reflected here have interested philosophers for many centuries.
4.1 Theoretical approaches to the study of language acquisition
4.1.1 Classical approaches to epistemology
Table 4.1 summarizes basic properties of two classically opposed approaches to the representation and acquisition of knowledge. They differ in their views of: (a) theultimate sourceof knowledge (either external and led by environmental input or internal, led by the structure of the mind); (b)mechanisms of acquisition; (c)characteristicsof the Initial State, i.e., whether or not innate
“knowledge” of some form exists. Arationalistperspective proposes some innate competence (thus the term “nativist” is often used). In a classical empiricist paradigm, “learning” based on input explains all knowledge; the Initial State therefore is atabula rasa. (See Wilson 1999 for overview.)
These approaches differ in the form of reasoning which they recognize to underlie knowledge acquisition.Induction(building on direct experience of input data) is central to an empiricist paradigm;deduction(which does not depend on experience of data to confirm conclusions) to a rationalist paradigm (table 4.2).
4.1.2 The challenge of language acquisition to classical empiricist
approaches
Acquisition of language is the “jewel in the crown” of cognitive sci- ence, “what everyone wants to explain” (Pinker, cited by Kolata 1987, 133),
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Table 4.1 Approaches to epistemology.
Empiricism Rationalism
(Locke, Berkeley, Hume;
seventeenth century)
(Descartes, Kant; seventeenth, eighteenth centuries)
i. Knowledge is derived from experience of the “outside world.”
i. Knowledge is derived from the structure of the human mind.
“Anything intelligible to us must be made so by rules of the mind”; “appearances in general are nothing outside our representations” (Kant 1781, in Beardsley 1960, 439).
ii. Information is copied (by sensations and images), remembered, associated with other stored
information. Complex ideas result from associating simple ideas.
ii. Many ideas, e.g., time, space, “or,” God, mathematical concepts, infinity, truth, necessity, have nothing essentially sensory about them, and cannot be “copied.”
“. . . bodies are cognized not by the senses or by the imagination, but by the understanding alone” (Descartes, 1637 in Beardsley 1960, 40).
iii. Infant is born as a “tabula rasa.”
iii. Infant is born with certain “innate” ideas; and an active mind which imposes a structure on experience; what is innate is a precondition of what is learned.
“a prioriknowledge . . . absolutely independent of all experience” (Kant, in Beardsley 1960, 376).
and challenges empiricist theories. Because of its infinite creativity, complex- ity and systematicity, knowledge of language cannot be based on simple “pick up,” copy or association of input, and cannot be derived from simple forms of induction.
4.1.2.1 Serial order
Karl Lashley (1948/1951/1960) saw this early. He recognized a funda- mental problem posed by language for empiricist approaches:1relations between units in a patterned sequence – steps of a horse, notes of music, words in a sen- tence – cannot be fully explained by local associations between any or every two elements in the series. Wherever there is serialization of units, the set of units must be organized: “What then determines the order?”2 There must be a higher-order organizer and this requires a cognitive representation (Lashley
1See Bruce 1994 for discussion of historical relation between Lashley’s and Chomsky’s work.
2Piaget and his collaborators (Inhelder and Piaget 1964) also recognized the cognitive problem of serial order in a general sense. They directed crucial studies of “seriation” as a fundamental area of all logical thought, although they did not deal with language in this area.
Table 4.2 Induction/deduction.
INDUCTION DEDUCTION
General inference is drawn from instances which are experienced.
Conclusions are drawn on the basis of premises already known.
Transitive inference
Fido is a dog. Fido barks. Sarah is shorter than Mary.
Rover is a dog. Rover barks. Mary is shorter than Eve.
Therefore: Dogs bark. Therefore: Sarah is shorter than Eve.
or: That swan is white. or: 2+2=4
This swan is white. 3+1=4
Therefore: Swans are white. Therefore: 2+2=3+1 Syllogism
All men are mortal.
Harry is a man.
Therefore: Harry is mortal.
Properties Properties
Synthetic truth: can be disconfirmed by experience.
Analytic truth: can not be disconfirmed by experience.
Conclusion can be rejected without rejecting the premises.
Can reject conlusions only by rejecting at least one of the premises
Often reasoning from particular to general.
Often reasoning from general to particular.
1948/1951/1960, 510).3 Lashley struggled with this problem.4 (See chapter 2, note 4, p. 12.)
4.1.2.2 Chomsky’s review of Skinner
B.F. Skinner (1953) attempted to extend a classical behaviorist model of learning to language in his famousVerbal Behavior.5 His goal was “to pro- vide a way to predict and control verbal behavior by observing and manipulat- ing the physical environment of the speaker” (1957, 547). In his review of this work, Chomsky (1959) showed that the Skinnerian concepts for learning (which included stimulus, conditioned response and reinforcement) do not apply to
3We use the term “cognitive” in a general sense to reflect all computation by the human mind; we consider specifically “linguistic” computation as one component of cognitive computation.
4“[T]he indications which I have cited, that elements of the sentence are readied or partially activated before the order is imposed upon them in expression, suggest that some scanning mechanism must be at play in regulating their temporal sequence. The real problem, however, is the nature of the selective mechanism by which the particular acts are picked out in this scanning process, and to this problem I have no answer” (Lashley 1951/1960, 522).
5On “behaviorism” see Boring 1950, Holyoak 1999.
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language knowledge and behavior. No obvious concept of reinforcement appears to be relevant to language use or knowledge.
1. Our capacity to generate language crucially determines our capacity to perceive language. It appears that we recognize a new item as a sentence not because it matches some familiar item in any simple way, but because it is generated by the grammar that each individual has somehow and in some form internalized. And we understand a new sentence, in part, because we are somehow capable of determining the process by which this sentence is derived in this grammar. (Chomsky1959, 576)
. . . a refusal to study the contribution of children to language learning permits only a superficial account of language acquisition.” (578)
4.1.2.3 Language acquisition vs. language learning
Chomsky’s conclusion led to a distinction between “language learn- ing” and “language acquisition,” recognizing that language is not “learned” in any classical sense of the term but requires computation through cognitive struc- ture. Addressing the question Lashley had struggled with for language, Chomsky identifies a “generative grammar,” a component of the mind/brain, which pro- vides syntax, central to language knowledge. Through detailed theoretical and empirical analyses in linguistics, he argued that knowledge of syntax determines the order of a sentence by generating its structure, i.e., its “secret skeleton.”
4.2 Current approaches to the study of language