How researchers discovered we have “two brains” [video]
bbc.com
bbc.com
... rather, the left-hemi-visual-field from both left- and right-eyes goes to the right brain, and the right-hemi-visual-field from both eyes goes to the left brain, as depicted in [1].
[1] http://fourier.eng.hmc.edu/e180/lectures/eye/node4.html
EDIT: grammar
Central vision is preserved though, because the fovea projects to both hemispheres.
In my case the aura of my migraines (that I thankfully only had during puberty) were limited to the left hemi-field. Which I guess suggests that the migraine was "centered" in the right brain hemisphere.
It is possible to trigger the phenomenon by hurting the brain (e.g. sprinkle acid on a rat's brain, WP has a neat video: https://en.wikipedia.org/wiki/Cortical_spreading_depression) so we suppose that it is a defense mechanism in humans too, but we're not sure what causes them.
I've done research on migraine, 10 years ago, but I haven't kept up with the field. There are hypotheses, but no known cause for the headaches and associated symptoms.
"The Man Who Mistook His Wife For a Hat" is another classic.
https://en.wikipedia.org/wiki/Theory_of_multiple_intelligenc...
to which I subscribe, in a form.
The parent video is about the idea that an "individual" human mind can be described as being composed of subordinate minds. In this case, left-side vs. right-side.
The Wikipedia article is about the idea that there's no single metric by which we can judge human intelligence. This is, it's theoretically impossible to have any score, like IQ, that cleanly qualifies how smart people are relative to one another.
[1] https://en.wikipedia.org/wiki/Bicameralism_(psychology)#Issu...
It has the disadvantage that it is non-verbal and does not work quickly, on command or under pressure. You need to give it time to work and you need a quiet, non-focused environment for it to bubble up it's conclusions. Basically, you need to study as much as you can, then go for quiet walks where you relax and don't think about the problem.
It also has the disadvantage that, because your foreground process did not do the work to understand the problem (it just got a cliff notes answer), if the problem changes, your foreground process won't be in a good position to re-integrate the knowledge it didn't work through in order to deal with the changed problem.
The act of explaining a problem verbally to someone else forces you to be explicit about details that you gloss over when you think about the problem internally. The fun part is that you don't actually need a real person to explain to. Just going through the motions and explaining out loud to no one (or to a toy) is nearly as effective.
- explains "prayer": talk it over with your God, leave it in God's hands, you get an answer.
- may have gteater survival value than the chatter we think of as "consciousness", and may be the actual intelligence that we're famous for.
> In 2007, they announced a startling discovery. Stevens was trying to identify the proteins that recognized and eliminated neuronal synapses during visual development. “The strangest finding was that a protein that usually tags and removes pieces of dead cells, bacterial remnants, or cellular debris was also being reworked to tag and remove the synapses,” she said. Mice designed to lack tagging proteins—called complement proteins—had problems both in clearing cellular debris and in tagging and pruning their synapses.
> The Stevens and Barres study, published in the journal Cell in 2007, documented one of the most arresting instances of repurposing in biology: a protein designed to ticket germs and junk for destruction had been co-opted by the nervous system to ticket synapses for destruction. “It reinforces an old intuition,” my psychiatrist friend Hans, in Boston, told me. “The secret of learning is the systematic elimination of excess. We grow, mostly, by dying.”
https://www.newyorker.com/magazine/2016/03/28/the-genetics-o...
How presumptive. Speak for yourself.
Our brain is composed of neurons. Different subsets seem to have more or less specialised functions. Any subset can be seen as it own 'thinker'. We think of them as larger units based mostly on the amount of communication / how independently they can function.
Sometimes it is helpful to think of our mind as been made of many smaller 'thinkers'. Though there is no crisp boundary, every neuron is its own individual, at one extreme.
And I think it is sensible to speak of groupthink as a mind, with thinkers contributed by lots of people. So at the other extreme all is one super mind.
I think it can be useful to think of 'god' that way (as in the will of god, the desires of god, the thoughts of god), as much as a corporation, a culture, a nation. Though I admit you have to take care not to get carried away with the implications and end up mired in sloppy reasoning.
It is also not surprising that, because axon connections are many orders of magnitude more efficient than language, the most useful grouping is at the level of an individual.
That does not sound useful in the slightest.
Socialisation and attendant technologies suggest otherwise: there's plenty of 'me' which is opaque to me, of me that precedes me, of me that derived from other minds. 'I' may even reside briefly in other minds, such as (trivially) in the form of this comment.
The more we look at how individuals are structured from somatic to social levels, the less convincing the notion of individuality becomes.
I definitely agree with your last sentence. And this can be as simple as the idea, often observed, that someone 'lives on' in the minds of their loved ones after death. For me that is entirely non supernatural or mystical. As you say (and nicely phrased) our identity is a function of everything from the somatic to the social level.
True, although consciousness itself is rather poorly defined. There are also other related issues like qualia. But I'm not sure it needs to 'account' for those things. To observe that there are certain mental phenomena that are evident at different scales.
> A mind, at the very least a moment of experience, is a coherent whole.
That rather assumes your conclusion. In the example of a divided brain, a stimuli may be presented to only half the brain. How would one know whether one's experience of 'coherent whole'ness was accurate?
> Thinking of neurons as entirely discrete units makes the binding problem insoluble.
No more than thinking of base pairs in your DNA as discrete units makes higher order phylogenesis insoluble. To recognise that discrete units are simple does not mean that large aggregates of them cannot display fundamentally different dynamics.
Fun fact: He wrote the book over a period of 20 years.
Recalling distant memories asynchronously after struggling to remember anything about it sometimes feels very much like another person interrupting and delivering the information once it's found.
1. It's state dependent.
Example: I had a tortured first pregnancy and the birth was awful. For years, I couldn't clearly remember it.
Then I had a lengthy medical crisis that involved constant, excruciating pain. Suddenly, I could clearly remember the birth of my first child.
2. It's context dependent.
For example, people frequently fail to identify individuals they know if they run into them someplace they wouldn't expect to see them. They may realize they know the person, but just can't place them. (I have experienced this.)
This is also the mechanism behind going to do a thing, forgetting what it is, remembering when you return to where you were.
3. Emotion is a form of memory.
People with strong affect can make snap decisions based on "gut feeling." People with low affect cannot make snap decisions. They lack the file that sums up all their pertinent experiences as either "I have good feeling about this" or "I have a bad feeling about this."
4. "Muscle memory"
Some people think better while active. This is your stereotypical Pacer.
If you keep a dream journal, it's easier to remember dreams if you keep a pen and notebook on the nightstand and make notes without getting up at all. It's best to stay in bed and try to not leave your sleep position. Dreams can sometimes be retrieved by returning to whatever position you were laying in while dreaming.
5. Some people think in pictures. Some in words. This effects memory storage.
For most people, conscious recall of memory corresponds to learning to speak. It apparently heels people catalog their memories so the files are accessible.
I have a son who thinks in pictures. At some point, it became clear he could access pre-verbal memories, but it was like listening to someone translate a thing into English.
We actually went through a period where he waited until everyone else was asleep, then he would share his memories with me. Translating them to words from pictures helped him more readily access them.
There's no doubt tons more stuff to know about memory. This is very off the cuff.
This feels like people playing with words to grab attention.
So, the left hand's failure to pantomime screwdriver use probably reflects the commissurotomy patient's right hemisphere's inability to access her left hemisphere's knowledge of tools. (That this only happens when eyes are closed probably means the right hemisphere just observed and copied the right hand's behavior when eyes were open.)
Had a fun chat with someone interested in this at a bar a few weeks ago who offered a theory that the best pro basketball players are right hand/right eye dominant or left hand/left eye dominant, and that anybody with mixed dominance just can't cut it. Apparently the military just wont take you as a pilot or sniper if you have mixed hand/eye dominance?
Calling it now: laterality is central to who we are, and is currently underappreciated—especially in AI research (though I'd be delighted to hear from AI folks who disagree!).
EDIT: lots