Language Development

Food for thought Is language something special evolved in humans? Are there genes specifically for language? How does language interact with other functions of the brain and behavior?

Phonological Development Infants appear to perceive phonemes from many if not all languages from birth By adulthood, people only perceive phonemes from their native language What happens to allow this narrowing to occur?

Categorical perception Example: Color Perception

Review Categorical perception Example: Color Perception

“Filter” hypothesis

Possible mechanisms Synaptic plasticity Ideas? Network formation Experience Expectant or Dependent? Ideas?

Vocabulary Memory Symbol use Probably involves development of language and higher cognitive areas Very little is understood about development

Syntax/Grammar Issues: Nativist, language box or acquired, evolved for other reasons and co-opted Evidence for each

Brain areas thought to be involved in language

What is language like? Is language a special “organ” designed for a special purpose Or, is it an organ that evolved for something else and has been “co-opted” for language?

Evidence for “special organ” view Language seems to be special It seems to be universal in our species Infants learn language despite wild perturbations in the environment Learning theory cannot adequately explain language acquisition

Evidence for “co-opted” model Is there a “language gene”? Other problems co-occur with language problems Children with specific language impairment (SLI) have trouble processing rapidly presented non-linguistic temporally ordered information Language is not localized in the brain early in development (although some precursors are)

Pragmatics How does language interact with social behavior? Language is communication, communication is social People are inconsistent Communication requires rapid and flexible responses to contingencies Aspects of prefrontal cortex are most likely involved in this function

The “social” brain