In the 1950s, scientists began studying early language development in conjunction with cognitive science. To this day, the two are highly interrelated as linguists continue to unravel the mysteries of how children acquire language. The nature versus nurture debate has evolved over the years, and the latest research reveals that the modularity of the brain, with its different modules and specific processes, suggests that the various theories of language development can coexist.
Behaviourist psychologists in the 1950s observed how animals could be trained by habit and conditioning. In his book "Verbal Behavior" (1957), B. F. Skinner proposed that children learnt language in a similar fashion. Under behaviorism, children first imitate what adults say. This mimicry is either positively or negatively reinforced with social conditioning. If the children speak correctly, they are praised. If they demand food, they are fed. Thus they are conditioned to retain their successful utterances and discard the unsuccessful.
Soon after "Verbal Behavior" was published, Noam Chomsky challenged its ideas and asserted his own theory that language was biologically determined and that all babies were born with an innate universal grammar. Nativists posit that all children are equipped with a Language Acquisition Device (LAD) that predisposes them to understand and develop language. Chomsky based this on the observation that a kitten and baby that received the same linguistic input would not learn language in the same way.
In the mid-1970s, Jerome Bruner proposed interactionist theory that incorporated both nature and nurture arguments. He asserted that the language input a child receives from his primary caregivers forms a support system that works with his predisposition to language. Social interaction and repeated situations supply the mind with information that works with the innate grammar in order to "crack the code." Thus, language develops through an interaction with the environment as input is processed and incorporated. Most important, language acquisition is driven by the child's desire to communicate and interact with others.
Modularity of the Mind
Neuroscience reveals that the brain is composed of modules that process information differently--visual, auditory and linguistic. Cognitive scientists can study how individual modules process information, but they cannot yet understand how information from multiple modules is integrated in the central processor. However, there is evidence that the linguistic module is itself made of smaller components, each with its own specific task. Thus, some scientists posit that certain linguistic components may rely on the environment, while others depend on the child's innate abilities.
Multiple Theory Approach
New research from linguists and cognitive scientists expands our understanding of how the mind processes information, and the latest framework of language development accommodates many previous theories. Different components of language acquisition reveal how social interaction, environment, biologically determined neural structures and cognitive development all play a different part. This multiple theory approach is helpful in studying the language development in children with Down syndrome or in those who are hearing-impaired.