source file: mills2.txt Subject: Octave Generalization From: John Chalmers There has been some recent discussion of non-octaval scales and the perception of such on the List by McLaren, Morrison, etc. Some time ago Paul Erlich sent me an unpublished paper with a reference to rats' perceiving the octave (Blackwell, H. and H. Schlosberg. 1943. "Octave Generalization, Pitch Discrimination and Loudness Threshold in the White Rat." J. Experimental Psychology 33: 407.) I have been exchanging email with James Murray, a cognitive neurobiologist at UCSD who has done studies of hearing in animals. He was kind enough to do a quick & dirty literature search for recent papers on octave generalization. The most relevant of the half dozen or so are those below (the others mainly refer to starlings and dolphins, which are, perhaps, not the primary audience for xenharmonic music): " Sergeant, Desmond. "The octave: Percept or concept." Psychology of Music, 1983, v11 (n1):3-18. "Abstract: Investigated octave generalization in 90 4-9 yr olds by means of responses to matching tasks based on judgments of similarity. In E PI, 54 Subjects, presented with 5 tone bars differing in pitch within an octave range, were asked to match a 6th bar to 1 of the 5 bars. Results indicate a significant tendency for tonal similarity to be judged as proximity of pitch. In Exp II, the probability of judgment on the basis of pitch proximity was reduced by providing an array in which the 5 tones were clustered together in pitch. In Exp III, 36 Subjects were asked to arrange 2 sets of 5 tone bars each so that the arrays were similar. Although a few Subjects completed the task, no significant ability to solve this octave transportation task was found. It is concluded that a concept of "octaveness" is developed experientially and is not of perceptual origin. "D'Amato, M. R.; Salmon, David P. "Tune discrimination in monkeys (Cebus apella) and in rats." Animal Learning & Behavior, 1982 May, 10(n2):126-134. "Abstract: Six 10-18 yr old monkeys and 8 female albino rats were trained on an operant discrimination employing structured auditory stimuli (tunes). Rats acquired the tune discrimination very rapidly and considerably faster than monkeys. Both species generalized the discrimination across intensity and octave transformations. Discriminative performance remained at a high level when only the 1st halves of the tunes were presented, but substantially less generalization occurred to the 2nd halves. Rats trained with tones (broken or steady) required 3-4 times more training to reach criterion than did the rats trained wth tunes. The potential of structured auditory stimuli for investigations of information-processing mechanisms is pointed out. " While the experimental designs, criteria, and stimuli were undoubtedly very different, it appears that female rodents perceive octaves more readily than apes and human children. The evolutionary and aesthetic implications of these findings are somewhat unclear to me. Anyway, does anyone know of any extant musical culture which does not recognize octave equivalence (including stretched or shrunk octaves)? The only counter-examples I can think of might be Eastern Orthodox chant, which is sometimes based on chains of tetrachords or divided fifths. Some Russian chant may be based on chains of divided thirds, but, of course, the octave may still appear among the intervals and choruses may still double in octaves. Some Andean panpipes seem to be tuned to an additive scale, yet the pipes themselves overblow in octaves rather than twelfths due to their deliberate and unusual construction. Does anyone have more specific (especially contradictory) information? (Enrique?) --John