Well, here is the great Carl Sagan explaining the evolution of the brain in a bit more detail, and with his quintessential optimism.
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Carl Sagan on the Human Brain
I recently posted an awesome entry about the evolution of moral judgments (here), and how these seem to be directly related to the evolution of the brain, from the utterly guttural and visceral to the more calculating and representational character of abstract thought.
Well, here is the great Carl Sagan explaining the evolution of the brain in a bit more detail, and with his quintessential optimism.
.
Well, here is the great Carl Sagan explaining the evolution of the brain in a bit more detail, and with his quintessential optimism.
.
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Confession: I haven't actually watched this video yet. Not because I'm not interested, but because I'm at work and I haven't had enough time to come up with some creative reason as to why I'm fiddling around on the internet watching videos that appear to be completely unrelated to my tasks at work. I'm sure if i had a bit more time I could somehow relate the evolution of the brain to my current job, but not right now. Anyway, this post, along with the current book i'm reading, has got me thinking about the human brain and unconsciousness, and even more so about the brain and dreaming. I would like to pose a few questions:
ReplyDelete1. From experience I know that you can "see" your dreams, and you can even see colors in your dreams - you can make distintions between red and yellow and blue and white - how is this possible when your eyes are closed? Isn't it true that images are formed in your brain (put simply) by the firing of neurons which are triggered by light hitting your eyes? Is it possible for these neurons to fire without any stimuli?
2. Is it possible for people who are born blind to dream, or have visual dreams?
3. Can you also hear and touch things (maybe feel the pain from a scraped knee) in your dreams?
4. Has anyone ever been hypnotized? From what I understand, you are still aware of what is going on around you. Or is this not the case? You are not unconscious though, so what state of mind are you in when you are hypnotized?
I know this is a bit off the topic from what the blog was really focusing on, but the evolution of the brain has led to many "side effects" (or affects?) which, to me, seem quite fascinating to contemplate. Anyway, just a little food for thought I hope.
That is an awesome comment! So glad to get nice interesting responses like that... Anyway, here is my attempt to answer what I can:
ReplyDelete1. The way dreams seem to work is the following: during wakefulness your sensory apparatus is bombarded with perceptual stimuli, which are converted by your brain into electrochemical signals and memory bits (not sure whether these are continuous or discrete). This is an important point: visual stimuli gets converted to a different kind of information in the brain, and ceases to be visual if by visual you mean somehow directly related to the effect of light on your eyes. When you are dreaming you experience a bunch of these converted memory bits, even though there is no longer any (or most) of that direct sensory experience by the sense organs. The point is that once the information is in the brain it acquires its own neurological language and storage form. So dreams are your brain making all kinds of associations between many different random memories fired by your neurons, but the whole process is not just random: your brain tries to "make sense" of all this seemingly discombobulated data by creating a more coherent narrative. This is why when your body feels the wetness from you unintentional peeing in bed you have a dream about swimming or about rain or about waterfalls. If you hear thunder during a rainy night your dream might take that noise and turn it into you hearing someone get shot, or something like that.
2. Great question! The philosopher David Hume was one of the first people to contemplate this idea. As an empiricist he was arguing against the rationalists that knowledge of the world doesn't come from reason, as they thought, but from perception. One of his most devastating arguments against the rationalists was that without the proper sense organ it is actually impossible to have any corresponding ideas. In other words, if you are born blind you could not possibly have any idea of what color is. This is easy to confirm, and was partly the motivation by a very influential paper by philosopher Thomas Nagel, entitled "What is it like to be a bat?" The general point is that it is impossible for us to create a "visual" picture of the world based on sound the way certain animals, like bats and dolphins, do. So, the short answer is no. You can also confirm this in a very easy way: try explaining to someone who was born blind what color is... it's going to hurt your coconut...
Now, if you were not born blind but became blind later on in life, then yes, your dreams could contain visual content.
3. I don't see why not. If the data is in your brain (from memory), then this should be possible. Whether the intensity of the experience is as vivid as actually directly experiencing the pain might be a different question. Hume would say it could never be as vivid, and he's probably right, but I don't actually know for sure.
4. That's such a good question I honestly have no idea... sorry..
Thanks for the comment!!!
I just found an article based on a study of the dreams of blind people, and part of the finding says "those blind since birth or very early childhood had (1) no visual imagery and (2) a very high percentage of gustatory, olfactory, and tactual sensory references."
ReplyDeleteYou can find the entire paper here: http://psych.ucsc.edu/dreams/Library/hurovitz_1999a.html
I've been thinking about the hypnosis question and then it hit me: most people are hypnotized on an everyday basis: religion!!!!
What is hypnosis: intense suggestibility, to do or believe just about anything.
And I'm not just trying to be mean here. I imagine that suggestibility has great evolutionary value, for cognitive learning capacity and group cohesion at least...
What do you think?