Sign language has a future in America that equates as a positive benefit for hearing children, newborns with hearing loss, hearing-native signers, and Deaf native-signers.
The cerebral organization for language is considered a higher cognitive function. Cognition and language skills begin in the language systems of the brain, “the hallmark specialization of the left hemisphere” (Neville et al., 1998). Interestingly, research has revealed that the right hemisphere is activated in the brains of native deaf signers and hearing native signers, known as Codas. Humphries writes, “the brain of a newborn is designed for early acquisition of language and cognition… Around five years of age, the plasticity of the brain begins to decrease” gradually" (Humphries et al., 2012).
Different areas of the brain’s complex language systems are activated in a normal-hearing individual and an average DHH individual. So what effects does sign language have on the brain, and could those effects be beneficial for everyone? Scientific research utilizing various testing methods and control groups revealed that sign language enhances cognition for hearing, hearing signers, and deaf native signers, young and old, regardless of biases, socioeconomic status, and stereotypes about sign language.
Could sign language instruction be beneficial to hearing children?
Researchers in Italy set out to examine that question. Testing methods used included (Capirci et al., 1998):
Corsi's block-tapping test, a test that measures spatial memory.
The Raven PM 47, a test that “measures visual perception and level of mental development. It consists of a series of increasingly complex matrixes, each missing one piece. The subject must select the correct piece to complete the matrix from six alternatives. For each trial, a single stimulus picture is presented above the six response-choice pictures. The subject’s task is to point to the one picture that fits the stimulus picture. There is no limit on time for responding. The correct solution for each problem requires logical nonverbal reasoning”.
Vocabulary comprehension tests, which are documented by the PPVT.
The participants in the research project were monolingual Italian-speaking families in a lower-middle-class neighborhood attending the same school. They had no experience or knowledge of the deaf culture or sign language. Fourteen young first-grade children volunteered to meet one hour a week with a Deaf teacher, while fourteen other classmates chose music or gymnastics. Over two years, the children were tested for their spatial memory with Corsi's block-tapping test, and for their visual-spatial cognition with the Raven PM 47 test.
The first test was administered before classes began, and at this point, all the students had similar results. Before summer vacation, the second testing of students was recorded. At this point, the students learning Italian Sign Language (ISL) showed higher test scores. When the children returned to begin second grade, the gap grew closer as the children who were not learning ISL had improved over the summer. However, the ISL students had maintained their performance level. The final test performed at the completion of second grade again resulted in higher performance for the ISL students. In addition to attaining higher scores, it was noted that the children had displayed a mutual understanding and respect for their Deaf teacher by always communicating with ISL. Respect for the Deaf Culture was generated through scaffolding.
Scaffolding is one's ability to guide and teach language, establishing cognitive development through interacting and socializing (Bailes et al., 2009). Parents do this intuitively with their children. The children learn to communicate by imitating their parents and family. Communication needs to be in a language, such as Italian, English, or sign language, for the language systems of the brain to be activated. This was emulated in Italy's first and second-grade ISL hours. The research team went a step further by implementing a second study (Capirci et al., 1998).
The next question the research team asked themselves was whether the reason for the improved test scores was merely due to the acquisition of a second language, or whether it was specifically due to sign language itself. A second test was made up of 49 hearing first-graders who were native Italian speakers. They were divided into 3 groups:
20 children who would learn Sign Language (the bimodal group).
20 children who would learn English (the bilingual group).
9 children who would not be learning any other language (the monolingual group).
The Corsi-block tapping test and the Raven PM47 were again used, with similar results. Those results affirmed that Sign Language improves visual-spatial cognition in young children from age 6 to 8.
Could sign language instruction be beneficial to hearing adults?
In 1998, PubMed Central Journal took a look at the biological aspects of sign language in how it activates various regions of the brain in adults. Specifically represented are the organization of language systems of the left and right hemispheres. Neville and his team of scientists sought to understand how highly special neurological language systems develop, the degree of biological constraint, and “the extent to which they depend on and can be modified by input from the environment” (Neville et al., 1998).
Neville and his team of scientists used three groups of healthy adults from a mean age of 27:
Normal-hearing adults who spoke English and had no American Sign Language (ASL) experience.
Congenitally, genetically deaf adults who had later learned English.
Normal hearing, bilingual individuals born to deaf parents who knew ASL and English
Neville and his team used functional magnetic resonance imaging (fMRI), which provides a visual image of language activation in the various regions of the left and right hemispheres. Using fMRIs, the team analyzed the brain activity of these groups when exposed to different experiences of language, including ASL. The results provided a vivid picture of the difference in brain activity between the three groups. While many brain areas were activated, the primary difference was over the right and left hemisphere activations.
The left hemisphere of hearing subjects was activated while they were reading English silently. This agreed with other studies of brain activity in language processing and memory. The deaf subjects revealed little left hemisphere activation and notably increased right hemisphere activation. The hearing native signers’ left hemispheres matched portions of the hearing non-signers with no right hemisphere activity.
During exposure to ASL, the pattern of activation of normal-hearing adults showed no change in right or left hemisphere activity. Congenitally, genetically deaf adults who had later learned English displayed left and increased right hemisphere activation. Normal hearing, bilingual individuals born to deaf parents who knew ASL and English had enhanced left and right hemisphere activity, while the right hemisphere was not quite as robust as that of the deaf signer.
So what effects does sign language have on the brain, and could those effects be beneficial for everyone?
Cerebral organization for language begins in the language system of the brain, and is "the hallmark specialization of the left hemisphere." The right hemisphere is activated in the brains of native deaf signers and Codas.
Research in Italy documents the enhanced cognitive functions of hearing children who learned sign language over their peers who did not learn the visual-spatial language. Age of language acquisition, family, and community biases are all important factors affecting the development of language cognition of every individual. Sign language has a future in America that equates to a positive benefit for hearing children, deaf newborns, hearing native signers, and Deaf native signers.
Scientific research has provided proof that sign language enhances brain function. Learning Sign Language activates regions of the brain for spatial memory, visual perception, mental development, logical nonverbal reasoning, and visual-spatial comprehension. Hearing individuals with no knowledge of sign language do not use the right hemisphere of the complex language systems within the brain. Hearing children taught sign language at a young age outperformed monolingual and bilingual peers. Economic status or social environment are not the determining factors in the organization of the brain's biological ability.
The benefits of teaching sign language to all children in every school warrant the activation of more research and new programs.
References
Bailes et al. (2009). Language and Literacy Acquisition through Parental Mediation in American Sign Language. Sign Language Studies (9) 417-456
Capirci et al. (1998). Teaching Sign Language to Hearing Children as a Possible Factor in Cognitive Enhancement. Journal of Deaf Studies and Deaf Education (3) 135-42
Humphries et al. (2012) Language acquisition for deaf children: Reducing the harms of zero tolerance to the use of alternative approaches. Harm Reduction Journal (9) 16
Neville et al. (1998). Cerebral organization for language in deaf and hearing subjects: Biological constraints and effects of experience. PNAS (3) 922-929
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