Critical Period Hypothesis

Erika PanganibanBSED-ENG1221

What is Critical Period?• It is a “maturational time period during which some crucial experience will have its peak effect on development or learning, resulting in normal behavior attuned to the particular environment to which the organism has been exposed.”

Critical Period Hypothesis

• “Biologically determined period of life when language can be acquired more easily and beyond which time language is increasingly difficult to acquire.”

Historical Background* The critical period hypothesis was first proposed by Wilder Penfield and Lamar Roberts.

* popularized by Eric Lenneberg in 1967 with his famous book Biological Foundations of Language

Historical BackgroundEric Lenneberg

“First language acquisition relies on brain plasticity and can no longer be accomplished once hemispheric development is complete. If language acquisition does not occur by puberty, some aspects of language can be learnt but full mastery cannot be achieved.”

“Brain lateralization at puberty is the mechanism which closes down the brain’s ability to acquire language.”

Brain Plasticity (Neuroplasticity)

• refers to changes in neural pathways and synapses which are due to changes in behavior, environment and neural processes, as well as changes resulting from bodily injury

Brain Lateralization• The longitudinal fissure separates

the human brain into two distinct cerebral hemispheres, connected by the corpus callosum. The hemispheres exhibit strong, but not complete, billateral symmetry in both structure and function

Historical Background• Lenneberg hypothesized in his

book Biological Foundations of Language (1967) that:

* Language acquisition is a biologically constrained learning* Normally acquired during a critical period (early life and puberty)* Outside this period, language acquired through a different learning process or with difficulty

Historical BackgroundHis hypothesis was based on three groups of people:• People who had brain damage through accidents or diseases before puberty• Children with Down’s syndrome• “Wild children”

Historical BackgroundJohnson and Newport (1989)They performed a study on Chinese and Korean immigrants. The subjects’ ages varied upon arrival in the US and the immigrants had to be targeting English as their second language.“The results of testing show a clear and strong relationship between age of acquisition and performance on the test of English grammar.”

Historical Background• Beginning from 4-6 years, there is a gradual decline

in language proficiency until it plateaus for adult learners

• Learners exposed to the language in adulthood show lower performance than those who are exposed in early childhood

• Critical period affects phonology, morphology and syntax, and not the vocabulary and semantic processing.

Historical BackgroundBialystok & Hakuta, 1999

“There is much more than simple transfer from L1 to L2 going on and that indeed there is some sort of reenactment of the L1 acquisition process at work.”

SUPPORTIVE STUDIES

Supportive StudiesGenie was a 13-year-old victim of lifelong child abuse. She had been kept strapped to a potty chair and wearing diapers. She appeared to be entirely without language when she was found at her age of 13. Her father had judged her retarded at birth and had chosen to isolate her, and so she had remained until her discovery.

Supportive StudiesIsabelle, a girl who was incarcerated with her deaf-mute mother until the age of six and a half (pre-pubescent). She also had no language skill, but unlike Genie, she quickly acquired normal language abilities through systematic specialist training.

Critical Period Hypothesis

Neurobiological

Considerations

Cognitive Considera

tions

Affective Considera

tions

Linguistic Considera

tions

Neurobiological Considerations

Hemispheric Lateralization

As the brain matures, certain functions are assigned to either left or right hemisphere

Lenneberg(1967)

begins at around 2 and is completed around puberty

Geschwind (1970) Is completed much earlier

Krashen (1973)

Scovel (1984) Is completed at 5 years old

emerges at birth is evident at 5

is completed at around puberty

Neurobiological ConditionsRight

hemispheric participation

L2 learners, particularly adults, might benefit from more encouragement of right-brain activity in classroom context.

Cognitive Considerations

Affective Considerations

• Egocentricity• Attitudes• Peer pressure

Egocentricity

• Very young children are highly egocentric, they see the world as revolving around them.

• As they get older, they become more aware of themselves as separate entities from the world, and they become more conscious of themselves as they seek to define and understand their self-identity.

• Gradually, they develop inhibitions about this self-identity. They become afraid of exposing their self-doubt.

Egocentric• Thinking only

of oneself, without the regards or feelings of others

Attitude• Negative attitudes can affect success

in language learning. • Very young children are not developed

cognitively to have “attitudes’ towards races, cultures, languages, ethnic groups, etc. Thus, they have no problem learning a second language. A study shows that “children who are transported from Montreal to Berlin will rapidly learn German no matter what they think of the Germans”.

Peer Pressure• Peer pressure children encounter in

second language learning situations is stronger than that experienced by adults.

• Adults are more tolerant of errors in speech, and thus are more easily excused. This may encourage adult learners to “get by’’ as long as they are understood.

• Children are harsher critics of one another’s actions and words, which may push them to try harder in perfecting their second language.

Linguistic Considerations• Bilingualism

Code-switching • Interference between L1 and L2

Solid foundation of L1• Order of acquisition

Creative construction process

Thank you!

References•

http://cse.iitk.ac.in/users/hk/cs784/projects/indrani.pdf

• http://en.wikipedia.org/wiki/Critical_period_hypothesis

• http://ftp.iza.org/dp2575.pdf