Terms and Concepts A critical period: a time during an organism’s life span when it is more sensitive to environmental influences or stimulation than at other times during its life.
•Critical period: - begins and ends abruptly
- period beyond which a phenomenon will not appear
•Sensitive period:
- begins and ends gradually - period of maximal sensitivity
•Window of opportunity:
- popular metaphor
- introduced by P. Bateson, 1978 in his critique
•Questions:
- How long does the critical period last?
- When does the plasticity of the brain come to an end? Lenneberg's (1967) Critical Period Hypothesis
Critical Period Hypothesis
Lenneberg theorized that the acquisition of language is an innate process
determined by biological factors which limit the critical period for acquisition of a language from roughly two years of age to puberty.
Lenneberg believed that after lateralization (a process by which the two sides of the brain develop specialized functions), the brain loses plasticity.
Lenneberg claimed that lateralization of the language function is normally completed at puberty, making post adolescent language acquisition difficult.
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Studied Scenarios of the Critical Period Those who believe in it say…. Those who DON'T believe in it argue… More rapid recovery in children is due to the fact that a different side of the brain took over the function in a child; adults' brains are already fully developed so this isn't possible. Children's brains were able to recover from this much faster than an adult with the same injuries. Childhood Aphasia (an Because the brain heals so quickly when young, injury to the brain) this must be the critical period for learning language. Second Language Acquisition Second language acquisition doesn't Long term mastery of a second language necessarily have anything to do with first decreases as age increases. Because children can language acquisition. Just because one can pick up a second language faster, this must be acquire a second language faster does not because they are still in their critical period. mean he couldn't acquire it outside of his critical period. Studies find that these children do The older a child is when he starts learning sign eventually acquire sign language language, the harder of a time he has acquiring proficiency although it does take longer to it. This must mean that he has missed his critical learn. This refutes the critical period period for learning language. hypothesis saying that one can learn language at any age. It is not certain if children in cases of If the child was rescued before the age of 7, extreme deprivation have trouble learning much greater gains were made in acquiring language because they have missed their language. This must be because a child is still in so-called \"critical period\" or if it is because his critical period before the age of 7. of the extreme trauma they have experienced. Deaf children with hearing parents Cases of Childhood extreme deprivation Feral Children •See the classroom handout •Questions:
- Look at the ages at which the children were first exposed to
language. Do you think the evidence supports the idea of a critical period? If so, at what age do you think it ends?
- Do you think researchers should consider other factors besides
age in studying delayed language acquisition? If so, what are they?
•David Skuse (1993) draws the following conclusions from the language deprivation data:
- In adverse childhood circumstances, language seems more
vulnerable than other cognitive faculties.
- In cases of deprivation, speech appears to be more retarted than
comprehension. It develops more slowly after discovery. - Interpersonal contact makes an important contribution to the
speed and success of late language development
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Genie: A study of a young girl who was deprived of language in her early years BACKGROUND
• Her parents had abused her and kept her locked up for most of her 13 years until she was discovered.
• She had been kept in a small room tied to her potty chair. • She was not allowed to speak or make sounds. • She was only given baby food and cereal to eat.
• She had been to the doctor one time in her childhood and there was no sign or retardation in her first 3 years of life.
• When she was admitted to the hospital in November of 1970, she was 54 inches tall and weighed only 62 pounds.
• She could not stand, chew solid food, and couldn't make sounds.
RESULTS OF TESTS ON GENIE
• At first, Genie was unwilling to cooperate. Researchers had to wait 11 months to run tests therefore making it hard to truly assess Genie's linguistic capabilities.
• At first, it was clear Genie could understand more than she was able to speak. • Slowly, over 2 years, she began to understand more and more.
• She finally picked up the difference between singular and plural nouns, negative and positive sentence distinctions, possessive constructions, a few prepositions, and some modifications.
CONCLUSIONS BASED ON TESTS RUN
ON GENIE CONCERNING THE CRITICAL PERIOD HYPOTHESIS
• It is unclear if her inability to learn was due to the fact that she had missed her critical period, or the fact that she had undergone extreme trauma as a child.
• It is also hard to assess this case because researchers weren't able to test her immediately upon discovery to really get a grasp for her language acquisition skills early on. They had to wait until she was ready to cooperate. In that window, Genie could have picked up more language or less than was accounted for. Critical Period hypothesis and the SLA The hypothesis is:
- That the plasticity of the brain permits younger learners to
acquire a second language much more successfully than adult ones;
- That the universal grammar which permits us to acquire our fist
language is no longer available after a certain age.
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An influential study by Johnson and Newport (1989) reported results highly consistent with the critical period hypothesis. The study is widely cited as authoritative evidence for a critical period in L2 acquisition. In their study of native speakers of Chinese and Korean who came to the United States at ages ranging from 3 to 39 years old, they asked subjects to identify grammatical and ungrammatical sentences that were presented in the auditory mode. The reported that prior to age 15, there was a very strong negative correlation with age but after age 15, there was no correlation with age (satisfying Conditions 1 and 2); in addition, the adult learners showed great variability in learning outcomes whereas the child learners did not (Condition 4).
A minute paper:
The Critical Period Hypothesis for learning a first language and the reasons I believe and don't believe in it.
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