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Split Brain Does Not Lead to Split Consciousness

neurosciencenews.com

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Re: Split Brain Does Not Lead to Split Consciousness

#81

Post by jdpigeon »

joeyo wrote: post #17
advisedwang wrote: post #2

Interestingly this work contradicts not just previous theory, but also previous experimental result. I would be interested to see if they have a critique for why the previous runs of the experiment provided a different experimental result.

They discuss a few possibilities. The first is cross-cueing, which they describe as " ... behavioural tricks, such as touching the left hand with the right hand" [1]. However, they also discuss a number of reasons why they think cross-cueing did not play a role. The second (and imho quite interesting) explanation is that the split-brain phenomenon could be transient: their subjects have had between 10 and 20 years to…

That was where my mind went as well. We can't ignore the incredible feats of neuroplasticity that undoubtedly happen in a split brain patient over a decade.That would make an interesting body of work in and of itself.

Re: Split Brain Does Not Lead to Split Consciousness

#82

Post by jdpigeon »

joeyo wrote: post #17
advisedwang wrote: post #2

Interestingly this work contradicts not just previous theory, but also previous experimental result. I would be interested to see if they have a critique for why the previous runs of the experiment provided a different experimental result.

They discuss a few possibilities. The first is cross-cueing, which they describe as " ... behavioural tricks, such as touching the left hand with the right hand" [1]. However, they also discuss a number of reasons why they think cross-cueing did not play a role. The second (and imho quite interesting) explanation is that the split-brain phenomenon could be transient: their subjects have had between 10 and 20 years to…

That was where my mind went as well. We can't ignore the incredible featss of neuroplasticity that undoubtedly happen in a split brain patient over a decade.That would make an interesting body of work in and of itself.

Re: Split Brain Does Not Lead to Split Consciousness

#83

Post by waltwalther »

YeGoblynQueenne wrote: post #38
insickness wrote: post #33

A few years before he died, I heard Kim Peek speak at an event. He was a savant who retained 98% of everything he read. He would memorize phone books simply by reading them once. When he read, his left eye would read the left page while his right eye would read the right page at the same time. He could tell anyone the sports scores listed in the newspaper on the day they were born. He was also severely socially impai…

My problem with that sort of demonstration of amazing memory powers is that I have no way to check the sports scores on the day I was born as quickly as the person who says they're retrieving them from memory does so. Even if I could just google them (there might be some online sports results archive or something- it would still not mean much unless I could find an identical copy of the exact listing the mnemonist me…

Reddit troll thread detected.

Re: Split Brain Does Not Lead to Split Consciousness

#84

Post by phkahler »

Sniffnoy wrote: post #32

This is an interesting experiment, and it may show that "split consciousness" is a mistake, but I don't think "unified consciousness" is the correct conclusion from that. I'd say instead that more likely this is just an edge case where the "consciousness" abstraction breaks down; it's an idea based on people who haven't had their corpus callosum severed, there's not necessarily any reason to expect that it continues…

From TFA: According to Pinto, the results present clear evidence for unity of consciousness in split-brain patients.

I only read it as unified awareness, not consciousness. I recall reading that some split people were asked questions about their aspirations and got different answers depending which side of the brain they asked (you can ask by restricting input to half the visual field, or one ear or whatever, the response can be in writing). Having different goals in life seems more like consciousness than being aware of the location of some stimulus.

Re: Split Brain Does Not Lead to Split Consciousness

#85

Post by phkahler »

nicklovescode wrote: post #4

My knowledge of neurobiology is weak. Having received a full callosotomy, how are the hemispheres able to communicate even at 1 bit / s? Secondly, how is that estimate generated?

That 1 bit per second made me laugh. The author is clearly trying to make a name for himself. Awareness of the location of something is extremely far removed from consciousness. I wouldn't put much weight on this one.

Re: Split Brain Does Not Lead to Split Consciousness

#86

Post by Zigurd »

joeyo wrote: post #17
advisedwang wrote: post #2

Interestingly this work contradicts not just previous theory, but also previous experimental result. I would be interested to see if they have a critique for why the previous runs of the experiment provided a different experimental result.

They discuss a few possibilities. The first is cross-cueing, which they describe as " ... behavioural tricks, such as touching the left hand with the right hand" [1]. However, they also discuss a number of reasons why they think cross-cueing did not play a role. The second (and imho quite interesting) explanation is that the split-brain phenomenon could be transient: their subjects have had between 10 and 20 years to…

That's what leapt out at me. These brains have had years and maybe decades to learn to reunify themselves. Split brain experiments have always shown a strong drive for presenting a unified personality even as the experiments showed a non-unified experience and response.

So even if neuroplasticity in the cranium can be ruled out, the "bandwidth" and subtlety of cross-cueing, or some unknown means of communication, might have grown.

Re: Split Brain Does Not Lead to Split Consciousness

#87

Post by todd8 »

nicklovescode wrote: post #4

My knowledge of neurobiology is weak. Having received a full callosotomy, how are the hemispheres able to communicate even at 1 bit / s? Secondly, how is that estimate generated?

The August, 1967 article in Scientific American on the split brain has an interesting comment about communication between the two parts of the brain: if one side of the brain saw a drawing (by showing the picture to only one eye), the person might not be able to describe it because voice functions were handled on the other side of the brain, but if the drawing was somehow embarrassing the facial flushing (from seeing a sexy picture on one side of the brain) could be detected by the voice side and the subject would be able to vocalize that he or she was seeing a racy picture.

Note that my recollection of this 1967 article on the split brain is a bit sketchy, I read this article in a library (in 1967) and it is unfortunately now available only for purchase on the Scientific American website.

Re: Split Brain Does Not Lead to Split Consciousness

#88

Post by lazyant »

todd8 wrote: post #87
nicklovescode wrote: post #4

My knowledge of neurobiology is weak. Having received a full callosotomy, how are the hemispheres able to communicate even at 1 bit / s? Secondly, how is that estimate generated?

The August, 1967 article in Scientific American on the split brain has an interesting comment about communication between the two parts of the brain: if one side of the brain saw a drawing (by showing the picture to only one eye), the person might not be able to describe it because voice functions were handled on the other side of the brain, but if the drawing was somehow embarrassing the facial flushing (from seeing…

yes, this was described in Roger Penrose's The Emperor's New Mind; different pictures shown to the left or right eye and getting different answers

Re: Split Brain Does Not Lead to Split Consciousness

#89

Post by c3534l »

YeGoblynQueenne wrote: post #73
c3534l wrote: post #51

Earlier quoted context omitted.

Kim Peek was an extremely well documented individual. That he retained seemingly inhuman amounts of information is not under dispute, even though such charlatans do exist.

The problem is that I'm well aware that charlatans do exist [1] but I've no idea why you say that his skils are not under dispute. Does this mean you know of some sort of test, some demonstration in controlled conditions etc? I'd like to see it, too, please. Edit: How was he well-documented? Where is that documentation? ___________________ [1] See (or rather, avoid seeing) here: http://www.dailymail.co.uk/news/articl…

Because you can put him in a room alone and ask him questions. Many, many people have interviewed and investigated him. He was also severely disabled mentally, he's not a normal guy who is really smart. He was a mentally retarded person who could not care for himself. There was a documentary in which he spoke to neurologist VS Ramachandran and they showed how he was unable to grasp the concept of a metaphor, taking idioms of speech literally. I don't think he was capable of magic tricks. This is also well beyond small areas of knowledge. The guy was a walking wikipedia. His FMRI also showed an extreme malformation of the brain. He was completely missing the corpus callosum and several other very important structures. https://cdn.psychologytoday.com/sites/default/files/blogs/11... It's pretty damned hard to fake an FMRI like that. Essentially Kim Peek was not filtering any information that got into his head. It was all equally important and it's questionable how much he really understood the things he memorized (which he did hours and hours and hours of each day).
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