Originally published in American Journal of Psychology, Volume 46, pages 145-7, 1934.
S.S. Stevens
Department of Psychology, Harvard University
The behavior of congenitally blind Os in experiments involving judgments of the extension or spatiality of those experiences which originate through hearing is important to the understanding of the nature of certain auditory phenomena. The question of the relation of tonal volume to visual space can be readily resolved if it can be shown that an O having no experience of space is yet able to make judgments of the phenomenal volume of tones.
In the course of an experiment on tonal volume the services of Miss S. V. Fladeland, a congenitally blind instructor at the Perkins Institute for the Blind, were enlisted for the purpose of determining what effect, the absence of visual imagery would have upon an O's ability to equate for volume two tones of different pitch by changing the intensity of one of the tones. This O was familiar with the concepts pitch and intensity but had never heard of volume as a phenomenal dimension of tones. Consequently it was necessary to train her to recognize volume. In order to do this, she was presented with a high tone (3000 cycles) and asked to notice its "size." Then she was given a low tone (200 cycles). She came quickly to understand what was meant by volume, and described the low tone as being "larger" than the high tone. The dependence of volume upon the intensity of the tones was made clear to her in an analogous manner, and she found that she could very easily make two tones equal in volume by changing the intensity of one.
The quantitative results obtained by the process of equating two tones in volume agreed closely with those obtained from normal Os [1]. After a series of 32 judgments it had become possible for this O to abstract the size of the tones from their pitch and loudness without the aid of concrete imagery. Her report subsequent to the experiment was as follows.
"I used an arbitrary basis at first to establish my sense of volume. I compared the tone to a tube, or jet, through which steam passes to produce a sound, and by using my hand as a cup to fit the escaping steam I was able to determine its size. All of the tones used in the experiment would be close to the size of a not-too expanded teacup. The high tones, however, were not only smaller, but they seemed to rise in space."
To the question, "Where were the tones?", she replied that they were on the right arm of the chair, in a position such that she could cup her hand around them. In order to cup her hand around the high tones, she had to raise her hand two or three inches above the arm of the chair. She explained that the raising of her hand for the high tones was probably due to the fact that in teaching speech to blind children she habitually made an upward gesture when she raised her voice.
The significance of the results obtained from this O is that, in the first place, they show that volume is a true phenomenal dimension of tones in that it can readily be observed by an O unaided by visual imagery. Bannister [2], in the course of his argument against the validity of volume as a category of experience, reported the case of an O, blind since the age of three, who "has never been able to experience or to understand the attribute of volume, although it has been suggested to him." It would be interesting to see whether, with systematic training, this O could not be taught to discriminate volume as Miss Fladeland did.
In the second place, the work with Miss Fladeland shows that the systematic identification of tonal volume with the truly spatial aspects of experience must be made with caution. Although the congenitally blind habitually employ the words space, distance, size, etc., it may well be that they understand by them something other than what the same words connote to a person with normal vision. Sir Wm. Hamilton [3] insisted that the observations of Dr. Platner [4] were sufficient proof that the congenitally blind have no concept or experience of space as we know it. The blind, he argued, experience only time and effort or motion, and the distance from one side of the room to the other means to them only so much time and so much movement. In 1844 Hagen put forth a similar argument [5]. In speaking of the congenitally blind he said, "Was uns Raum ist, ist bei ihnen bloss Zeit." More recently Goldstein and Gelb have shown that a patient who lacked all capacity for forming visual imagery was completely devoid of the sense of spatiality [6]. They concluded that through the Tastsinn alone one can never achieve Raumvorstellungen, and that consequently "es gibt eigentlich nur einen Gesichtraum." If this conclusion is true, it must follow that if a person who is incapable of experiencing space is nevertheless able to experience tonal volume, tonal volume is not a spatial experience.
It is a fact, however, that most normal Os report that their judgments of tonal volume are based upon the "space filling" aspect of tones. They also report the use of visual imagery in most instances. As Goldstein and Gelb pointed out, a similar situation is encountered in the case of tactual localization. The argument of these authors was that the persistent presence of visual imagery as a concomitant of tactual experience leads the normal O to believe that touch, as such, has spatial qualities. If the same argument is applied to the discrimination of tonal volumes, we may conclude that it is only because of the presence of a visual surrogate that tones seem to have true phenomenal extent.
Some Os have directly denied the spatiality of the tones whose volume they were successful in judging. For instance, one of Rich's Os reported: "It is a different kind of size from visual size. . . . Space is so visual to me that, when I open my eyes, it seems a sort of folly to me; but when I close my eyes, I feel the massiveness of the tones." [7] In the course of an experiment conducted by the author, one of the Os said: ''There is nothing spatial about volume. I match two. tones; I don't compare two extents. It is more a matter of massiveness than size, because size implies space." This O also reported that he was aware of no visual imagery when he judged volume.
It would seem, then, that there is no good evidence that tones, as such, have truly spatial characteristics, and that one is justified in attributing space or extensity to auditory experience only if he is willing to accept the existence of a spatial surrogate as a sufficient basis.
1. An account of tonal volume as a quantitative function of frequency and intensity for various Os, including the present O, is accepted for later publication in this journal.
2. H. Banister, Auditory theory; a criticism of Professor Boring's hypothesis, this JOURNAL, 38, 1927, 436-440.
3. Sir Wm. Hamilton, Lectures on Metaphysics, II, 1861, 173-175.
4. Ernst Platner, Philosophische Aphorismen, I, 1793, 446.
5. F. W. Hagen, in R. Wagner's HandwOrterbuch der Physiologie, II, 1844, 718. K. Goldstein and A. Gelb, Ober den Einfluss des volstandigen Verlustes desoptischen VorstellungsvermOgens auf des taktile Erkennen, Zsch. f. Psychol., 83, 1920, 1-94.
6. G. J. Rich, A preliminary study of tonal volume, J. Exper. Psychol., 1, 1916, 19 f.