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When You Split the Brain, Do You Split the Person? (aeon.co)
An anonymous reader shares an article: The brain is perhaps the most complex machine in the Universe. It consists of two cerebral hemispheres, each with many different modules. Fortunately, all these separate parts are not autonomous agents. They are highly interconnected, all working in harmony to create one unique being: you. But what would happen if we destroyed this harmony? What if some modules start operating independently from the rest? Interestingly, this is not just a thought experiment; for some people, it is reality. In so-called 'split-brain' patients, the corpus callosum -- the highway for communication between the left and the right cerebral hemispheres -- is surgically severed to halt otherwise intractable epilepsy. [...] What, then, happens to the person? If the parts are no longer synchronised, does the brain still produce one person? The neuroscientists Roger Sperry and Michael Gazzaniga set out to investigate this issue in the 1960s and '70s, and found astonishing data suggesting that when you split the brain, you split the person as well. Sperry won the Nobel prize in medicine for his split-brain work in 1981. [...] Case closed? Not to me. [...] To try to get to the bottom of things, my team at the University of Amsterdam re-visited this fundamental issue by testing two split-brain patients, evaluating whether they could respond accurately to objects in the left visual field (perceived by the right brain) while also responding verbally or with the right hand (controlled by the left brain). Astonishingly, in these two patients, we found something completely different than Sperry and Gazzaniga before us. Both patients showed full awareness of presence and location of stimuli throughout the entire visual field -- right and left, both.
The brain is perhaps the most complex machine in the Universe
That reminds me of an Emo Philips joke: I used to think the brain was the most amazing thing in the universe. Then I remembered what was telling me that.
"The brain is perhaps the most complex machine in the Universe"
Seriously who writes junk like this? How much of the universe have they actually experienced? It's absurd.
...no with a BUT
If you like this kind of stuff, read Phantoms in the Brain: Probing the Mysteries of the Human Mind by V. S. Ramachandran. Good book.
If a person has Dissociative Identity Disorder (Multiple Personality Disorder) we still see him as one person. Cutting a brain in half does not make a difference.
There have been people where they lost half their brain. They do not become half a person. They are just the same person with, in some cases, a complete different mentality.
So: leave it in the body, two people. Put it in two bodies: one person.
If they are born with two brains and one body, it will be seen as two persons.
These are pretty clear situations that already exist.
I feel as if the person is looking for a solution to a problem that does not exist.
Don't fight for your country, if your country does not fight for you.
You've got to be very careful of poisoned samples in cases like these. If the person in the experiment has any way of telling beforehand what's happening, or gaining context in some other way, then you're not really reading what you think.
This reminds me of the work of folks like James Randi, who would go to scientists with simple magicians tricks - like 'levitating' a matchbook by fixing it to the skin on his hand, or other crude indirect tricks, and since the answer wasn't immediately obvious, many 'researchers' would happily jump to the conclusion that he was psychic or something similarly absurd - because they really wanted to believe it. He was just nice enough to quickly disabuse them of this by showing them the trick with a friendly admonishment. There's a lot of hucksters who don't do that.
People fool themselves - and you have to design experiments to account for that.
That said - I can empathize with the desire of folks putting together flawed experiments. Journals just eat up non-obviously flawed 'revolutionary' results and you can make a lot out of a 'simple mistake' - whether you mean to or not.
...you kill the person. All other questions in this thought experiment are irrelevant and probably useless.
We'll make great pets
I don't know much about the brain but I do know if you split peas you make soup.
"That's the way to do it" - Punch
Brain is more like multi-core CPU with dedicated special-purpose cores. When you split, as research shows us, you still can communicate with "talking persona" and "non-talking persona". So yes, effectively there are two "people", but they always been there. They just no longer coordinate well.
I find it difficult to believe that two COMPLETELY SEPARATE subsystems (left brand with right eye vs. right brain with left eye) somehow "magically" communicate. I suspect that either the corpus callosum is not completely severed or they did not completely separate the visual fields so that both eyes could actually see the item in question.
This really smells of unmentioned test issues which would be explained by religious bias. The last part of the article sounds like someone wants to put magic back in the description. :(
That the brain is approximately like jello in texture. That being said it also has some plasticity - it probably re-grew the connection to some level. It happens.
Earlier experiments used a partition to separate the left and right visual fields. One experiment I recall reading about was done like this: On one side of the partition they would place an implement, such as a fork. They would then have the subject pick up the implement in one hand and ask them to identify it, and do various things with it. The results were markedly different depending on which side of the partition, and therefore which eye and which hand, were engaged.
Here is some general information on the early experiments.
I've fallen off your lawn, and I can't get up.
While not as rapid nor efficient, the body's nervous system still connects the two halves of a split brain. It's a slower rural road type of path, that is not as efficient as the expressway connection that was cut. But, it exists and explains why the two halves still communicate, albeit less efficiently.
CGP Grey did a nice, insightful piece on this in a 5 minute youtube piece discussing just this thing. I like his videos in general ...
Even a properly function Corpus Colusum is at best a "low bandwidth" connection. So even in a fully normal brain, the two hemispheres run "semi-antonymous", but share information. So this "decoupled" operation is already built into every brain. When the link is severed the brain looks for other means of syncing up. In some cases since both halves get the same (or at least really similar) input, they both process the info and achieve consistent results. Only when something "odd" happens, like the experiment, that feed the two hemispheres drastically different data does a difference appear. However this sort of drastically differing data confuses a normal brain too, just less so.
Splitting the brain actually happens.
Szhizophrenia
Your hypothesis does not directly explain why results differed so dramatically between patients.
Brain plasticity is a simpler and much more likely answer. When a neural research paper starts from an assumption that the left visual field is processed by the right side of the brain for everybody then I *know* the research will not provide generalizable conclusions. Brain plasticity and normal development is going to lead to some people who use the left side of the brain to process the left visual field and even some people who use both sides of the brain to process both visual fields.
Nor do patients who have had one hemisphere completely removed (not just disconnected) end up half blind.
It would take too long to detail why, but the hypothesis these researchers want to test simply cannot be ethically tested on a sufficiently large population to answer their question.
No wonder tech people are so neurotic -trying to think themselves into existence.
A self, an individual, is an existing subject. A thought about something does not mean it exists.
E.g. I can think about unicorns all day, but that doesn't mean unicorns exist.
I think this is exactly a thought experiment.
neural interconnects are much more prevalently cross-hemisphere in women (vs within-lobe for men). ...
see for example, the Gur's studies at UPenn, Shah's work at Columbia, Halpern at Claremont, Cahill at Irvine, etc etc etc
I lived across the street from a young girl - I'll call her 'Sandra' - who had grown into her mid-to-late teens when I moved away. She had been born without a corpus callosum, and her parents were warned that she would never be anything approaching normal, and might not even live.
Apparently her parents did something right, or she herself possessed some kind of will or magic that got her beyond the difficulty. Other people who had kids born with the same lack would ask Sandra's parents for advice and support. Sandra was always a bit quirky, and when she was younger I always had the sense that she wasn't quite normal, even before I knew her history. But she was sweet and funny, she made pretty much normal progress in school, and she grew into a lovely young woman who didn't wasn't out of place among her peers in any significant way.
So I'm not surprised at these new findings. The human brain seems to be very good at routing around damage in ways that we don't yet understand.
'The Economy' is a giant Ponzi scheme whose most pitiable suckers are the youngest among us and the yet-unborn.
Yes
blew. my. mind. ;)
I remember seeing studies about this stuff when I was a kid.. Still creeps me out.
Did anyone else think of Substance-D from A Scanner Darkly when they saw this?
The first thing I thought of was 3 people sitting in a room trying to figure out how and 18-speed bike only has 9 gears.
FTH (and FTA):
"Fortunately, all these separate parts are not autonomous agents. They are highly interconnected, all working in harmony to create one unique being: you."
Almost none of that is true: You aren't unique. You aren't particularly highly interconnected. You aren't in self-harmony. You aren't a single "being". In fact, there are more bacterial cells in "you" human cells in "you"...and many peer-reviewed papers confirm that those bacteria do contribute to determining "your" behavior. And those autonomous agents inside of you? They are pretty darned autonomous.
My freshman psych professor explained it to us this way: "There are a whole lot of different behaviors we can observe. Different parts of the organism have different jobs. One of those jobs is to make up stories. We call that one consciousness. The illusion that each healthy uninjured human body has one integrated consciousness is a complete fantasy. Injuries and other pathologies expose this fact in interesting ways, but fragmented and incomplete consciousness is the normal way of being for all of us."
A good way to see the separation is to compare desire vs behavior. If there was one fully integrated and aware "consciousness", then desire and behavior would always be consistent. They're not. Not even close.
Consider things we do even though we'd prefer not to: Habits, compulsions, and addictions. Tobacco smoking could be any of those. It's not hard to find a smoker who will tell you "I want to stop smoking".
Or neurological phenomena, for example "the yips" (google it, it's a golf thing).
On a more positive note, consider practiced skills--like touch-typing, playing musical instruments, batting a baseball, rollerblading, etc. You can't consciously decide "I will skillfully perform this act" and *poof* it's done.
There's something in you that does (or does not) those things. But it's not the thing that's speaking to the person next to you.
Lovecraft put it quite nicely:
“The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents. We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far.”
"Reality is that which, when you stop believing in it, doesn't go away." - Philip K. Dick
Don't split just brains. Split people. Splitter splatter axe slasher.
Are twins the same person? Can science prove the soul exists? Can... Whoa I just passed out from metaphysical stupidity
The guy with a tiny brain shows that we don't know a lot about the mind/body connection. That this guy was able to function as a normal human being is really astonishing.
Most interesting questions are not defined precisely enough to have exact answers. The answer is fuzzy. In this example, the word "person" doesn't have a precise meaning, but just some vague context-sensitive meaning which we mostly agree on based on our shared upbringing. In some cases, some authority will make a more precise but arbitrary definition for the purposes of law. For example, legally blind. Legal person. So, if you split the brain, do you split the person? It depends on if some authoritative body declares it to be so.
Our brains are as large as they are so we can lie, cheat and persuade other humans and so we can throw things. If I want throw a rock and hit something it requires a degree of precision and coordination between my muscles that normally can't be done with nerve cells. The way our nerves work creates to much jitter. To solve this, we have orders of magnitude more nerves controlling our muscles than other mammals, so that the average transmission speed of signals in our nerves much more constant and predictable.
Playing chess, doing calculus or memorizing Pi to 100 digits has no advantage on the plains of Africa. But lying to a woman so I can sleep with is a really good advantage. Although for a woman, being able to figure out if I'm lying or being able to lie to me might be useful. So we get into a mental chess match each trying to outsmart the other and the winner is the one who thinks the most moves ahead.
The net result is we have a lot of excess brain capacity and excess communication pathways for doing almost everything.
The corpus callosum is not the only connection between the halves of the cerebral cortex. There are all of the lower brain structures. And most modern callosotomies are incomplete. So no surprise that a modern researcher would get different results than the past.
Bruce Perens.
This press release from January the year. Same university. Not to say that it isn't interesting research, it is, but it is not news.
When all you have is a hammer, every problem starts to look like a thumb.
As far as I can say Cerebellum is never split ( https://en.wikipedia.org/wiki/... ). When a brain is "split" they cut the Corpus callosum ( https://en.wikipedia.org/wiki/...). The cerebellum may offer enought connections between the two emispheres
They split one brain structure, not the whole neurological system. I don't think they even split the whole brain, so it could be that lower level brain structures are picking up the slack. At the very least we know they didn't split the spine since that'd kill you. It's conceivable that these lower levels of the brain and peripheral nerves are an integral part of being a person. I've heard that the heart actually turns out to have more to do with personality than modern medicine once thought. It's not just a stupid pump. Users of artificial hearts report that it lacks that certain something. Receivers of transplanted organs sometimes acquire traits from the donor, such as food preferences. You wouldn't think such traits could be conferred via those organs. Your sense of self may be more "distributed" than some of us think.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
The author's entire premise is build on when you sever the corpus callosum, the two hemispheres are no longer communicating. He doesn't review the scientific evidence to assume this, yet he is amazed when this does not seem to be the case. I'm not impressed. Neither am I (somehow typed with only my left hand when my left eye wasn't watching).
What could go wrong?
After splitting the brain the person is dead.
Speaking as someone who does have a division......one learns to communicate across the divide, both internally and externally through little cues. Yes, different parts of me are separate but there is a lot of team work going on. Growing up I thought this was normal, then I found out that most other people, everyone I checked, operated totally differently. Bizarre.