That is to say a curious phenomenon that I came across in the 1977 paper by Gazzaniga and others at reference 2. A phenomenon which was the result of splitting a mind by surgery, that is to say a young man whose two cerebral hemispheres had been in large part disconnected in order to manage down the severity and frequency of his otherwise intractable epileptic seizures. A paper which was written long after the term schizophrenia had been coined, indeed long after the term ‘split mind’ for this disorder became obsolete, but (for the avoidance of doubt) a serious disorder nonetheless, one which continues to cause much misery and worse across the world. It does not seem to respect national boundaries – for which last see, for example, reference 7.
A story which actually started for me with the much more recent reference 4. With the present post being first advertised at the end of reference 1.
The work reported at reference 2 was motivated by wanting to know more about the language dominance of the left hemisphere. The left hemisphere seems to be more involved than the right hemisphere in tasks involving language – particularly talking, hearing and reading – and if necessary can manage pretty well without the right hemisphere. While this is not true of the right hemisphere – but what can this last manage by itself? The answer seems to be everything except the talking. Another part of the answer is a suggestion that, at birth, the hemispheres are not nearly as specialised as they later become; specialisation seems to come with growth and the development of functions and faculties – although we have not yet fully answered the question of why specialise at all.
At reference 1 there was some talk of the bilateral symmetry or otherwise of the two halves of the brain. While the present authors speculated about whether the two halves of the brain might both be thought to support an instance of consciousness, with all the necessary machinery seeming to be duplicated. They conducted an experiment with the young man mentioned above, an experiment which suggested that the two hemispheres both held opinions about things and, going further, might and sometimes did hold different opinions about things. In effect, to be independent and different. A split personality indeed, not just a split brain. The authors make the point that one might well not get the same result with another such young man; their result is interesting not because it always happens, but because it can happen.
In brief, given that left field visual input mostly winds up in the contralateral, right hemisphere and that right field visual input mostly winds up in the left hemisphere, the idea was to present words and images to one hemisphere at a time. The left hemisphere could respond verbally in the ordinary way, while the right hemisphere, although unable to speak, was able to respond by the left hand (usually) spelling out the answer with the letters from a couple of Scrabble sets. This young man was unusual in that he could do this, that he had enough language in his right hemisphere.
This difference is illustrated above, with the good-bad ratings to a number of common words given by left hemisphere being very different to those given by the right hemisphere, with the right hemisphere, on this occasion, taking a reasonably consistently more negative attitude to the world: in rather a bad mood for some reason. While on another occasion reported, using different words and using a shorter rating scale, the two hemispheres gave most words the same rating.
Leaving aside the details of how exactly these experiments were done, it does not seem unreasonable to me that, in these very unusual circumstances, one hemisphere tells a different story than the other, rather as if they were both conscious entities with minds of their own.
Putting it rather loosely, in all of us, the unconscious is mulling over all kinds of stuff, considering all kinds of possibilities, generally thinking the unthinkable – and certainly the unsayable. But the normal, waking brain condenses all this muddle into a reasonably coherent short story, the story which makes it to consciousness. For example and generally speaking, during any one frame of consciousness (to take a bit of jargon from LWS-N of references 5 and 6), we only have one feeling about an object; it is either good or bad rather than both at once. While the IIT model of consciousness goes rather further and has ‘integrated’ as the first of its three title words. Consciousness is required to be integrated, to be coherent, a requirement which I believe to be mistaken. Nevertheless, in LWS-N, alternation of different feelings about things yes, coincidence, at least generally speaking, no. The LWS-N places no bar on difference, the (semi-detached) layers can accommodate difference, but the thought is that it helps, it makes one more fit to survive the struggle, if one’s conscious experience is reasonably coherent most of the time. A matter which is very much in the gift of the LWS-N compiler.
So in normal circumstances the hemispheres work together and what manifests itself in consciousness is likely to be coherent, although the story from any one person may well vary with context, with time and mood. If that working together has been grossly disrupted, as here, it is not surprising that coherence is lost.
From where I associate to Siamese twins and identical twins, which also develop independent and different personalities, while starting as they do with pretty much the same machinery, the same hardware. While the epidemic of multiple personalities which afflicted the 1970’s and 1980’s is something quite different.
We also need to remember that people with only one hemisphere, with virtually no cerebral cortex at all (very rare) and people with no cerebellum (even rarer) often seem to function more or less normally and to be conscious in much the same way as the rest of us.
With the LWS-N take on this being that its all important patch of cortex is located somewhere near the brain stem, rather than in the cortical mantle, and able to take input from anywhere in the brain. Bearing in mind that LWS-N is the final staging post on the way to consciousness: most of the heavy lifting will have been done well upstream, a lot of it in the cortical mantle, in one hemisphere or the other – or, more likely, in both.
And it may well be that a degree of bilateralism survives into LWS-N, with, in normal circumstances, both sides contributing to the final product.
I don’t know whether the present authors ever tried both hemispheres at once, getting one to say one thing and the other to spell something else - at the same time. But I do not see that success would greatly disturb LWS-N; bilateralism or layers or both could cope.
From where I associate to sometimes seeing things double, perhaps things which are too close to one, when the brain fails to merge the images from the two eyes into one. With the added complication that both the images seem to be fairly transparent. But once again, layers could cope.
References
Reference 1: http://psmv4.blogspot.com/2020/06/phrenology-redux.html.
Reference 2: A divided mind: Observations on the conscious properties of the separated hemispheres - Joseph E. Ledoux, Donald H. Wilson, Dr. Michael S. Gazzaniga – 1977.
Reference 3: Language, praxis, and the right hemisphere: Clues to some mechanisms of consciousness - M. S. Gazzaniga, J. E. LeDoux, D. H. Wilson – 1977. Something of a companion paper to reference 2. I was amused by the word ‘praxis’ which I remember from my student activist days – while not remembering (if I ever knew) what it meant – but here meaning the ability to control the movements of one’s limbs.
Reference 4: A little history goes a long way toward understanding why we study consciousness the way we do today - Joseph E. LeDoux, Matthias Michel and Hakwan Lau – 2020.
Reference 5: http://psmv3.blogspot.co.uk/2018/01/an-introduction-to-lws-n.html. A little out of date, but hopefully it will serve here.
Reference 6: https://psmv4.blogspot.com/2019/06/a-further-update-on-seeing-red.html. Inter alia, a list of the other material which has been posted. Also a little out of date.
Reference 7: Psychiatry around the globe – Julian Leff – 1981. Forty years old now, but I dare say the story still mostly stands.
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