PGOETZ@LOYVAX.BITNET (09/15/88)
Date: Fri, 9 Sep 88 10:12 EDT From: PGOETZ%LOYVAX.BITNET@MITVMA.MIT.EDU Subject: I got rhythm To: AILIST@AI.AI.MIT.EDU X-Original-To: AILIST@AI.AI.MIT.EDU, PGOETZ Here's a question for anybody: Why do we have rhythm? Picture yourself tapping your foot to the tune of the latest Top 40 trash hit. While you do this, your brain is busy processing sensory inputs, controlling the muscles in your foot, and thinking about whatever you think about when you listen to Top 40 music. If you could write a conventional program to do all those things, each task would take a different amount of time. It would "consciously" perceive time at varying rates, since a lot of time spent processing one task would give it less time of "consciousness" (whatever that is.) So if this program were solving a system of 100 equations and 100 unknowns while tapping its simulated foot, the foot taps would be at a slower rate than if it were doing nothing else at all. I suspect that the same would hold true of parallel programs and expert- system paradigms. For neural networks, an individual task would take the same amount of time regardless of data, but some things require more subtasks. It comes down to this: Different actions require different processing overhead. So why, no matter what we do, do we perceive time as a constant? Why do we, in fact, have rhythm? Do we have an internal clock, or a "main loop" which takes a constant time to run? Or do we have an inadequate view of consciousness when we see it as a program? Phil Goetz PGOETZ@LOYVAX.bitnet
bnevin@CCH.BBN.COM (Bruce E. Nevin) (09/19/88)
Date: Thu, 15 Sep 88 09:01 EDT From: Bruce E. Nevin <bnevin@cch.bbn.com> Subject: Re: I got rhythm To: pgoetz%loyvax.bitnet@mitvma.mit.edu, ailist@ai.ai.mit.edu cc: bn@cch.bbn.com Subject: Re: I got rhythm In AIList Digest for Thursday, 15 Sep 1988 (Volume 8 : Issue 83), we read the following from Phil Goetz (PGOETZ%LOYVAX.BITNET@MITVMA.MIT.EDU): PG> Here's a question for anybody: Why do we have rhythm? | | Picture yourself tapping your foot to the tune of the latest Top 40 | trash hit. . . . Different actions require different processing | overhead. So why, no matter what we do, do we perceive time as a | constant? Why do we, in fact, have rhythm? Do we have an internal | clock, or a "main loop" which takes a constant time to run? Or do we | have an inadequate view of consciousness when we see it as a program? The music has rhythm. The foot tapper has synchrony. There are lots of physiological processes that are rhythmical in nature, and with which one can synchronize other behavior. Some are ongoing, notably heartbeat, breathing, and brain waves. Others are easier to start and stop, like walking or running. However it's done, it seems straightforward for organisms to set up an ad hoc oscillation, as in shivering, rubbing hands/paws together, pacing. For such activities it seems plausible that the governing mechanisms are encapsulated and require little attention. Minsky's _Society of Mind_ is a good place to look. (Open question how ad hoc they are, perhaps they are in synchrony with preexisting rhythms.) The musicians (and not just the toe tappers and other dancers) are also synchronizing their actions with respect to existing rhythms, even if only to a beat counted out by the leader of the band at the outset (a-one, and a-two . . . ). Where does the initiating musician get the rhythm? Heartbeat? Imagining/ remembering oneself walking? (That is the meaning of `andante'.) Imagining/remembering people dancing? Certainly, once they have started, members of the band must synchronize their playing with one another (ensemble). What happens when the foot tapper is preoccupied with other thoughts? The tapping doesn't slow down, it can't because synchrony is essential to it. Instead, it becomes sporadic. The process itself gets dropped and picked up again. Just so, new musicians have to practice keeping up a steady rhythm despite being distracted by other things (coordinating fingers on the instrument, remembering the words in a song). Their novice performance is typically marked by interrupting and resuming the given rhythm. If a practicing pianist slows down in a passage where the notes are small and close together, it is mostly to coordinate the fingers physically, not to free up processing time. (Preferred way is to slow the whole piece down and play at a constant tempo.) It seems to require a certain amount of attention to maintain a rhythmic behavior, presumably above the threshold required to maintain synchrony. But that's not much, as anyone can attest who has discovered her or his body swaying or falling in step or tapping unawares during a conversation. Rhythm (cyclicity) is an environmental given. Resonance (entrainment) is also a given in physics, ecology, psychology. Music and dance play with these givens. Seems to me that cyclicity and synchrony has survival value in that it helps make organisms predictable to one another. Creatures that become prey are typically those unable to maintain synchrony with their social group because of sickness, etc. Stricking examples of synchrony include flocks of birds, schools of fish. We have recently heard of LIFE emulations of flock behavior involving little processing overhead. Perhaps the problem is not how do individuals synchronize in a flock, but rather how does individuation happen out of the flock, and to what extent. It seems plausible that the experience of being an independent ego that we humans cherish is an illusion. To maintain such an illusion, we ignore counterevidence. A pretty good definition of unconscious behavior. (Say, did you know your foot was tapping?) Bruce Nevin bn@cch.bbn.com <usual_disclaimer>
UUCJEFF@ECNCDC.BITNET (09/19/88)
Date: Thu, 15 Sep 88 14:44 EDT From: UUCJEFF%ECNCDC.BITNET@MITVMA.MIT.EDU Subject: RE: I got rhythm To: ailist@AI.AI.MIT.EDU > >It comes down to this: Different actions require different processing >overhead. So why, no matter what we do, do we perceive time as a constant? >Why do we, in fact, have rhythm? Do we have an internal clock, or a >"main loop" which takes a constant time to run? Or do we have an inadequate >view of consciousness when we see it as a program? >Phil Goetz >PGOETZ@LOYVAX.bitnet Being both an international jazz recording artist and computer programer, with a growing background in AI (but not the AI religion), I will join this jam session on this tune called "I GOT RYTHM". I really dont know how much I can answer Phil's questions, but I can give some perspective on how a musician or drummer or someone with good time views rhythm. Start out by looking at some of the terminology surrounding rythm, we say something is "in a groove" or "in the pocket" or "it swings". The first two imply precision, ease, and continuaty, while "swing" implies motion. All three terms imply "autonomy", and that is so true. When something "swings", the music goes by itself. "Time" is another important word. For musical genres which are known to have advanced forms of rythm, "TIME" is a very mutable characteristic. By laying slightly back of the beat, you make the sound float in the air, and by pushing ahaed slightly, you can give music drive and fire. To be able to master it and use it, I would tend to say it involves all parts of the human psycho physical structure... You certainly excite your nervous system, you need your reflexes to control the muscles that are tapping the foot or playing the instrument, the emotions are involved, and on the mental level, you need to concentrate and use your ability to image things. Then of course there is the musical idea itself behind the whole thing. Certainly if you are lazily tapping your foot and not paying too much other attention, these other charactaristcs will take a lessor role. But to the extent you are tapping good time, you must have the automatism there. Where this comes from, I don't know, but that is how you feel it. Therefore, I would suggest that we do not perceive time as a constant. We don't in ordinary life, and we don't in music. If we are really getting into a piece, we could listen for hours and it will not seem like a long time. I heard a live performance of Stavinsky's La Sacre du Printemp, even though it is 40 minutes, it went by like 10 minutes. Isn't it a famous quote of Einstein when asked to explain relativity, and he said "If you are sitting next to a beautiful girl, hours go by like minutes, but if you are sitting next to ..., minutes seem like hours" Phil asked about programming this. Since I have become disillusioned at how generic most jazz today sounds ( Yes Wynton, that's you) my musical direction has been to make a One Man Digital Band with an Atari ST MIDId to my MIDIcapable trumpet and a variety of synthesizers and drum machines. I have been programming a walking bass line. It reads my trumpet and figures a bass line in real time. If I change keys, It changes keys. If I hold a note. It holds a note. etc... The only way to program rhythm and make it sound "human", is to study humans, identify the slight delays or anticipations, and try to come up with a scheme so it is related to the appropriate information of the other music. This itself is a creative act on the part of the human being. There are no fixed schemes on determining what is approprate, one has to do the research and evaluate the results. Whehher you can get it down to an adaptive filter is anyone's guess. At present there are some people working in this area, and there are even some commercial products out that based on some of the concepts I have presented. There are devices which are designed to take a perfectly timed computer generated drum sync track and massage the pulses so it will give a human feel. On the unit are switchs to make it sound like a 60s Motown feel, a 70s L.A. sound, brazillian, and on and on and on. I think I have said enough, I hope that answer's Phils question. If not I hope that this was interesting otherwise. If not, solid.......... Jeff Beer, UUCJEFF@ECNCDC.BITNET... Chicago Ill.... "I'll play it and tell you what it is later"... Miles Davis
Joseph.Tebelskis@F.GP.CS.CMU.EDU (09/19/88)
To: AIList@AI.AI.MIT.EDU Subject: Re: I got rhythm Date: Fri, 16 Sep 88 03:07 EDT From: Joseph.Tebelskis@F.GP.CS.CMU.EDU In V8 #83, Phil Goetz asks: > It comes down to this: Different actions require different processing > overhead. So why, no matter what we do, do we perceive time as a constant? > Why do we, in fact, have rhythm? Do we have an internal clock, or a > "main loop" which takes a constant time to run? Or do we have an inadequate > view of consciousness when we see it as a program? First you need to realize that the computer is a poor metaphor for the brain. Modern computers are organized around a single CPU through which all the computations must flow, while memory plays a passive and underutilized role -- hence the CPU is called the "bottleneck" of modern computers. As you noted, multitasking slows down individual tasks on such machines. In contrast, the brain has a hundred billion processors (neurons), and its vast memory is active rather than passive. Its various modules operate in parallel, so they don't slow each other down; this is why we can perceive time as a constant no matter what we're doing. Also, the brain does not execute a high-level "program" of instructions: its operation is guided by autonomous physical processes at the neural level. From this neural level emerge all the diverse cognitive phenomena, including rational thought, emotions, and consciousness. However, the only emergent phenomenon which maps well onto our computer programming paradigm is rational thought -- so that's what symbolic AI has always concentrated on. The emergent phenomenon of consciousness is "made of the same stuff" at a low level, but it just cannot be approximated satisfactorily at the symbolic (programming) level. With regard to rhythm and parallelism, I currently visualize the brain as an extremely complex "resonance chamber". At various scales and physical locations within the brain, different subnetworks can be resonating in different ways. The simplest kind of resonance would be a cyclical reverberation of activity at a characteristic frequency; such a pulsing signal could control your foot as you tap out a rhythm. More complex types of resonance may simultaneously be in operation elsewhere in the brain, controlling unrelated cognitive tasks such as doing a math problem. I suspect that subnetworks of the brain use complex resonance patterns to symbolically represent brief progressions of events, such as perceptual sequences, fast motor procedures, and internal state transitions. Such temporally encoded symbols, recursively telescoped together in the "resonance chamber" of the brain, may account for the natural emergence of a hierarchy of symbolic representations for event progressions spanning arbitrary time scales. It is also conceivable that resonant representations avoid interfering with each other in the brain just as physical waves do, by superposition. Joe Tebelskis, connectionist (jmt@f.gp.cs.cmu.edu)
bert@aiva.edinburgh.ac.UK (Bert Hutchings) (09/19/88)
From: Bert Hutchings <bert%aiva.edinburgh.ac.uk@NSS.Cs.Ucl.AC.UK>
Date: Fri, 16 Sep 88 09:59 EDT
To: ailist <@NSS.Cs.Ucl.AC.UK:ailist@kl.sri.com>
Newsgroups: comp.ai.digest
Subject: Re: I got rhythm
References: <19880915011053.7.NICK@HOWARD-JOHNSONS.LCS.MIT.EDU>
Organization: AI Applications Institute, Univ. of Edinburgh, UK
Summary: Me too, but not everybody
In article <19880915011053.7.NICK@HOWARD-JOHNSONS.LCS.MIT.EDU> Phil Goetz
asked "Why do we have rhythm? . . . Why do we, in fact, have rhythm?"
Most of us have, but... My wife taught music to young schoolchildren and
found an occasional exception. We know one rhythm-deaf adult too, unable
to keep a beat, or to distinguish a regular one from a slightly irregular
one. I estimate between 1/50 and 1/200 of people have this condition.mgresham@dscatl.UUCP (Mark Gresham) (09/26/88)
---- Forwarded Message Follows ---- Return-path: <@AI.AI.MIT.EDU,@KL.SRI.COM:dscatl!mgresham@GATECH.EDU> Received: from AI.AI.MIT.EDU by ZERMATT.LCS.MIT.EDU via CHAOS with SMTP id 195054; 18 Sep 88 22:10:01 EDT Received: from KL.SRI.COM (TCP 1200200002) by AI.AI.MIT.EDU 18 Sep 88 22:16:17 EDT Received: from gatech.edu by KL.SRI.COM with TCP; Sun, 18 Sep 88 19:08:37 PDT Received: from dscatl.UUCP by gatech.edu with UUCP (5.58/7.3.GT) id AA06164; Sun, 18 Sep 88 22:04:14 EDT Received: by dscatl.UUCP (smail2.5) id AA18893; 18 Sep 88 21:18:53 EDT (Sun) Path: dscatl!mgresham From: dscatl!mgresham@gatech.edu (Mark Gresham) Newsgroups: comp.ai.digest,rec.music.classical Subject: I got rhythm Message-Id: <11148@dscatl.UUCP> Date: 19 Sep 88 01:18:45 GMT Organization: Digital Systems Co. , Atlanta Lines: 52 In a recent article <on comp.ai.digest> PGOETZ@LOYVAX.BITNET writes: >Here's a question for anybody: Why do we have rhythm? > >Picture yourself tapping your foot to the tune of the latest Top 40 trash hit. >While you do this, your brain is busy processing sensory inputs, controlling >the muscles in your foot, and thinking about whatever you think about when >you listen to Top 40 music. >[...text deleted...] >It comes down to this: Different actions require different processing >overhead. So why, no matter what we do, do we perceive time as a constant? The fact is, we *don't*. (Take it from a musician!) Generally people have a quite erratic perception of time. Th perception (the top 40 example) is one of constancy in relationship to some other perceived event be believe to be constant (or assume is so). Hence, the "beats" in the music (which we deem to be regular) are giving us fresh input which we use to "correct" our foot tapping. >Why do we, in fact, have rhythm? Do we have an internal clock, or a >"main loop" which takes a constant time to run? Or do we have an inadequate >view of consciousness when we see it as a program? > >Phil Goetz >PGOETZ@LOYVAX.bitnet Try this experiment. Or several of you try it. Take a stopwatch (digital is preferable because silent). Don't look at it or any other clock, and don't count; press the start button. Then, when you think five minutes are up, stop it. Look at the watch and see how you did. I know of one percussionist who is said to be quite accurate. If you are really concentrating on "the passage of time" --genuinely trying to be aware of it--my guess is that you'll start to sweat (or otherwise become uncomfortable) after about 40 seconds or so. It takes quite a bit of discipline to empty your mind enough to successfully do that. Try it. Invent other similar experiments. Let me know what you discover. --Mark Gresham (please e-mail or post to rec.music.classical) ++++++++++++++++++++++++++++++++++++++++++ Mark Gresham Atlanta, GA, USA UUCP: ...!gatech!dscatl!mgresham INTERNET: mgresham@dscatl.UUCP ++++++++++++++++++++++++++++++++++++++++++