Xref: utzoo comp.ai:8255 sci.bio:4186 sci.psychology:3905 alt.cyberpunk:5398 Path: utzoo!attcan!lsuc!xenitec!maytag!watmath!watserv1!utgpu!cs.utexas.edu!usc!julius.cs.uiuc.edu!apple!portal!cup.portal.com!mmm From: mmm@cup.portal.com (Mark Robert Thorson) Newsgroups: comp.ai,sci.bio,sci.psychology,alt.cyberpunk Subject: Re: The Bandwidth of the Brain Message-ID: <37111@cup.portal.com> Date: 20 Dec 90 18:42:05 GMT References: <37034@cup.portal.com> <1990Dec18.181935.23319@watdragon.waterloo.edu> Organization: The Portal System (TM) Lines: 175 > Beyond that, what about individuals with "photographic memories"? That would > appear to indicate a much higher bandwidth. They could memorize your 10x10 > grid in much less than an hour. I realize that these are abnormal cases, but > they show that the brain has more potential than you appear to be taking > into consideration. Excerpted from _Cybernetics_, Transactions of the Eighth Conference, March 15-16, 1951, New York. My comments at the end. ----------------------------------------------------------------------- WARREN McCULLOCH: May I abuse for a moment the privilege of the Chairman and ask two or three questions? I spent a considerable amount of time and effort during my senior year in Yale, back in 1921, attempting to evaluate how much can be recalled under hypnosis. We were by no means convinced that an infinite amount could be recalled, but only an amount which was vastly in excess of what is available in the waking state could be recalled--I would say perhaps a thousand times as much; it still has an upper limit. WALTER PITTS: Did you try simple material such as a string of nonsense syllables? McCULLOCH: We tried this sort of trick: We took master bricklayers who laid face brick and had them recall the seventh brick in the row, or something else like that, in a given year. They were able to recall any one such brick--thirty or forty items at the most. That was a brick that had been through their hands some ten years before. It is still not an infinite amount. A master bricklayer can lay only a certain number of bricks per diem even when his entire attention is riveted on laying bricks. The amount is not infinite. LEONARD SAVAGE: What would you call an infinite amount? McCULLOCH: A thousand bits per minute at the most, or something like that, that you can get back. It is not infinite. I think that is critical-- SAVAGE: Well, who could believe it could be literally infinite? And if it is not literally infinite, who could believe it would be as much as you say? McCULLOCH: There are two things here which are equally important: first, that it is vastly more than one can remember in the waking state; and, second, that it is not infinite. PITTS: You could take nonsense syllables or present a board filled with letters, and determine how many could be remembered. McCULLOCH: It is extremely difficult to get a man to attend to this, but a master bricklayer looks at the face of the brick when he is laying it. MARGARET MEAD: Did you find differences between two master bricklayers in which thousand items they would notice? McCULLOCH: No, not significantly. He mostly noticed three things-- ARTURO ROSENBLUTH: How do you go back to check? McCULLOCH: These things are verified by checking the bricks. They are master bricklayers. That means they are laying face bricks. That means that even ten years later, you can go back to that row and look at the brick. The only things you can't check are things on the opposite side of the brick or an angle off the side of the wall. GERHARDT von BONIN: How many things can the normal person remember? McCULLOCH: The estimate is that the maximum is 10 frames per second. von BONIN: No, no, I don't mean that; the normal person. McCULLOCH: On the normal person, the best man known on receiving communication in the United States Navy could give you a hundred letters in sequence at the end of having received a hundred in 10 seconds. He had to wait until he had passed through a period during which he could not recall, and then he would give you all the hundred letters. JULIAN BIGELOW: What kind of communication was it? McCULLOCH: Semaphore. PITTS: If you were to hypnotize him-- McCULLOCH: That is not more than five bits per letter. BIGELOW: But it is essentially controlled by the semaphore process. McCULLOCH: Well, this can be sent as fast as you will. It is sent by machine. DONALD McKAY: What was the redundancy in the information about the bricks? Or, to put it otherwise, how frequently did the features recalled crop up normally in bricks? McCULLOCH: In bricks, it is rather rare. The kind of things men remember are that in the lower lefthand corner, about an inch up and two inches over, is a purple stone, which doesn't occur in any other brick that they laid in that whole wall, or things of that sort. The pebble may be about a millimeter in diameter. BIGELOW: How could he possibly remember thirty of those features on this one brick? McCULLOCH: Oh, they do. It is amazing, when you get a man to recall a given brick, the amount of detail he can remember about that one brick. That is the thing that is amazing. I note, as a result, that there is an enormous amount that goes into us that never comes through. LAWRENCE KUBIE: This is comparable to the experiments under hypnosis, in which the subject is induced to return to earlier age periods in his life. McCULLOCH: I have never done any of those. KUBIE: In these you say to the subject, "Tell me about your seventh birthday," or his ninth birthday, or something of that kind; and he gives you verifiable data about the party, who was there, and so on. McCULLOCH: I have seen my mother's uncle, who was an incredible person in the way he could recall things--he was law librarian in Washington for a few years--testify that he had looked at such and such a document some twenty years before, and shut his eyes and read the document and the signatures under it. SAVAGE: I don't have absolute recall, but I can remember hearing that story more than once in sessions of this group. McCULLOCH: They said, "But the document does not read that way; it read so and so from there on," and he replied, "Then the document has been altered and you had better check the ink." And when they checked it, it was a forgery. SAVAGE: It's the same story, all right. ----------------------------------------------------------------------- I think McCulloch has described two phenomena here. In the first place, we have the bricklayers who remember bricks because they study them thoroughly in order to make decisions about which side faces front, and which bricks go where. For example, if the bricks you're using to build a wall come from two different batches -- one with purple stones and one without -- it would be your responsi- bility as a master bricklayer to distribute them in an aesthetic pattern. You would not simply place them in the order they came, with part of the wall having purple stones and part not. So it is no surprise that this information -- having filtered through the highly refined judgement of the master bricklayer -- would have a persistence in an old layer of memory. I would not be surprised if a master programmer could be made to recall each line of code he has written, under hypnosis. This is not at all the same thing as having a photographic memory of the face of each brick. The bricklayer is remembering details he used to make his decisions, so he is remembering the bricks at the resolution at which for example a master chessplayer would remember a chess position, rather than the detail of an actual mental photograph (if such a thing could exist). The other phenomenon described by McCulloch is the more well-known example of a person who claims to have photographic memory. I believe this is nothing more than a person who has developed a mental exercise which happens to be useful for providing memory cues. He might even believe that he is viewing the actual image of the document in his mind, but it is really nothing more than an internally-generated synthetic image of what he believes the document looks like--in the same manner that people who develop an ability to manipulate their brain's sense of location often claim to "astral travel" (i.e. the "soul" leaves the body and goes floating around the room, house, outdoors, etc.).