PSY 369: Psycholinguistics

1. PSY 369: Psycholinguistics Language Acquisition: Critical period?

2. Critical (sensitive) periods • Certain behavior is developed more quickly within a critical period than outside of it. This period is biologically determined. • Examples: • Imprinting in ducks (Lorenz, ; Hess, 1973) • Ducklings will follow the first moving thing they see • Only happens if they see something moving within the first few hours (after 32 hours it won’t happen) of hatching • Binocular cells in humans • Cells in visual system that respond only to input from both eyes. • If these cells don’t get input from both eyes within first year of life, they don’t develop

3. Critical (sensitive) periods • Certain behavior is developed more quickly within a critical period than outside of it. This period is biologically determined. • Some environmental input is necessary for normal development, but biology determines when the organism is responsive to that input. • That “when” is the critical period

4. Critical period for language • Lenneberg (1967) proposed that there is a critical period for human language • It assumes that language acquisition must occur before the end of the critical period • estimates range from 5 years up to onset of puberty

5. Evidence for critical period for language • Feral Children • Children raised in the wild or with reduced exposure to human language • What is the effect of this lack of exposure on language acquisition? • Two classic cases • Victor, the Wild Boy of Aveyron • Genie

6. Victor, The Wild Boy of Aveyron • Found in 1800 near the outskirts of Aveyron, France • Estimated to be about 7-years-old • Considered by some to be the first documented case of autism • Neither spoke or responded to speech • Taken to and studied by Dr. Jean-Marc-Gaspard Itard, and educator of deaf-mute and retarded children • Never learned to speak and his receptive language ability was limited to a few simple commands. • Described by Itard as “an almost normal boy who could not speak”

7. Genie • Found in Arcadia, California in 1970, was not exposed to human language until age 13.5. • Raised in isolation a situation of extreme abuse • Genie could barely walk and could not talk when found • Dr. Susan Curtiss made great efforts to teach her language, and she did learn how to talk, but her grammar never fully developed. • Only capable of producing telegraphic utterances (e.g. Mike paint or Applesauce buy store) • Used few closed-class morphemes and function words • Speech sounded like that of a 2-year-old

8. Genie • By age of 17 (after 4 years of extensive training) • Vocabulary of a 5 year old • Poor syntax (telegraphic speech mostly) • Examples • Mama wash hair in sink • At school scratch face • I want Curtiss play piano • Like go ride yellow school bus • Father take piece wood. Hit. Cry.

9. What Do These Cases Tell Us? • Suggestive of the position that there is a critical period for first language learning • If child is not exposed to language during early childhood (prior to the age of 6 or 7), then the ability to learn syntax will be impaired while other abilities are less strongly affected • Not uncontroversial: Victor and Genie and children like them were deprived in many ways other than not being exposed to language • Genie stopped talking after age 30 and was institutionalized shortly afterward (Rymer, 1993)

10. Effects of the Critical Period • Learning a language; • Under c. 7 years: perfect command of the language possible • Ages c. 8- c.15: Perfect command less possible progressively • Age 15-: Imperfect command possible • In some special cases, we are given a window on the nature of the critical period

11. Effects of the Critical Period • Learning a new language • What if we already know one language, but want to learn another?

12. Effects of the Critical Period • Johnson and Newport (1989) • Native Chinese/Korean speakers moving to US • Task: Listen to sentences and judge whether grammatically correct