Read 1989 - Seeing Voices Online
Authors: Oliver Sacks
121. There has recently been an educational experiment in Prince George’s County, Maryland, with the introduction of Sign into first grade and preschool education among normal, hearing children. The children acquire it readily and enjoy it, and as they do they show significant improvement of reading and other skills. It may be that this facilitation of reading, of the ability to recognize the forms of words and letters, goes with the enhancement of spatial-analytic ability that occurs with the learning of Sign.
Even when (hearing) adults learn Sign, they too may become conscious of changes in themselves—a disposition to more vivid visual description, enhancements of visual imagery and memory, and often a freer and more direct expressive use of the body. It would be interesting to find out if there occurs to some degree, in such adults, an enhancement of visual evoked potentials such as Neville finds in hearing native signers.
Interestingly, there is
not
a good correlation between ability to learn spoken languages and ability to learn Sign. Some polyglots are taken aback at finding how ‘hard’ it is; and other people, who have never been able to learn another spoken language, may be startled to find how ‘easy’ Sign is. These differences may reflect differing
visual
powers of
individuals
, and have little to do with intellectual powers, or linguistic powers, in general. In adult life, basic visual powers may be capable of only limited enhancement, whereas early training, seemingly, can enhance visual powers in us all.
Very recently, there have been some fascinating observations with regard to the brain’s disposition to sign language when it is exposed to it—in particular, its tendency toward ASL—like, or (in more general terms) Sign-like, forms
whatever
form of sign language it is exposed to. Thus James Paul Gee and Wendy Goodhart have shown dramatically that when deaf children are exposed to signed forms of English (manually encoded English),
but not ASL
, they ‘tend to innovate ASL-like forms with little or no input in that language.’
122
122. Gee and Goodhart, 1988.
This is an astonishing finding: that a child who has never seen ASL nonetheless evolves ASL-like forms.
Elissa Newport and Ted Supalla have shown that children construct grammatically perfect ASL even when they are exposed (as they so often are) to somewhat less-than-perfect ASL—a clear illustration of an innate grammatical competence in the brain.
123
123. Newport and Supalla’s research is discussed in Rymer, 1988.
Gee and Goodhart’s findings go further, by showing that the brain moves inevitably toward Sign-like forms, and will even ‘convert’ non-Sign-like forms
to
Signlike-forms. ‘Sign is closer to the language of the mind,’ as Edward Klima says, and thus more ‘natural’ than anything else when the developing child is called upon to construct a language in the manual mode.
Sam Supalla has provided independent confirmation of these studies.
124
124. Supalla, in press.
Focusing in particular on the sort of devices used to mark grammatical relations (these are all spatial in ASL, but in signed English, as in spoken English, entirely sequential), he has found that deaf children exposed only to signed English
replace
its grammatical devices by purely spatial ones ‘similar to those found in ASL or other natural signed languages.’ Supalla speaks of these as being ‘spontaneously created,’ or evolved.
It has been known for many years that signed English is cumbersome and imposes a strain on those who use it: ‘Deaf people,’ writes Bellugi, ‘have reported to us that while they can process each item as it appears, they find it difficult to process the message content as a whole when all the information is expressed in the sign stream as sequential elements.’
125
125. Bellugi, 1980, pp. 135-136.
These difficulties, which do not diminish with use, are due to fundamental neurological limitations—in particular, of short-term memory and cognitive processing. None of these difficulties occurs with ASL, which with its spatial devices is perfectly adapted to a visual mode, and can be easily signed and understood at high speed. The overloading of short-term memory and cognitive capacity that occurs with signed English in deaf adults is experienced as difficulty and strain. But in deaf children, who still have the capacity to
create
grammatical structures—so Supalla hypothesizes—the cognitive difficulties involved in trying to learn signed speech force the children to create their own linguistic structures, to create or evolve a spatial grammar.
If deaf children are exposed only to signed English, Supalla has further shown, they may exhibit ‘impaired potential for natural language acquisition and processing,’ impairment of their capacity to create and comprehend grammar, unless they are able to create their own linguistic structures. Fortunately, being children, and still at a ‘Chomskian’ age, they
are
able to create their own linguistic structures, their own spatial grammar. They resort to doing this in order to ensure their own linguistic survival.
These findings on the spontaneous origination of Sign, or Sign-like linguistic structures, in children may cast a very important light on the origin and evolution of Sign in general.
For it appears as if the nervous system, given the constraints of language in a visual medium, and the physiological limitations of short-term memory and cognitive processing,
has
to evolve the sort of linguistic structures, the sort of spatial organization, we see in Sign. And there is strong circumstantial support for this in the fact that all indigenous signed languages—and there are many hundreds, all over the world, which have evolved separately and independently wherever there are groups of deaf people
126
—all indigenous signed languages have much the same spatial structure.
126. It should be made clear that no sign language can be considered as ‘primitive’ compared to any other sign language (just as no extant spoken language is more ‘primitive’ than any other). But it is sometimes felt in the United States that ASL is by far the best sign language in the world—the best organized, the richest, the most expressive, etc.—an attitude which has led to a certain amount of ASL ‘imperialism’ (causing other native sign languages, in smaller countries, to defer to, and even be replaced by, ASL). But this is a hierarchic concept. In fact, all languages, whether signed or spoken, no matter how new, or how limited their geographic distribution, have the same potentials, the same range of possibility—none can be dismissed as ‘primitive’ or ‘defective.’ Thus British Sign Language is fully the equal of ASL; Irish Sign Language is fully the equal of both; and so too is Icelandic Sign Language (even though there are only seventy deaf people in Iceland).
None of them resembles signed English, or signed speech, in the least. All have, beneath their specific differences, some generic resemblance to ASL. There is no universal sign language, but there are, it seems, universals in all sign languages, universals not of meaning, but of grammatical form.
127
127. The hundreds of sign languages that have arisen spontaneously all over the world are as distinct and strongly differentiated as the world’s range of spoken languages. There is no one universal sign language. And yet there may be universals
in
signed languages, which help to make it possible for their users to understand one another far more quickly than users of unrelated spoken languages could understand each other. Thus a monolingual Japanese would be lost in Arkansas, as a monolingual American would be lost in rural Japan. But a deaf American can make contact relatively swiftly with his signing brothers in Japan, Russia, or Peru—he would hardly be lost at all. Signers (especially native signers) are adept at picking up, or at least understanding, other signed languages, in a way which one would never find among speakers (except, perhaps, in the most gifted). Some understanding will usually be established within minutes, accomplished mostly by gesture and mime (in which signers are extraordinarily proficient). By the end of a day, a grammarless pidgin will be established. And within three weeks, perhaps, the signer will possess a very reasonable knowledge of the other sign language, enough to allow detailed discussion on quite complex issues. There was an impressive example of this in August 1988, when the National Theater of the Deaf visited Tokyo, and
joined
the Japan Theater of the Deaf in a joint production. ‘ ‘The deaf actors in the American and Japanese acting companies were soon chatting,’ reported David E. Sanger in
The New York Times
(August 29,1988), ‘and by late afternoon during one recent rehearsal it became clear they were already on each other’s wavelengths.’
There is good reason to suppose (though the evidence is circumstantial rather than direct) that general linguistic competence is genetically determined and is essentially the same in all human beings. But the particular form of grammar—what Chomsky calls ‘surface’ grammar (whether this be the grammar of English or Chinese or Sign)—is determined by the experience of the individual; it is not a genetic endowment but an epigenetic achievement. It is ‘learned,’ or perhaps one should say, for we are dealing with something primitive and preconscious, it
evolves
through the interaction of a general (or abstract) linguistic competence and the particularities of experience—an experience which, in the deaf, is distinctive, indeed unique, because it is in a visual mode.
What Gee and Goodhart, and Samuel Supalla, observe
is
an evolution, a startling (and radical) modification of grammatical forms, under the influence of this visual necessity. They describe a change, a grammatical form changing visibly before the eyes, becoming spatialized, as signed English is ‘turned into’ an ASL-like language. They depict an evolution of grammatical forms—but an evolution occurring within the course of a few months.
Language is actively modified, the brain itself is actively modified, as it develops a wholly new capacity to ‘linguisticize’ space (or to spatialize language). As the brain does this, it simultaneously develops all the other visual-cognitive, but nonlinguistic, enhancements that Bellugi and Neville have described. There must be physiological and (could we but see them) anatomical shiftings and reorganizations in the micro-structure of the brain. Neville conceives the brain as having, at first, a great neuronal redundancy and plasticity, and of this being subsequently ‘pruned’ by experience, here reinforcing synapses, connections between nerve cells, there inhibiting or suppressing them, according to the competing pressures of different sensory inputs. It is clear that genetic endowment alone cannot explain the full connectional complexity of the nervous system—whatever invariants are predetermined, additional diversity emerges during development. This postnatal development, or epigenesis, is the central concern of Jean-Pierre Changeux’s work.
128
128. Changeux, 1985.
But a more radical suggestion, indeed a wholly different way of thinking, has recently been put forward by Gerald Edelman.
129
129. Edelman, 1987.
The unit of selection for Changeux is the individual neuron; the unit of selection for Edelman is the neuronal group, and it is only at this level, with selection of different neuronal groups or populations under competitive pressures, that
evolution
(as distinct from mere growth or development) may be said to occur. This allows Edelman to produce a model which is essentially biological, indeed Darwinian, in nature.
130
130. This point is made by Francis Crick in a recent article on neural networks (Crick, 1989). Crick describes a computational model, NET-talk, which, given an English text it has never seen before, babbles at first, having only random connections, but soon
learns
to pronounce words with 90 percent accuracy; thus, Crick observes, ‘it has learned the rules of English pronunciation, which are notoriously not straightforward, in a tacit manner, from examples only, and not because the rules have been explicitly embodied in some program.’ What might seem to be a ‘Chomskian’ task, albeit a trivial one compared to the achievement of grammar, is here accomplished by a mere network of artificial neurons with initially random connections. There has been great excitement recently about such neural networks, but the actual mechanisms evolved by the brain, Crick feels, are quite unknown to us at this point, and liable to be of an altogether different (and more ‘biological’) order and nature.Addendum 1990
: Such a network has very recently been devised (by B.P. Yuhas) to read lips, by estimating vowels based on mouth shape, and positions of lips, teeth, and tongue. This neural network, combined with conventional speech recognition systems, may one day produce a system which is fast enough and flexible enough for practical use (
Science
247:1414, March 23, 1990).
Darwin conceives of natural selection occurring in populations in response to environmental pressures. Edelman sees this as continuing
in the organism
(he speaks here of ‘somatic selection’), determining the individual development of the nervous system. The fact that
populations
of nerve cells, and not merely individual cells, are involved allows far more complex potentials for change.
Edelman’s theory provides a detailed picture of how neuronal ‘maps’ can be formed, which allow an animal to adapt (without innate programs or instruction) to wholly new perceptual challenges, to create or construct new perceptual forms and categorizations, new orientations, new approaches to the world. This is precisely the situation of the deaf child: he is flung into a perceptual (and cognitive and linguistic) situation for which there is neither genetic precedent nor teaching to assist him; and yet, given half a chance, he will develop radically new forms of neural organization, neural mappings, which will allow him to master the language-world, and articulate it, in a quite novel way. It is difficult to think of a more dramatic example of somatic selection, of neural Darwinism, in action.
131