in each eye sends signals to the right hemisphere of your brain, and the right half of your retina in each eye sends signals to the left hemisphere of your brain. BUT, the muscles controlling eye movement are still controlled by the hemisphere on the opposite side of your head!

@code0303456 4 года назад

You can fix longer wires in a mirrored setup, thus giving More elasticity AND shock resistance to the brain

@KeyoUFP 4 года назад

I enjoyed this a lot, thank you.

@KapilKumar-sw8lo 4 года назад

If someone was with head twisted. Then it must have given him some advantage. That's why it's genome is naturally selected not eliminated.. Simple we have to find an advantage of twisted head... That's all it takes.

@siobhanmulvey 4 года назад

Kapil Kumar i think humans have found the “advantage” wouldnt you say as the dominant species on the planet. I theorize it’s something to do with perception of reality and actually why humans can be so ruled by their ego/mind alone vs connecting mind to heart/soul etc... bc world domination coupled w world destruction isn’t really such a great advantage after all..hard to study that but I’m sure it’ll happen someday if scientists are this far along already. It’s cool stuff👍🏼

@KapilKumar-sw8lo 4 года назад

Yup it can be true... But I am talking about something scientific/biological advantage.

@chelsey8737 4 года назад

I love being so early that I get the notification while already watching the video

@bananabimb0 4 года назад

He said ‘developmental twist’ like it was a dance move or something

@mynameisworld 4 года назад

That thumbnail is terrifying. [shiverrrrrs]

@blueai5022 4 года назад

That mildly unsettling thumbnail will probably visit me in my dreams tonight.

@petitio_principii 4 года назад

Maybe early on in vertebrate evolution, the common ancestor was kind of like a flatfish, then. Unlike rays, who lie with their abdomen at the ocean floor, flatfish lie at their side, and their head is contorted in weird ways to kind of improvise being a ray. Maybe a flatfish-like ancestor ceased being flatfish-like thing and then readjusted it in a way that's also weird and wrong, rather than the simple reversal. And then all vertebrates are descendants of such bizarre thing.

@xJabZz 4 года назад

Thanks for this video... Fascinating

@GamerFreak-jf3qq 4 года назад

My whole point of view just got turned upside down this literally blew my mind. Ow my head hurts

@Ish96973 4 года назад

Love you sci show!

@7bombarie 4 года назад

Great sweater for this topic!

@ikbintom 4 года назад

Could it be that the brain halves being swapped has the advantage that there are nerves crossing each other, enabling or improving communication between the two hemispheres?

@lonestarr1490 4 года назад

Wouldn't that cause interference instead?

@fegolem 4 года назад

Situs inversus is probably completely unrelated but would be interesting to see how those people are flipped and flopped with decussation.

@regular-joe 4 года назад

Mr. Aranda has transitioned from a being a professional, to being a natural (I know that's a contradiction, but it still feels accurate!). He's always been a pleasure to learn from, and now even more so.

@lyainaquinn2703 4 года назад

The idea of it being a genetic mishap that just became dominant and normal actually makes a lot of sense. If you think about the genetic disorders that somebody can be born with that just because they have them, they can pass them on to their offspring. It's kind of the same thing.

@Tokyo_Sword 4 года назад

Very cool! Never thought about this!

@brianmorse8811 4 года назад

Look at flounders that's a fish with it's head on sideways.

@guytheincognito4186 4 года назад

I'm pretty sure we only tilt our heads to kiss because our noses would otherwise be in the way. It's also easier to hug each other when our heads aren't in the way. There's simply not enough space head on without tilting our heads backwards.

@chrismobile422 4 года назад

Your voice is so soothing

@davidkupersmith1626 4 года назад

This begs the question: why are our brains split into halves in the first place?

@billybobjoe198 4 года назад

Same reason you have a seam on your taint.

@budmeister 4 года назад

so is left-handedness an even more mutated form of this, or did I revert to how I should have been?

@azmanabdula 4 года назад

Work of the devil or something : P Lucky to be born this millenia ey

@dawntompkins6427 4 года назад

When I was in Kindergarten my teachers tried to make me right handed... Yes, that was in 1975!

@DrD0000M 4 года назад

Left-handers are the only ones in their right mind...

@Lamarth1 4 года назад

Crossing over pulls it together tightly. Without the cross the hemispheres of the brain could separate, either within an individual or from genetic drift. Either way it's inefficient. Presumably less efficient than crossing over, which definitely has its own costs.

@kraneiathedancingdryad6333 6 месяцев назад

"if the left side of the brain controls the right side of the body, then left handed people are in their right minds..." Used to have this on a coffee mug.

@firstlast-cs6eg 4 года назад

3:10 I'm not sure what you're talking about with the baby, xir head is tilted, not the face.

@empathyisonlyhuman7816 4 года назад

The asymmetries we feature in our faces would seem to be a means by which we can more easily identify individuals within groups. If we were all perfectly symmetrical we would only have relative feature size and shape to make such determinations. Also the degree to which our faces return to near symmetry can be a way for us to determine genetic health when choosing a mate. As far as a competitive advantage goes consider the scenario of trying to fend off an attack from a predator attacking from the side or from behind with our heads turned sideways to try and monitor them. If we sustain an injury to our head/brain on the side of the attack. It would then prove advantageous that we are wired in such a way that our eyes are controlled by the side of the brain furthest away from said attacker. Thus increasing our chances to survive. Although honestly if you've sustained brain damage from an animal attack, those chances are probably pretty slim. As is the likelihood that you would then go on to breed and pass on those advantageously twisted genes to offspring. But hey, every little bit helps.

@makyx4303 4 года назад

Maybe the part about the spinal cord being in the back because of this is the advantage here

@billybobjoe198 4 года назад

Yeah it makes your more vulnerable area in front of you, making it easier to protect from sneaky types, but more in the line of fire for head on confrontation.