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The Critical period
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The girl reportedly was still wearing diapers when a social worker discovered the case two weeks ago. Raised in isolation, "Genie" was a wild child, uncivilized, barely able to walk or talk. This is the scene of the crime. The child was locked in a room and tied to a potty chair for most of her life. Completely restrained, she was forced to sit alone day after day and often through the night. She had little to look at and no one to talk to for more than ten years. Genie was about to test an idea important to science and society: that a nurturing environment could make up for even the most nightmarish of pasts. I was captivated by her. I was not the last person to become captivated by her. The story, as we began to learn about it, was sort of one of the things, of course, that would reach out and grab you anyway. But she had a personal quality that seemed to elicit rescue fantasies, and this in a group of people who were interested in taking care of kids and who specialized in early childhood, who were going to be sort of powered by rescue fantasies anyway. She reached out and grabbed lots of us. Shurley wanted to assess how well Genie had survived her long years of isolation. He directed the team to gather information on her brain waves. For four nights running, they wired Genie to instruments that measured the electrical activity in her brain while she slept. What they found was an unusually high number of so-called sleep spindles, the dense bunching patterns that look like spindles on a spinning machine. This was an abnormal brain wave pattern. The sleep studies raised a question that would puzzle the Genie team for years. Was Genie brain damaged from her years of abuse, or had she been retarded from birth? When Genie was a baby, her father apparently decided she was retarded. He insisted on keeping her isolated because of that. Authorities pieced together these few facts in the early weeks. Genie's strange family circumstances made it hard to learn more. Genie's mother, weak and nearly blind, claimed that she, too, had been a victim of her domineering husband. Genie's father, shortly after authorities discovered Genie, shot and killed himself. The suicide only added to the interest in Genie's case. She was a prize patient, and in the months to come, the number of visiting scientists increased. Genie's new celebrity status marked the beginning of a debate that would intensify over time: How should her case be handled? James Kent's plan was the first to be adopted. He believed Genie could get better if she were allowed to form relationships, and he was encouraged when she started to do so. Up until one particular day, Genie didn't seem to respond in any special way to my coming or going, at the end of our sessions. Then one day, when I'd left, her expression changed from happy to sad to indicate that there was some sadness in the separation for her. And it was the first indication that I had that we were beginning to form this relationship. I thought as long as she had the capacity to form attachments, she had the capacity to learn; she had the capacity to get better. She was difficult to understand, but Genie was repeating words. Genie was beginning to talk.


How does a child learn language? How is it that when we were children, we learned what words meant and why our moms and dads said them? When did we actually start to really understand?

If you have ever asked these questions, you have come to the RIGHT site! On this site I will be discussing:

1. The Critical Period Hypothesis for learning a first language and the reasons I believe and don't believe in it.

2. A case study of a girl named Genie. She was deprived of language during this so-called "critical period."

1. The Critical Period Hypothesis in first language acquisition: Fact or Fiction?



2. Genie: A study of a
Studied Scenarios of the Critical Period
Those who believe in it say….
Those who DON'T believe in it argue…
Childhood Aphasia (an injury to the brain)
Children's brains were able to recover from this much faster than an adult with the same injuries. Because the brain heals so quickly when young, this must be the critical period for learning language.
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.
Second Language Acquisition
Long term mastery of a second language decreases as age increases. Because children can pick up a second language faster, this must be because they are still in their critical period.
Second language acquisition doesn't necessarily have anything to do with first language acquisition. Just because one can acquire a second language faster does not mean he couldn't acqure it outside of his critical period.
Deaf children with hearing parents
The older a child is when he starts learning sign language, the harder of a time he has acquiring it. This must mean that he has missed his critical period for learning language.
Studies find that these children do eventually acquire sign language proficiency although it does take longer to learn. This refutes the critical period hypothesis saying that one can learn language at any age.
Cases of Childhood extreme deprivation
If the child was rescued before the age of 7, much greater gains were made in acquiring language. This must be because a child is still in his critical period before the age of 7.
It is not certain if children in cases of extreme deprivation have trouble learning language because they have missed their so-called "critical period" or if it is because of the extreme trauma they have experienced.
young girl who was deprived of language in her early years.

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 w
as 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.


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.

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.


Drawing Conclusions about the Critical Period Hypothesis

As you can see, the Critical Period Hypothesis is just that-a hypothesis! It cannot be proven through the tests that have been run in the above scenarios, or tests run on Genie. So, judge for yourself! Do YOU think there is a Critical Period for learning language? Hopefully this site has helped to answer this question and many more!!

Back to the Critical Period Hypothesis Page


The Linguistic Development of Feral Children in Reference to the Critical Period

By Emily Barnby

One of the most appealing aspects of neurolinguistics is the limitless levels of comprehension that can be achieved. No matter how much researchers discover and understand, there is still centuries of development yet to be undertaken. The brain is the most complex of mechanisms, and its multiple levels, functions, and areas of specialization provide the mainframe of control for the basis of life itself: the human body and spirit. The limits set on this powerhouse provide further intrigue for its observers. One such limitation is that of linguistic competence and performance in relation to age. The emergence of the “critical age hypothesis,” also known as the critical period, set forth by neuropsychologist Eric Lenneberg in accordance with linguist Noam Chomsky’s belief that humans possessed the innate principles of language, labeled the fascination of the linguistic and psychological fields with the relationship of language development in reference to levels of sensory and social exposure or, in the case of this paper, the lack of such exposure (“Secret”).
The “critical age” is the time between birth and puberty in which children possess the ability to obtain a first language with all its “phonological, morphological, syntactic, and semantic rules” (Fromkin 62, 390). As testing this hypothesis is morally impossible, conclusions must be based on the observations of the development of deaf children born to hearing parents and feral children brought out of isolation. The accounts of feral, or wild, children mark some of the most intriguing studies for linguists and those in the field of language and psychological progression. Feral children are those that have “grown up in severe isolation with virtually no human contact” (“Secret”). The lack of exposure to language that many experience make observing them a prime basis for hypothesizing age inclination or limitations regarding native language development.
The most widely known and studied case of a feral child is Genie, who, when discovered in Los Angeles, California, in November of 1970, could not talk, walk, chew, or even straighten her arms and legs. For most of her thirteen-year-old life, she had been locked in a room and tied to a potty chair, receiving no human contact or interaction. When discovered, she was taken to Children’s Hospital in Los Angeles under the direction of multiple physicians, neurologists, psychologists, linguists, psycholinguists, and therapists. She was found to be at the developmental level of a one-year-old (Pines). Linguists found her to be the ideal subject: since she was past the predetermined critical age, could she entirely acquire a first language, and if not entirely, how much of a first language?
Over the next four years, Genie made slow, but steady, progress, in some ways similar to the development of normal children. The established phases of language acquisition are babbling at six months, the holophrastic stage in which the phonological system is developed through one-word, followed by two-word, “sentences,” which takes place at the end of the first year and into the second, and the telegraphic stage, in which strings of words that “lack function or grammatical morphemes” are used as the primary source of communication (Fromkin 390). Finally, between the ages of two and six years old, there is a “virtual language explosion,” in which stages are difficult to determine because the development of language is so swift (Fromkin 367). After seven months of intensive language therapy, Genie had acquired a large and varied vocabulary and was beginning to talk. She began with “one-word utterances…[t]hen…she began to string two words together on her own, not just while imitating what someone else had said” (Pines).
However, the telegraphic stage seemed to be the stopping point in Genie’s language development. Her progress was very slow: “a few weeks after normal children reach the two-word stage, their speech generally develops rapidly and explosively” (Pines), but Genie’s “two-word stage lasted for 4 months; negative sentences remained in the same state of development for nearly 3 years…[t]he great explosion [simply did] not occurred.”  Specifically, “Genie for the most part combined content words; an increase in sentence length largely consisted of an increase in the number of content words strung together and not of syntactic elaboration either by inclusion of grammatical markers or by an increase in hierarchal complexity.” The development, therefore, occurred semantically but not syntactically (Jones). In Genie’s case, a large signifier in the developmental abnormalities was the variety of words in her vocabulary. Susan Curtiss, a graduate student from UCLA who worked closely with Genie for over six years, “was struck with how different the words that she knew were from the vocabulary words that young children would know when they’re acquiring a first language” (“Secret”).    
Other feral children have been studied that seem, like Genie, to support the critical age hypothesis. Chelsea was born deaf and not exposed to language until she was thirty one. Like Genie, although she “received extensive language therapy and was able to acquire a large vocabulary,” she was unable “to develop a grammar” (Fromkin 53). Unlike Genie, however, whose sentences “sometimes seemed to have the structural complexity of a normal two-year-old’s,” Chelsea’s utterances “appeared to have no structure at all” (Birdsong 74). Isabelle was six years old when she was pulled from the closet in which she had been imprisoned with her deaf-mute mother. Retarded and speech-less, Isabelle was able to gain full use of language capacity and in two years “covered…the stages of learning that ordinarily required six” (Davis). Another young girl, Anna, after being discovered at the age of five, “learned to walk, talk in phrases and care for herself” within four years of treatment, after which she died. More progress might have been made had Anna more time to recover (Davis).
The success of Isabelle and hopeful progress of Anna, as well as the lack of success of Chelsea support Linneberg’s theory of an age at which language development meets a boundary. Because Genie was able to accumulate some linguistic competence to a certain point, an adaptation to the “critical age hypothesis” has been suggested. There is possibly a “’marginal’ time during which partial development is possible—what some researchers would refer to as a sensitive period” (Birdsong 74-5). This sensitive period is the category under which Genie falls: after the critical age, but still in the marginal time, which allowed her access to some measure of language. Chelsea, however, passed all critical and marginal periods, and therefore passed access to the development of a first language.
A study of Genie requires a study of the physical and neurological development she endured during her treatment. Curtiss suggested that, based on tests of dichotic listening, brain wave patterns, and Mooney Face Tests, Genie “seemed to use the right hemisphere of her brain for language.” Since the left hemisphere is the language center in normal brain structure, this unilateral hemispheric tendency would explain Genie’s unusual affinity for her highly visual vocabulary, a “special province of the right hemisphere.” Additionally, Curtiss theorized that
“the acquisition of language is what triggers the normal pattern of hemispheric specialization. Therefore, if language is not acquired at the appropriate time, ‘the cortical tissue normally committed for language and related abilities may functionally atrophy…[which] would mean that there are critical periods for the development of the left hemisphere. If such development fails, later learning may be limited to the right hemisphere” (Pines).
This hypothesis adeptly reasons Genie’s abnormal language development and suggests neurological reasoning as to the origin of the critical age tendency.
       With the emergence of new cases of isolated and feral children, as well as the development of technological advances in understanding human cognitive processes, such hypotheses as the critical and sensitive periods and lateralization of the right hemisphere in the absence of language development before puberty are becoming more familiar to researchers. As long as the human aspect remains a vital part of human interest cases, as in the instance of feral children, the existence of those interested in improving the life of such impoverished individuals will continue.

Work Cited

Birdsong, David, Ed. Second Language Acquisition and the Critical Period Hypothesis. Mahwah, NJ: Lawrence Erlbaum Associates, Inc., Publishers, 1999.

Davis, Kingsley. Human Society.

Fromkin, V., Rodman, R., & Hyams, N., An Introduction to Language. Boston: Heinle, 2003

Jones, Peter E. Contradictions and Unanswered Questions in the Genie Case: A Fresh Look at the Linguistic Evidence.

Pines, Maya. The Civilizing of Genie. Teaching English through the Disciplines: Psychology. Loretta F. Kasper, Ed., Whittier, 1997.

“Secret of the Wild Child.” NOVA. 7 Mar. 1997.


Aim of the tutorial

This tutorial will introduce the student to a famous case history: Genie. This is the story of a young girl who for the early part of her life was reared in a severly deprived environment. She became a test case for an important and controversial theory of language development - a biologically determined critical period for language acquisition. This tutorial will provide an opportunity to discuss normal language development, theories of language acquisition, the uniqueness of human language, and the ethics of psychological research.

What will happen:

Tutorial 6 Genie - Secret of the Wild Child

In this session we will watch a film about Genie. She was reared in extreme isolation, and was deprived of any social exposure to language. In the care of scientists she became an extrodinary case study in language development - does language have a critical period for language development?

A full transcript of this documentary is available

Tutorial 7 Genie Discussion

In tutorial 7 students will be given the opportunity to discuss Genie - Secret of the Wild Child. The film raises a wide range of issues. Topics for discussion may include:-

  • The ethics of research in psychology
  • What is normal language development?
  • How do we learn language?
  • Is language specific to humans?

These are only a few possible topics and you are encouraged to consider your own reactions to and questions about the film.

How do I prepare for this tutorial ?

Consult your course text for further information on language development, theories of language acquisition, and evidence for critical periods. You may also find some of these links useful:-


The Psychology Department's Website
This is the departmental web-site, it contains details on staff, research and other information including the Second Year Course

Get Gifs at