Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!CCH.BBN.COM!bnevin From: bnevin@CCH.BBN.COM (Bruce E. Nevin) Newsgroups: comp.ai.digest Subject: Re: I got rhythm Message-ID: <19880918192048.4.NICK@HOWARD-JOHNSONS.LCS.MIT.EDU> Date: 18 Sep 88 19:20:00 GMT Sender: daemon@bloom-beacon.MIT.EDU Organization: The Internet Lines: 82 Approved: ailist@ai.ai.mit.edu Date: Thu, 15 Sep 88 09:01 EDT From: Bruce E. NevinSubject: 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