Why is language unique to humans?
Linguists. psychologists. and neuroscientists have studied language acquisition with the tools and models available to their respective fields. Linguists elaborated some of the most sophisticated theories to account for how this unique human competence arises in the infants' brains. Chomsky (1980) formulated the parameter setting theory (hereafter. PS) to account for how infants. on the basis of partial and noisy language input, acquire grammar. PS assumes that infants are born with "knowledge" of Universal Grammar (UG).This includes both genetically determined universal principles and binary parameters. Universal principles describe the properties common to all natural languages. Binary parameters capture the grammatical properties on which natural languages differ from one another. The linguistic input determines the particular value of a parameter. PSpostulates that exposure to the surround- ing language determines how the parameters ofUG are set.1
We acknowledge that PS has many virtues. It addresses the problem of language acquisition without making unjustified but common simplifications. for example. that imitation is the privileged mechanism responsible for the emergence of linguistic competence. The theory, furthermore, is quite appeal- ing because it assumes. realistically, a biological perspective. namely. that the child is equipped with a species-specific mechanism to acquire natural lan- guage. Moreover. the PS theory has been formulated with sufficient detail and precision as to make it easy to falsitY. In contrast, proposals that assume that language is acquired by means of a general learning device appear more difficult to support. Criticisms of proposals according to which general learning mechan- isms are sufficient to explain language acquisition have been given by many
Topics in Integrative Neuroscience: From Cells to Cognition. ed. James R. Pomerantz. Published by Cambridge University Press. © Cambridge University Press 2008.
theoreticians (see Chomsky, 1959; Fodor, 1975; Lenneberg et al., 1964; Pinker, 1984).
All theories agree that at least parts of grammar have to be learned. What distinguishes the different positions is the scope and nature of learning. How does the learning proceed? PS assumes an initial state characterized by knowl- edge specific to language. In contrast, theoreticians who favor a general learning mechanism, assume that the initial state is characterized by learning principles that apply to all areas in which the organism gains knowledge. PS has the advantage that it is rather easy to falsify. If syntax cannot be acquired given the normal input, then PSwould have to be abandoned. Indeed, if PS turns out to be misguided, badly informed, or incorrect, another theory will have to be formulated and evaluated. This is far from being an exceptional situation. Rather, it is one that is obtained in all scientific domains. In contrast, recent generic learning accounts (see...