About thirty years ago I was awarded an NIMH grant to study "Rhythms of Communication" and began by acquiring an analyzer projector and professionally made film of Kung Bushmen, Netsilik Eskimo and Maring of New Guinea. I looked first at a clip of three interacting Eskimos and found that there was a postural or gestural movement by someone every ten frames. This suggested an underlying rhythm. When I looked at two Bushmen telling a traditional story with traditional gestures, I found the same shared 10-frame rhythm. Ten frames of sound film (at 24 frames per second) is about .4 second.
Because of the limitations of 24 frames/sec film and with my understanding that speech and gesture are not independently organized, I began to study speech and eventually acquired computer hardware and software that allowed me to convert speech sounds into digitized waveforms at up to 80,000 samples per second and measure intervals to the nearest ten thousandth of a second. Since I had found that movement onsets showed an underlying rhythm, I looked at the intervals between vocal sound onsets. All sounds (vocal or instrumental) produce partials or a harmonic series, and I eventually found, after many years studying more than a dozen languages, that the onsets of vocal units (Stetson called them "motor syllables), like movement onsets, fell on a harmonic of a fundamental 9.52 Hz rhythm. The observation that this same rhythm is found in all speakers in all languages suggests a significance far beyond "Rhythms of Communication" or the serial ordering of speech or movement.
If it is true, as reported (e.g. Sollberger in Biological Rhythm Research, 1965 and R. O. Becker's The Body Electric) that a ±10 Hz rhythm exists in all life and was set pre-historically, it is not surprising that we would not recognize it. Like the air we breath or the gravity that keeps us on the ground, we would take it for granted. But such an endemic aspect of the planet would significantly "organize" relationships, as does gravity or the earth's rotation. Also, given the physicist's recognition of coupled generators or oscillators, that frequency would be precise and stable by virtue of continuing mutual entrainment. This is the rhythm I have found underlying speech and movement and elsewhere. The Fibonacci series, once it was recognized, was found to be an underlying aspect of nature. and those who looked for it, found it in many places. I believe this will be true of the 9.52 Hz rhythm.We generally recognize others by their talk (what they say) and the accompanying body movements/gestures. But this is relatively large-scale. Many creatures have visual and auditory senses far more acute than humans-and some humans (e.g. Australian aborigines) can recognize human tracks in the desert from which they can tell who and how many people had been there. All of us have intuitions or feelings without knowing explicitly where they come from. So, beyond our talk and visible movements, I believe that we are continuously "broadcasting" ourselves in our micro-movements. But when humans acquired language, which could describe/distinguish past and future and give names to things, the micro information (the individual expressive variation) moved out of our explicit awareness.
All sounds have "overtones"-well-studied in acoustics. My 9.52 Hz designation was chosen from the overtone series for two reasons: 1) it is close to the frequency found in the nervous systems of all animals and 2) it is close to the median frequency of Alpha brain waves. (I am now clear that my 9.52 Hz rhythm is not a brain rhythm.) Brain rhythms are quite variable and reflect the output or "evoked potential" of the underlying brain structure. The rhythm I have identified is precise, even across long pauses. I have thought I might find this fixed rhythm somewhere-in the vocal apparatus or perhaps the intercostals. Now I suspect that it may not originate in the organism itself any more than one could find the source of gravity in our physiology.While it was surprising to me that people "in conversation" shared the same underlying rhythm, I now wonder if they need to be "in conversation." One test of this would be to record the talk of two people, each having a conversation with others. It could be that the shared rhythm is not just between two conversing people but embraces all talk and/or behavior.It is well known that two intersecting rhythms or frequencies produce a third frequency. Piano tuners listen for this. This is known as an "alias" frequency. This alias rhythm is seen as a contamination in wave form research. But this third "alias" rhythm, which is produced when two individual expressive rhythms intersect, carries information to each about their relationship.All of science has progressed by looking more and more closely at phenomena. I have looked more closely at the "serial ordering" (i.e. the underlying rhythms) of behavior. I began by looking at the Eskimo and Bushman behavior on film, but at 16, 24, or 30 frames per second. This clearly limits how close one can look. It was not until I discovered the waveform technology that I could look "closely" at one kind of behavior: speech. So far as I know this is the only technology available that allows such micro-analysis of a human behavior. It was limited, for my purposes, to the examination only of "serial ordering," the temporal organizing aspect. And it was that limitation that led to the micro-examination of rhythmic relations where I found the "universality" of the 9.52 Hz rhythm in the intervals between vocal onsets and wherever waveforms show abrupt change, a reflection, I presume, of the motor activity involved.
I have also found, by acquiring speech file at 12,800 and 25,600 samples/sec, that higher frequencies in this overtone series impinge demonstrably and measurably on the sinusoidal shape of wave forms themselves.