Why is psycholinguistics studied?

This page will be looking and the horrific case of Genie, a young girl from Arcadia, California, whose extreme and saddening case of social deprivation and contact with language can shed some light on some of the mysteries of psycholinguistics. 

Genie, which was a pseudonym for the girl for legal reasons, was a victim of severe social isolation for most of the first thirteen years of her life. She had been locked inside her bedroom and strapped to a potty chair during the days, and slept in a caged crib, confined by a straight jacket by night. To further make Genie’s situation worse, her father would not allow her brother, the one tasked with feeding her infant food, to speak to her, and he himself would make growling dog like noises from behind the door to keep her quiet, and when she did try to vocalize she would be beaten by her father. When she was found, at the age of 13, she had learnt from the beatings she received to suppress almost all vocalizations, she could speak very few words, and the ones she could tended to be negative, such as "stop it".
 
Victim Of Domestic ViolenceStop Hand Gesture
 
Due to Genie’s extreme and horrific circumstances, she was of great interest to psychologists, linguists and neurologists who looked at her case, and could see the atypical development of her mind, and thus of her language. This was an exceptional circumstance as this would never be able to be recreated in an experimental way due to the awful nature of Genie's treatment. Harlan Lane, who was a psychologist at Northeastern University said that “It’s a terribly important case. Since our morality doesn’t allow us to conduct depriva­tion experiments with human beings, these unfortunate people are all we have to go on.”
 
In her case study, Susan Curtiss (1977) noted that many efforts were made in an attempt to teach Genie language but she never fully acquired linguistic competence. As such, Genie's case lends strength to the argument that there is a "critical period" in a child's development which, after has been missed, language will never be able to be fully acquired; a theory which was first proposed by Eric Lennenberg. Curtiss also went on to develop a controversial hypothesis about how language learning affects the two hemispheres of the brain, and Genie has also stirred up debate about between language and other mental abilities.
 
There have been other cases such as Genie's. Anna, who was looked at by Davis (1940, 1947) who was a girl of around five years of age that had been found tied to a chair in a storage room of her farm home and had apparently been there since babyhood. When found, she too was unable to talk, and when relocated to a children's home, lay in a limp position, completely expressionless and was believed to be potentially deaf and blind. However, after nine months she was moved to a foster home and she began to make improvements both cognitive and motor, after her foster mother gave her "unremitting attention". After she left the foster home, and shortly before her death, she was located in a home for retarded children, and began to develop speech after living there for two years. This is possibly further evidence of the critical period, as it took her so long to develop one word speech, a level which she should have developed much quicker had she had a typical upbringing.
 
In Language Development in Exceptional Circumstances [2] it is noted on page 115 that Luria (1973) suggested that the brain develops differently if "one sensory modality is absent. As such, this means that in Genie's case, due to lack of communication, her auditory sense was under stimulated, and as such her brain would have atypically developed. This also links to more information on why psycholinguistics: What is psycholinguistics? - Atypical language development
 
Language Development in Exceptional Circumstances also outlines why it may be that children that have been in these cases of social isolation have underdeveloped in the way they have. For example, it suggests malnutrition could be a cause, but this alone has not been. However, it also says that John Dobbings (1984) commented how malnutrition may produce "irreversible deficits and distortions... in the growing brain." Other theorists also suggest that these cases show auditory-verbal stimulation and lack of opportunities for play can affect the development of the brain. Although it is impossible to say exactly WHICH have contributed and how much to cases like Genie's, it would seem that they are fundamental to the brain's development, and lack of them results in the saddening differences we see in these cases.

References

[1] Bishop, D., (1993). Language Development in Exceptional Circumstances. 
[2] Curtiss, S., (1977). Genie: A Psycholinguistic Study of a Modern Day Wild Child.