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Craniopagus Twins Share a Brain and See Out of Each Others Eyes
- Knufen 9y agoWith the fear of sounding rude, this is incredibly cool. In the hope we have some neuro experts here on HN: 1. When the article says they can switch to self control, does that mean one brain can control 2 or more people? 2. Does learning behaviour stem from the problem of limited brain resources as it is shared between 2? 3. Can they assume control of the other persons body, and control it simountanously? Thank you in advance Edit: Formatting
- Retric 9y ago3) They can control a subset of the other persons limbs. Seeing out of 3 eyes seems like a much stranger sensory system. It's not going to simply extend to a wider field of view because someone else is controlling the focus.
- 35bge57dtjku 9y agoIsn't focusing done automatically anyway?
- loa_in_ 9y agoI can do it consciously but also don't have to, so... hybrid?
- chacham15 9y agoIs there even just a singular focus? Normally, both of a persons eyes are facing a singular direction which makes a large area of shared vision between the eyes (which allows a focus point anywhere in that field of vision). But with eyes which are pointed in a different direction this seems less likely. Does anyone have more info?
- Swizec 9y agoI often wonder how birda do this (because I have one at home). Their eyes are on the side of their head, pointing in almost completely opposite directions. Yet they’re able to accurately land on things and generally exhibit behavior that indicates they have pretty good 3D vision. Then again my bird often sticks his foot out to step on my finger when the finger is still an inch away. So maybe not as good at depth perception as humans.
- return0 9y agostrabismic people develop active mechanisms to inhibit the opposite eye to avoid / reduce double vision. in the end no matter how many eyes, what matters to the brain is to see something useful, so it will try to learn to suppress confusing information.
- JohnBooty 9y agoI have one normal eye and one eye that has no lens, so I only see vague shapes and colors in that eye. There's no shared focus, per se. (The bad eye literally can't focus at all) I don't typically "pay attention" to the bad eye. Usually, they are "separate" and I ignore the bad eye. Sometimes I have really funny lapses in depth perception. Driving at night when the road is wet (and there are lots of weird reflections) is particularly tough. I can't see 3D movies... mostly. Sometimes that magical 3D effect kicks in for a second or two. When it happens, it's pretty cool. Then it goes away. haha. But, my brain does seem to assemble information from both eyes somehow. I can actually play most sports pretty well. I'm pretty decent at softball and tennis. I also avoided a serious car accident once thanks to that shitty eye. Was nearly broadsided right in the driver's door by somebody on my "blind" side, but that eye alerted me to an oncoming car (jackass running a red light) approaching at fairly high speed. She sheared my front bumper clean off (instead of plowing into my door, possibly killing me because it was a tiny little sports car with little side impact protection) because I hit the brakes at the last fraction of a second. I would wager that the conjoined twins' experience may be something like this. (Obviously, with more eyes involved)
- a_rahmanshah 9y agoInteresting points, John. Would like to read more about your experiences. Are you anywhere on the interwebs?
- JohnBooty 9y agoI'm nearly blind in my left eye (was born with a cataract; lens was removed at an early age before lens transplants were a thing) and I think I perhaps experience something similar. My vision isn't really integrated between the two eyes. It's hard to explain. I "think" with my right (good) eye. But then I also sort of have this auxiliary eye, my left eye. I can just see vague shapes and colors through it. It's just like this... separate camera or something. I can basically pay attention to one eye or the other; they're not really "together." Now obviously, unlike these twins, I don't have another person controlling it. But, I wonder if their experience is similar to mine. Like they have their "primary" eyes and then also this separate disconnected set of eyes they can pay attention to if needed/wanted.
- PhasmaFelis 9y agoI have normal vision (with glasses) in both eyes, but I also have strabismus, that is, one eye turns inward a bit; so rather than seeing double, I use one eye at a time, and can switch from one to the other voluntarily. I just get peripheral vision from the "off" eye. I don't miss the depth perception much, but it does mean I get nothing from 3D glasses. With the modern polarized kind I can at least wear them and watch the movie normally; with the old red/blue kind, the whole movie would be red or blue depending on which eye I was using.
- deleted 9y ago[deleted]
- Brockenstein 9y agoI've experienced something similar. I kind of think that the other eye is still working and providing some depth perception, it's either that or after lifetime of single eye dominance/usage you just adapt and become very good at estimating and judging depth and distance. In my case never having normal vision, I don't really know what I am missing, if anything.
- PhasmaFelis 9y agoYeah! I did some reading and apparently binocular depth perception is the least important kind, and only works out to about six feet anyway; past that there's not enough parallax between your eyes to get any useful info. Judging distance by an object's surroundings is the most common way of doing it even for people with normal vision.
- SomeStupidPoint 9y agoAs for 3, I too am curious: the article made it seem like they normally do a 3-1, 1-3 split on limbs but can each do 2-2 if they want. From a control theory standpoint, that make sense -- you have one person focused on arms and one focused on legs, instead of an even split. (Probably not so different from being right or left handed.) Is this accurate? Also interesting: the one that controls more arms is the outgoing and high-strung one, while the one that controls more legs is the quieter and relaxed one. It seems unlikely that these facts are uncorrelated, though the causal relationship is anything but clear. Incredibly, in an article full of pictures, they never actually tell you which twin is which and only address them as a unit of 'twins' in descriptions, which seems incredibly rude and depersonalizing to Krista and Tatiana. (Or, alternatively, never mention that the twins prefer to be spoken of as a unit -- which is itself an incredibly interesting fact.)
- Chris2048 9y ago> It seems unlikely that these facts are uncorrelated Why does it?
- SomeStupidPoint 9y agoWell, in a sample size of 1, it doesn't make a huge amount of sense to discuss correlation -- the two facts both happened, and so have 100% correlation on that sample size. (But this is a basically useless statistic for making any inferences.) The question was if we expect, given that it happened together here, we'd see it happen together more than random distribution would predict -- that is, that we see personality differences align with a split in limb control. Since they're both changes in the manner in which one interacts with the world, and my experience of the world changes in subtle ways when I, eg, use my left hand for certain tasks or sit in certain postures, I just find it unlikely that the alignment of limb control and personality are unrelated.
- return0 9y agoThere is not a lot of literature about them, but from what i found their thalami are connected or fused together. Since thalamus is the crossroads for many sensory inputs the senses of one girl can pass on to further brain processing regions of both brains , e.g. their eye signals diverge and reach both girls' visual cortices. 1. Each brain controls more limbs than usual, but brains are plastic and can learn do that. It seems they have separate "personalities" however and they recognize themselves as different persons. So they don't "control" each other's consciousness although they seem to be able to communicate thoughts (not clear how) can control the limbs of the other, and can see what the other sees (e.g. with closed eyes, they can see what the other girl sees). Whats fascinating is how one of them can manage to override the movement signals coming from the other. Surely further examinations during their life will show how action initiation/inhibition happens in their brain. 3) It seems no, they dont control a limb simultaneously. They seem to be able to cancel the signals from the other person, presumably because their personal signals are much stronger (possibly because they have learned over time to do that ) or they have developed some mechanism to inhibit sensory signals from the opposite brain. This may be happening already at the level of thalamus where they are connected. Since their arms can possibly be controlled by both brains through the thalamic connection, i wonder if they can train themselves to use primarily the opposite person's limb, e.g. hand. It might be possible since the wiring is already there - it seems to only require sensorymotor traning. 2) I suppose you mean they have some kind of learning problems. But not really, people can learn and have normal IQ with much much less brain than what they may be allocating to the opposite body. And it's not even clear that they do that. They essentially share a thalamus but not much else , and even so, they dont seem to have less total thalamic mass than they would have separated . Also , thalamus being a relay rather than a decision taking region, it doesnt seem it would affect their intelligence too much. - http://ojs.library.ubc.ca/index.php/ubcujp/article/view/2521/182422 http://ojs.library.ubc.ca/index.php/ubcujp/article/view/2521...
- evanb 9y agoAn amazing long-form article on these twins from the NY Times: http://www.nytimes.com/2011/05/29/magazine/could-conjoined-twins-share-a-mind.html http://www.nytimes.com/2011/05/29/magazine/could-conjoined-t... And a previous CBC documentary is on YouTube: https://www.youtube.com/watch?v=WKwT1Ol3nY0 https://www.youtube.com/watch?v=WKwT1Ol3nY0
- Lambdanaut 9y agoFrom a general ai perspective, these girls show us the possibility of having multiple self-iterating recursive identities share the same physical and mental resources. From a philosophical perspective I applaud Mother Nature for spitting on our idea of limited identity in such a compellingly materialistic way. The Ship of Theseus is a good wikipedia search for a thinker's first thoughts about identity. And from a human perspective, these girls will show us the struggles and triumphs of two individuals pioneering so far from the central finite curve of human experience, and with such a supportive mother like that, I believe they will do it in spades.
- SomeStupidPoint 9y ago> far from the central finite curve of human experience Do you mean anything in particular for this, or are you appropriating a TV show phrase to mean "unusual"? (Just pointing out that the 'central finite curve' is something that has meaning to Ricks but isn't really a stand in for 'usual' in any meaningful sense in the context of the TV show -- I'd hate for what's potentially a cool sci-fi idea to turn into a euphemism for "the shell of a high dimensional normal distribution".)
- StavrosK 9y agoI don't know about the OP specifically, but I generally dislike that sort of writing. It uses underspecified concepts in an attempt to sound smart, but all it does is fail to convey much meaning. Whenever I come across it, I think "this person wanted to say something smarter than they could, so they dressed it up in smart-speak".
- datawarrior 9y agoDunning-Kruger https://en.m.wikipedia.org/wiki/Dunning–Kruger_effect https://en.m.wikipedia.org/wiki/Dunning–Kruger_effect
- trentmb 9y agoTurgid prose
- hacker_9 9y agoWow what an incredibly difficult way to live, even stranger that the person you share a brain with you will never physically see with your own eyes, because of the join angle. Hopefully one day scientists figure out a safe way to separate them.
- rayiner 9y agoYou can never physically see your own face either.
- hacker_9 9y agoYes but your face is your own.
- narutouzumaki 9y agoI think you just low key blew my mind.
- deleted 9y ago[deleted]
- averagewall 9y agoWhy separate them? It sounds like they're so deeply interconnected that it would be a destructive as separating your own arm from your body or having a lobotomy. All humans have difficulty living. We have to walk and eat and sleep and can't ever stop breathing or we'll die. These girls just have it different. Maybe harder but since they haven't experienced any different, they're probably not too fussed, just as we don't hope to avoid having to breathe all day long.
- dotancohen 9y ago> Why separate them? I'll tell you the real answer, though nobody wants to admit it. Sex. Children have no expectation of privacy, but adults do. One of them may want a boyfriend, or a child, or even just an orgasm. Maybe she'll just want to masturbate. At that point the children are very likely to _want_ to separate. Knowing if that is a possibility may be important.
- vbuwivbiu 9y agoin the video it was interesting how they found it more difficult to see through eachothers eyes than to sense touch, and futhermore some kinds of seeing were easier than others: they found it easier to identify colours than shapes. Is this because only certain data is transmitted across, or because they're not conscious of some information ?
- evan_ 9y agoI’m fascinated by the idea that they can apparently communicate using their connection- maybe that’s the mechanism by which they can share limited visual information. I want to know more about their shared inner dialogue.
- lostmsu 9y agoMy guess would be, that channel is limited, and vision requires much more data.
- marci 9y agoMakes me think of the CGP Grey "You are two" video: https://www.youtube.com/watch?v=wfYbgdo8e-8 https://www.youtube.com/watch?v=wfYbgdo8e-8
- saladeen 9y agoHAX!
- kensai 9y agoI wonder why they are considered two different persons at this point. I am not entirely sure the justification of separate identity here should be the two obvious separate "bodies" (gastrointestinal tracts, limbs, etc)! All that matters for the same identity to me is the brain. If one can read the thoughts of the other so easily, in my book it is the same person. Disclaimer: am resident in Neurology with a background in Anatomy
- goodcanadian 9y agoIt would appear that they perceive themselves as separate. They don't simply share a brain; there seems to be two of most structures. The brains are, however, highly intertwined.
- kensai 9y agoPersons with Split Brain (to the Corpus callosum) can perceive their right part of their body different from the left. Schizophrenic and other highly psychotic patients can have multiple personalities. They still seem to have ONE thalamus and that says a lot about their ability to perceive each other side.
- goodcanadian 9y agoI could be reading it wrong, but the article seems to indicate that there are two thalamuses (thalami?), but they are connected by a bridge. What this means in a practical sense, well that is above my level of expertise.
- kensai 9y agoWell, technically you have two thalami (two halves).
- teawrecks 9y agoThat's the interesting part, did the people raising them condition them to think they were two people? If they had treated then as one person, would they behave like one person? The brain is amazing and super weird.
- lolc 9y agoThey have their brains fused together and can still walk and talk? The flexibility of the growing brain never ceases to amaze me. It shows how robust the whole process of growing from a single cell really is. A human can grow in uncountable ways. Given how the twins share sensory inputs, I wonder how memory and imagination works for them. As they "hear" each other thinking, do they also share common memories? If one remembers a scene, will the other remember it the same way? Or will it have to be narrated between them? When one reads a book, will the other get the story? I would guess so. But will they share the imagined parts, or will they imagine the scenes individually?
- radicalbyte 9y agoIt's extremely rare though; the article mentions that the vast majority of such twins die within the first 24hrs.
- erasmuse 9y ago>do they also share common memories? Indeed! The way I see it, identity derives from memory. So to the extent (if any) that they share identical memories they are strictly the same person. Beyond that I would guess there may be some (false) identification with behaviours of the other twin, in a manner redolent of Gazzaniga and Sperry's famous split brain experiment: https://physics.weber.edu/carroll/honors/split_brain.htm https://physics.weber.edu/carroll/honors/split_brain.htm
- dingo_bat 9y agoThat they can "talk" to each other in their minds is very interesting to me. I've always wondered whether as humans our experiences are internally similar or not. Do you see my green as red? And so on. But if these girls can understand each other's thoughts that indicates that thoughts are similar. It means they share the same internal logic. Really this could be a good evidence to support the idea that we all think alike. I hope they grow up and their brains are able to mature normally. They will probably always have to share the body though, sadly.
- scott_karana 9y agoI wish there was more info on this alleged ability. It shouldn't be hard to show only Tatiana a picture of a number/person/etc, ask her to think about it, and see whether Krista can tell. Somehow it doesn't add up with the rest (shared motor abilities through the thalamus), and sounds more like the poetic but bogus claims that many twins make about one another.
- avh02 9y agoit's a little difficult when they can see out of each other's eyes. granted one of them can only see out of one of the other's eyes, it's still difficult and probably so unique/case-by-case that it would be difficult to come to any conclusions
- scott_karana 9y agoTrue. Or limb taps would work instead, since nether have control over all of them.
- PeterisP 9y agoSince each of them has a "non-shared" eye, testing this is kind of straightforward, we can retry the same experiments that have been performed for split-hemisphere patients (where the left-brain personality has access only to the right eye and vice versa).
- osullivj 9y ago
- ygggvhh 9y agoThis is a monstrosity. It’s not the 19th century anymore, we can now see this sort of thing a mile off. Why was the pregnancy allowed to continue? The obstetrician should’ve killed them both, that’d have been the humane approach. I bet he just wanted to see if he could pull it off. In before downvotes: this opinion is based on first person experience.
- namlem 9y agoThis is incredible. As we approach the technological capability of direct brain-to-brain communication, cases like this serve as an example of what is in store for us. Our brains are in some sense already multiple consciousness that communicate and collaborate with one another. It could be that connecting to other minds is more natural than we might realize.
- xenadu02 9y agoI think the same thing; this seems like the best evidence we have to date that given sufficient technology it should be possible to communicate in thought between two people. I’d imagine any such system would have a learning curve as each brain figures out the patterns but it seems there isn’t any fundamental difference that makes each person’s thoughts unintelligible. (Granted, as siblings one could argue their thoughts would naturally tend toward being intelligible but it seems too early to know the answer to that question)
- jstanley 9y agoPerhaps literal "thoughtcrime" could become a reality some time soon.
- inetknght 9y agoAnd you think that would be a good thing?
- Asraelite 9y agoBeing joined from birth, any and all memories and experiences formed in their brains that could be shared were shared, and so they would have similar associations and mental pathways formed based on them. While it may be possible to learn and figure out patterns from someone else that you were connected to, I think it would be immensely difficult. You may have to learn the whole world from their point of view from scratch for any mental relations they communicate to have any meaning.
- failrate 9y ago
- trungdq88 9y agoIncredible. I can't wait to see the twin grow up, become doctors, study the human brain and give a TED talk about their discovery.
- ars 9y agoThat would be amazing, but unlikely, since they were described as having lower than normal IQ. Watching the videos makes that obvious as well.
- timthelion 9y agoThat doesn't need to mean much. IQ tests are basically meaningless for their complex experiences.
- ShannonAlther 9y agoMeaningless insofar as that goes, but being fairly clever is necessary to become a physician.
- rhizome 9y agoIf this is the thread where we express our desires for their future, I myself would like to see them make movies or write books. Neurology would be good too, though!
- yters 9y agoIf two minds share the same brain, this means the brain is not the mind.
- BatFastard 9y agoIts just means it can multitask
- _jal 9y agoWho knows what it really 'means'. (And meaning, at least as represented by posters here, seems to vary a fair bit based on oxen ownership.) It seems to indicate that both concepts are more fluid than feels comfortable. To some extent, it feels related to bandwidth/latency/maybe the direct linkage and chemical interaction between brains - as that increases, the boundaries become blurrier. Peter Watts had great fun with this idea in Echopraxia (http://www.rifters.com/ http://www.rifters.com/ ).
- Fej 9y agoTitle is misleading. There are two brains connected by a bridge.
- OvidNaso 9y agoThe computer is not the program.
- Mz 9y agoI actually find articles like this fairly upsetting to see. Presumably, it hits some nerve for me in terms of wanting to have a full and "normal" life in spite of my genetic disorder. In some sense, I can pass for normal in a way that conjoined twins cannot. In another sense, no, I will never be normal. The degree of social friction I face over that fact is more problematic in some ways than the physical limitations. Conjoined twins are so obviously and undeniably different that I just cringe at the idea of the social impact. It very much strikes me as "Hell is other people." I hope their social experience is more positive and supportive than I imagine. A couple of dead comments suggest conjoined twins cannot have a sex life. So, I will just post this here: Determined to live as normal a life they could, Chang and Eng settled on their small plantation and bought slaves to do the work they could not do themselves. Using their adopted name "Bunker", they married local women on April 13, 1843. Chang wed Adelaide Yates (1823-1917), while Eng married her sister, Sarah Anne (1822-1892). The twins also became naturalized American citizens. The couples shared a bed built for four in their Traphill home. Chang and Adelaide would become the parents of twelve children. Eng and Sarah had ten. However, Chichester disputes this number of children, stating Eng had 11.[11] After a number of years, the sisters began to dislike each other[12] and separate households were set up west of Mount Airy, North Carolina in the town of White Plains. The brothers would alternately spend three days at each home. https://en.m.wikipedia.org/wiki/Chang_and_Eng_Bunker https://en.m.wikipedia.org/wiki/Chang_and_Eng_Bunker
- mikestew 9y agoA couple of dead comments suggest conjoined twins cannot have a sex life. My wife and I were discussing that aspect just this morning as we discuss the young ladies in this article, what with Chang and Eng not letting it slow them down much. Given the age of the girls I find it a bit creepy to contemplate, but I’m curious what other pieces of anatomy are wired to both brains. Hopefully they work it out, and I suspect they will. I’m confident that the lives of Chang and Eng were not roses and unicorns, but if a couple of Asian guys can make a life for themselves in North Carolina in the 1800s, and conjoined twins to boot, I thinks these girls have a good shot. As a side note, “Siamese Twins” might be out of favor, but the term originates with Chang and Eng, who were from Thailand, formerly known as Siam.
- 9y ago
- timthelion 9y agoMy neck hurts just looking at them. I hope they aren't in pain
- kowaraj 9y agoThey have a "read"-access to each others thoughts. Also, they have a "write"-access to each others motor areas. The question I cannot stop thinking about is whether they have a "write"-access to each other thoughts??? Can one of them MAKE THINK the other of something different the other being thinking of? The "self" by Damassio was a self-as-process plus a self-as-object... How can one of them think of herself, if another one is thinking by her mind about something different at that moment.... hmm. No I am lost. Anyway, what would be a "self" in their case?
- deleted 9y ago[deleted]
- BackPropagate 9y agoTwo girls, one _Kopf_
- netsec_burn 9y agoWOW This is incredible! How come this isn't on every main media site? I have so many questions! Are both vertebrae connected to the same brain? They have to be. How can they have different personalities?
- cholmon 9y agoDo they share the same dreams? Can one be awake while the other is asleep, and if so, can she experience the dream, or parts of it, while being fully conscious?