The Deaf, Sign Language, and Spatial Cognition
Jennifer Milner
March 22, 2002

The deaf present a unique challenge to educational systems. The inability of deaf children to hear leads to potential deficiencies and delays in their learning in a typical classroom setting. Comprehension of spoken language presents an obvious hurdle to the deaf student. In an oral-only classroom, they understand less than half of all utterances made by the teacher (Schirmer 2001). Deaf students also have a harder time learning to read and write because of their inability to connect spoken and written language (Bellugi, Tzeng, Klima, and Folk, 1989). Such delays in comprehension and literacy often lead to delays in math and science because of the inability of curriculum created for hearing students to bridge the gaps in language that the deaf often experience (Nunes and Moreno, 2002; Yore, 2000). While there are numerous potential weaknesses for deaf learners, they can develop certain advantages. Many of the deaf use sign language as their primary form of communication.* The unique traits of sign language provide the deaf with potential benefits which can be used to improve their learning.

*In this paper, sign language refers to natural sign systems which have developed naturally among the deaf and not artificial sign systems that have been created outside of deaf communities to mimic spoken languages. American Sign Language is one such example of a natural sign system; these sign systems tend to be preferred forms of communication among the deaf (Meyer and Akamatsu, 1999).

Understanding Sign as a Visuo-Spatial Language

Until fairly recently, American Sign Language and other forms of sign language were not thought to be language at all. They were considered pidgin forms of spoken languages that lacked grammar and didn't facilitate abstract thinking (Sacks, 1990). This view has changed, and studies have revealed that sign languages might even have unique benefits that aren't provided by the use of spoken language.

Sign is visuo-spatial, meaning that it makes "structured use of space at all linguistic levels. Many syntactic functions fulfilled in spoken languages by word order or case marking are expressed in [American Sign Language] by spatial mechanisms." Communicating in sign requires that signers use spatial cues and allows them to incorporate a theater of space around their body to convey messages. Despite this added level of spatial perception and memory, deaf children learn sign language at the same pace that hearing children learn spoken language even with having to "acquire non-language spatial capacities that are prerequisites to the linguistic use of space" (Bellugi, Tzeng, Klima, and Folk, 1989). This additional level of development has been shown to have repercussions on the development spatial cognition for these native signers.

Sign Language in the Brain

In most adults, analytical tasks like understanding spoken language occur in the left hemisphere of the brain while the right hemisphere is where processing of non-language perception takes place. For these reasons, it was once uncertain where sign language processing would occur. While sign language has a lexical and grammatical structure like spoken language, it relies on visual and spatial processing to be understood (Sacks, 1990).

Studies of native deaf signers who have suffered an injury to one hemisphere or the other of their brain have shown that sign language is understood primarily in the left temporal lobe despite its spatial organization. Research by Helen Neville and Ursula Bellugi found that deaf signers with damage to their right hemisphere distort the spatial layout of sign language while those with damage to their left hemisphere often suffer a complete breakdown in the use of sign. In addition to confirming that sign functions as a language in the brain, this also indicates that the brain has the potential to represent a completely different kind of space than the usual topographical space (Neville and Bellugi, 1978).

Further study by Neville has made use of functional magnetic resonance imaging (fMRI) to compare language processing between the hearing and the deaf. Both hearing and deaf subjects use classical anterior and posterior language areas within the left hemisphere when recognizing their native language, English or American Sign Language respectively. However, activity is also observed in right hemisphere prefrontal regions and posterior and anterior parts of the superior temporal sulcus when native signers, both deaf and hearing, recognize and process sentences in sign. These findings imply that the specific nature and structure of ASL results in employing the right hemisphere in processing language. This "[activity] within the right hemisphere may be specifically linked to the linguistic use of space" (Corina, 2002).

These studies indicate that the inferior frontal and posterior temporal parietal regions of the left hemisphere are ideally suited to the processing of natural languague whether that language is oral or visuo-spatial. However, it is also apparent that activity is occurring in the brain of native deaf users of sign, and also in native hearing signers, that is not happening in the hearing brain of non-signers. This leads to differences in abilities between signers and non-signers, specifically differences in spatial cognition.

The Differences in Spatial Cognition Between Deaf and Hearing Children

In order to better understand how using sign language effects spatial cognition, Ursula Bellugi compared the abilities of deaf children using Chinese Sign Language and hearing children. In particular, she focused on the ability to use spatial analysis to understand dynamic displays. To test this, "sixty nonsense Chinese characters were presented [individually] as rapidly moving patterns of light" to the children with instructions to "watch each point-light display and write down the character underlying the continuous flow of movement." The deaf children were able to apply their enhanced spatial capacities to this task and were consequently far better at "[distinguishing] between the movements representing strokes and transitional movements" and "[remembering] the sequence and spatial arrangements" (Bellugi, Tzeng, Klima, and Folk, 1989).

The same tests were also administered to adults in the United States with comparable results: "Again the deaf subjects were significantly better than the hearing … [suggesting] that the enhancement of spatial abilities seen in deaf children may have a lasting effect into adulthood" (Bellugi, O'Grady, Lillio-Martin, Hynes, Van Hoeck, and Corina, 1989). In addition to these tests, numerous other spatial tests have been used to compare the abilities of deaf and hearing children including copying geometric shapes, spatial construction, spatial organization, and facial discrimination.

While the largest advantage seems to occur with recognizing and interpreting dynamic displays like the nonsense characters, the deaf subjects have also shown a consistent advantage on facial discrimination and spatial construction. In some of cases, "these younger deaf childen [ages 3 to 5] were scoring as high as hearing 6 year-olds" (Bellugi, O'Grady, Lillio-Martin, Hynes, Van Hoeck, and Corina, 1989). One particularly interesting case is that of facial discrimination. In one study, children matched images of a face from the front with views from differing perspectives and under varying amounts of light. Deaf children performed better than hearing children on these tests. While the use of spatial cognition is partially attributed to these increased ability to recognize faces in different situations, this difference is also affected by the "important role that facial expression plays in [American Sign Language] grammar" (Bellugi, O'Grady, Lillio-Martin, Hynes, Van Hoeck, and Corina, 1989).

These results help to pinpoint the spatial skills learned in acquiring sign language. The question remains as to how these skills can be used to increase academic performance and understanding of deaf learners.

Effects on Learning

Perhaps most importantly, spatial abilities give one a better sense of their surroundings. Children and adults with a heightened spatial ability are better able to safely move through their physical environment. (Nilges and Usnick, 2000) This is obviously an important skill for deaf children who don't have the advantage of hearing potential obstacles or dangers.

Spatial abilities also help children to better understand math. The National Council of Teachers of Mathematics identifies these abilities as an important perquisite to understanding geometry: "Children who develop a strong sense of spatial relationships and who master the concepts and language of geometry are better prepared to learn number and measurement ideas, as well as other advanced mathematical topics" (NCTM, 2002).

While enhanced spatial abilities have been shown to improve performance in mathematics, deaf children often don't do as well as hearing children in this area. Research has found that incorporating spatial skills into the mathematics education can improve the performance of deaf children. For instance, a software program implemented in several schools in London that incorporates visual and spatial processing into typical math problems was found to help deaf children better understand the underlying concepts (Nunes and Moreno, 2002). Multidisciplinary approaches connecting physical education and mathematics might also increase spatial ability because "the selection, processing, and organization of spatial information are critical for success in each discipline" (Nilges and Usnick, 2000). Similar programs are also being developed in other disciplines like science.Such additions to curriculum and could give deaf children a chance to use their spatial abilities to overcome academic hurdles and could also offer hearing children chances to improve their spatial cognition.

References

Bellugi,U.; Tzeng, O.; Klima, E.; and Folk, A. (1989). "Dyslexia: Perspectives From Sign and Script." Reading to Neurons, ed. A. Galaburda. Cambridge: MIT Press.

Bellugi, U.; O'Grady, L.; Lillio-Martin, D.; O'Grady Hynes, M.; Van Hoek, K.; and Corina, D. (1989). "Enhancement of Spatial Cognition in Deaf Children." Gesture to Language in Hearing Children, ed. V. Volterra and C. Erting. New York: Springer Verlag.

Cawthon, S. (2001) "Teaching Strategies in Inclusive Classrooms With Deaf Students." Journal of Deaf Studies and Deaf Education, 6:3, 212-225.

Corina, D. "Sign Language and the Brain." <http://www2.rz.hu-berlin.de/linguistik/institut/syntax/writing/signbrain.htm> 19 March 2002.

Mayer, C. and Akamatsu, C. (1999). "Bilingual-Bicultural Models of Literacy Education for Deaf Students: Considering the Claims." Australian Journal of Education of the Deaf, 2, 5-9.

The National Council of Teachers of Mathematics. "1989 NCTM Standards." <http://www.nctm.org> 9 March 2002.

Neville, H. and Bellugi, U. (1978). "Patterns of Cerebral Specialization in Congenitally Deaf Adults: A Preliminary Report." Understanding Language Through Sign Language Research, ed. P. Siple. New York: Academic Press.

Nilges, L. and Usnick, V. (2000). "The Role of Spatial Ability in Physical Education and Mathematics." Journal of Physical Education, Recreation, and Dance.

Nunes, T. and Moreno, C. (2002). "An Intervention Program for Promoting Deaf Pupils' Achievement in Mathematics." Journal of Deaf Studies and Deaf Education, 7:2, 120-133.

Sacks, O. (1990). Seeing Voices: A Journey into the World of the Deaf. New York: Harper Perennial.

Yore, L. (2000). "Enhancing Science Literacy for All Students With Embedded Reading Instruction and Writing-to-Learn Activities." Journal of Deaf Studies and Deaf Education, 5:1, 105-122.