Essentially, then, the child was not learning strictly from outside input, but was responding to the outside input from an internal system similar to the "instincts" of other animals. In other words, in looking at the evidence, Chomsky and other nativist theorists concluded that the language acquisition that took place was greater and more efficient than seemed warranted by the language training, direct and indirect, that the child received. In the same way that a baby bird seems to simply "know" migration patterns without being taught clearly and directly, baby humans seem to "know" the rules of appropriate syntax. Again, this is a universal, according to Chomsky, not dependent on any particular language or its grammatical set (1975). (Although Chomsky also contended that there are only certain ways in which a language can develop, this is limited by the hard-wiring of the built-in language capacity.)
For Chomsky, the LAD is basically the hard-wiring of the language capacity while the Universal Grammar is the software or programming. The LAD makes it possible for human beings to acquire language at all, while the Universal Grammar means that language is created and organized only in certain ways. Another important element of Chomsky's theory particularly pertinent to language acquisition is Chomsky's contention that there is a core grammar, which is universal and therefore easier to acquire, and a peripheral grammar, which is language specific and consequently more difficult to acquire (Hadley, 1993).
Finally, an important element of Chomsky's understanding of Universal Grammar is that UG establishes the foundation for language, while experience provides children with an understanding of the parameters or limits of language. According to McLaughlin (1987):
The Universal Grammar constraints the hypothesis th