168 THE HUMAN USE OF HUMAN BEINGS
for the totally deaf, and that he would like to hear my views on the subject. I gave my views, and it turned out that we were of much the same opinion. We were aware of the work that had already been done on vis- ible speech at the Bell Telephone Laboratories, and its relation to their earlier work on the
Vocoder.
We knew that theVocoder
work gave us a measure of the amount of information which it was necessary to trans- mit for the intelligibility of speech more favorable than that of any previous method. We felt, however, that visible speech had two disadvantages; namely, that it did not seem to be easy to produce in a portable form, and that it made too heavy demands on the sense of vision, which is relatively more important for the deaf:
person than for the rest of us. A rough estimate showed that a transfer to the sense of touch of the principleI
used in the visible-speech instrument was possible, and this we decided should be the basis of our apparatus. We found out very soon after starting that the inves tigators at the Bell Laboratories had also considered the possibility of a tactile reception of sound, and had included it in their patent application. They were kind enough to tell us that they had done no experimental work on it, and that they left us free to go ahead on our researches. Accordingly, we put the design and devel opment of this apparatus into the hands of Mr. Leon Levine, a graduate student in the Electronics Labora tory. We foresaw that the problem of training would be a large part of the work necessary to bring our de- vice into actual use, and here we had the benefit of the counsel of Dr. Alexander Bavelas of our Depart ment of Psychology.The problem of interpreting speech through another sense than that of hearing, such as the sense of touch, may be given the following interpretation from the point of view of language. As we have said, we may roughly distinguish three stages of language, and two intermediate translations, between the outside world
CYBERNETICS AND SOCIETY 16g and the subjective receipt of information. The first stage consists in the acoustic symbols taken physically as vibrations in the air; the second or phonetic stage consists in the various phenomena in the inner ear and the associated part of the nervous system; the third or semantic stage represents the transfer of these symbols into an experience of meaning.
In the case of the deaf person, the first and the third stages are still present, but the second stage is missing. However, it is perfectly conceivable that we may re place the second stage by one by-passing the sense of hearing and proceeding, for example, through the sense of touch. Here the translation between the first stage and the new second stage is performed, not by a physical-nervous apparatus which is born into us but by an artificial, humanly-constructed system. The translation between the new second stage and the third stage is not directly accessible to our inspection, but represents the formation of a new system of habits and responses, such as those we develop when we learn to drive a car. The present status of our apparatus is this : the transition between the first and the new second stage is well under control, although there are certain technical difficulties still to be overcome. We are mak ing studies of the learning process; that is, of the transi tion between the second and third stages; and in our opinion, they seem extremely promising. The best re sult that we can show as yet, is that with a learned vocabulary of twelve simple words, a run of eighty ran dom repetitions was made with only six errors.
In our work, we had to keep certain facts always in mind. First among these, as we have said, is the fact that hearing is not only a sense of communication, but a sense of communication which receives its chief use in establishing a
rapport
with other individuals. It is also a sense corresponding to certain communicative activities on our part: namely, those of speech. Other uses of hearing are important, such as the reception of170 THE HUMAN USE OF HUMAN BEINGS
the sounds of nature and the appreciation of music, but they are not so important that we should consider a
person as socially deaf if he shared in the ordinary, in terpersonal communication by speech, and in no other use of hearing. In other words, hearing has the prop erty that if we are deprived of all its uses except that of , speech-communication with other people, we should still be suffering under a minimal handicap.
For the purpose of sensory prosthesis, we must con sider the entire speech process as a unit. How essential this is is immediately observed when we consider the speech of deaf-mutes. With most deaf-mutes, a training in lip-reading is neither impossible nor excessively dif ficult, to the extent that such persons can achieve a
quite tolerable proficiency in receiving speech-mes sages from others. On the other hand, and with very few exceptions, and these the result of the best and '
most recent training, the vast majority of deaf-mutes, though they can learn how to use their lips and mouths to produce sound, do so with a grotesque and harsh intonation, which represents a highly inefficient form of sending a message.
The difficulties lie in the fact that for these people the act of conversation has been broken into two en tirely separate parts. We may simulate the situation for , the normal person very easily if we give him a tele phone-communication-system with another person, in which his own speech is not transmitted by the tele phone to his own ears. It is very easy to construct such dead-microphone transmission systems, and they have actually been considered by the telephone companies, only to be rejected because of the frightful sense of frustration they cause, especially the frustration of not knowing how much of one's own voice gets onto the
line. People using a system of this sort are always forced to yell at the top of their voices, to be sure that they have missed no opportunity to get the message I accepted by the line.
CYBERNETICS AND SOCIETY