
Craniopagus Twins Share a Brain and See Out of Each Others Eyes - Osiris30
http://www.cbc.ca/cbcdocspov/m/features/the-hogan-twins-share-a-brain-and-see-out-of-each-others-eyes
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namlem
This 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.

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andy_ppp
No, this isn't going to work like that; these girls have had incredible levels
of plasticity in their brains to be able to accommodate each other's functions
in ways that are difficult for anyone but them to comprehend.

Take for example the case of people who have never seen from birth and are
given sight through retinal implants; they can see colours and images and
patterns but their brains can make no sense of the input - they sense no
depth, shapes, relations between words and images, shadows meaning three
dimensionality, etc. etc. that we all take for granted. Those neurones have
been put to alternative use already and in some ways you really can't teach an
old dog new tricks.

~~~
BearGoesChirp
I think one of the simplest ways to illustrate this is with sounds. Humans who
spend their early years in an environment devoid of certain sounds lose the
ability to differentiate those sounds. The classical example that many seem
aware of are Japanese speakers who have trouble distinguishing l and r sounds.
Every language has some sounds missing, and so any given person should be able
to find two sounds they can't distinguish unless they were raised in a multi-
lingual household from birth which covered all the sounds.

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Knufen
With 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

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Retric
3) 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.

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chacham15
Is 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?

~~~
JohnBooty
I 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
Interesting points, John. Would like to read more about your experiences. Are
you anywhere on the interwebs?

~~~
JohnBooty
I'm flattered! I don't have much of a web presence these days but feel free to
use my contact info in my profile or reply here if you have any questions.

As far as I know my experiences are fairly typical for people in my situation
though; I'm not sure I have anything unique to say. =)

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evanb
An amazing long-form article on these twins from the NY Times:
[http://www.nytimes.com/2011/05/29/magazine/could-
conjoined-t...](http://www.nytimes.com/2011/05/29/magazine/could-conjoined-
twins-share-a-mind.html)

And a previous CBC documentary is on YouTube:
[https://www.youtube.com/watch?v=WKwT1Ol3nY0](https://www.youtube.com/watch?v=WKwT1Ol3nY0)

~~~
canjobear
Fwiw I didn't find the NYT article had a lot more interesting stuff beyond the
CBC article. It looks like it was written before they knew as much about the
twins.

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lolc
They 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?

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erasmuse
_> 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)

~~~
mlevental
redolent means to smell of. you mean reminiscent

~~~
erasmuse
Shouldn't you begin your sentences with capital letters? :-)

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dingo_bat
That 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
I 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
it'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

~~~
PeterisP
Since 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).

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kowaraj
They 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?

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Mz
I 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)

~~~
fastball
I feel like conjoined at the hip is a bit different from conjoined in the
brain.

~~~
PhasmaFelis
Purely from a logistical perspective, I feel like joined-at-the-brain would be
easier.

~~~
fastball
Yes, but logistical considerations weren't really my point.

It's debatable whether these girls are one girl or two girls, from a
personality / sense-of-self perspective.

I personally could see myself being in a relationship with someone that had a
conjoined twin. The only barriers are awkwardness and how much time I get to
spend with them if the other twin has it's own SO/social life/etc.

Conjoined at the brain is totally different. Are they two individuals? Are
they one with different personalities? Are they the same personality with two
different physical manifestations? I feel like it would just be so hard with
our culture's concept of love and self.

Does she love me? Do they love me? Does half of her hate me? It's just so
mind-numbingly complicated.

~~~
PhasmaFelis
> _It 's debatable whether these girls are one girl or two girls, from a
> personality / sense-of-self perspective._

No it's not. They have externally distinguishable personalities, and they
refer to themselves as separate people. I don't see any reason not to take
their word for it.

And even if they were one and a half people, I don't see the issue as long as
all one-and-a-half of them are into it. And if they're not, it's not as if
having conflicted feelings about someone is alien to normal human experience.
It would certainly be an odd situation, but hardly insurmountable.

~~~
fastball
Your left and right brain would probably identify as different people if your
non-dominant hemisphere could talk.

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Lambdanaut
From 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.

~~~
pvaldes
> I applaud Mother Nature for spitting on our idea of limited identity

The true mother nature's plan was probably killing the mother and both girls
at birth time. I would thank the obstetrician at charge and his/her team
instead.

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datawarrior
Flip side of that is Mother Nature also made the doctors who made it possible
for them to live. We can’t view the doctors as some outside force.

~~~
sandworm101
By that logic all technology is "natural" and there is no distinction between
the inventions of man and the creations of nature/god. Such logic sidelines
self reflection, leading to horrible places.

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MereInterest
No, it just means that self reflection must be based on something other than
an arbitrary and meaningless distinction between things that existed before
humanity and things that existed after humanity.

~~~
jnordwick
So climate change is a natural phenomenon under that interpretation?

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JoBrad
If we see ourselves as part of nature, but with a unique ability to impact
more of nature than most other forces within nature, I think we would have a
greater imperative to rectify mistakes we have made, vs seeing issues like
climate change as mostly impact “others.”

~~~
KGIII
If you ever get the chance, I recommend the book Ishmael, by Daniel Quinn.

~~~
JoBrad
Thanks - I'll check it out!

~~~
KGIII
It's a philosophical work about leavers and takers and what is the nature of
both nature and humans, as well as their role in it. It's told from the
perspective of a man taking instruction from a speaking ape.

It is something I've read many times and get something new every time I read
it. Given the context of this thread, I'm not sure I could recommend a more
salient book.

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trungdq88
Incredible. 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
That would be amazing, but unlikely, since they were described as having lower
than normal IQ. Watching the videos makes that obvious as well.

~~~
timthelion
That doesn't need to mean much. IQ tests are basically meaningless for their
complex experiences.

~~~
ShannonAlther
Meaningless insofar as that goes, but being fairly clever is necessary to
become a physician.

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vbuwivbiu
in 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_
I’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.

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cholmon
Do 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?

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marci
Makes 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)

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kensai
I 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
It 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.

~~~
teawrecks
That'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.

~~~
jacobush
Would you have thought you were two people, if the people raising you
conditioned you to think you were two people? If they had treated you as two
persons, would you (two) behave like two persons?

Also something to ponder.

And heck, as disturbing: what about two (regular) twins raised as one
person...

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hacker_9
Wow 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.

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averagewall
Why 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.

~~~
hacker_9
How are you equating breathing to be as difficult as being physically
connected to another person 24/7 exactly? Additionally because of the join
angle, you can never hold your head straight, meaning your view of the world
is constantly from a 45 angle.

The world is not designed with you in mind - you cannot drive, likely not able
to sit comfortably on an airplane, or even walk up stairs or go through single
doors without turning to the side. Try putting food in your mouth from an
angle or even having a drink. What about just sitting in a chair? And how will
you have relationships with other people? Equating all this to breathing is a
serious lacking of empathy on your part.

~~~
pdkl95
> The world is not designed with you in mind

So what. Humans can be incredibly creative. There are problems everywhere that
people overcome every day.

For a brief look into the incredible ways people adapt to disabilities, I
recommend watching this[1] Smarter Every Day video.

[1]
[https://www.youtube.com/watch?v=5CtnrK3qx_Y](https://www.youtube.com/watch?v=5CtnrK3qx_Y)

~~~
ConceptJunkie
Yeah, the world is also not designed for people with no legs, or people with
no arms, etc. Yet people with those handicaps demonstrate amazing abilities to
adapt and with the help of technology, they can overcome their limitations
even better.

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netsec_burn
WOW 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?

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yters
If two minds share the same brain, this means the brain is not the mind.

~~~
BatFastard
Its just means it can multitask

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_jal
Who 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/) ).

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timthelion
My neck hurts just looking at them. I hope they aren't in pain

