Edward S. Klima

Is there a social module? language, face processing, and theory of mind in individuals with williams syndrome

Many species can respond to the behavior of their conspecifics. Human children, and perhaps some nonhuman primates, also have the capacity to respond to the mental states of their conspecifics, i.e., they have a theory of mind. On the basis of previous research on the theory-of-mind impairment in people with autism, together with animal models of intentionality, Brothers and Ring (1992) postulated a broad cognitive module whose function is to build representations of other individuals. We evaluate the details of this hypothesis through a series of experiments on language, face processing, and theory of mind carried out with subjects with Williams syndrome, a rare genetic neurodevelopmental disorder resulting in an uneven lin-guisticocognitive profile. The results are discussed in terms of how the comparison of different phenotypes (e.g., Williams syndrome, Down syndrome, autism, and hydrocephaly with associated myelomeningocele) can contribute both to understanding the neuropsychology of social cognition and to current thinking about the purported modularity of the brain.

Remembering in signs

Abstract In a short-term memory experiment, signs of American Sign Language in list lengths of three to seven items were presented to deaf college students whose native language is American Sign Language. A comparable short-term memory experiment for words (words representing the English translation-equivalents of the signs) was presented to hearing college students. Recall was written, immediate and ordered. Overall, short-term memory mechanisms in the deaf seem to parallel those found in hearing subjects, even with the modality change. A significant number of multiple intrusion errors made by deaf subjects to signs were based on formational properties of the signs themselves, a result paralleling the phonologically based errors in experiments with hearing subjects. Our results are consistent with a theory that the signs of American Sign Language are actually coded by the deaf in terms of simultaneous formational parameters such as Hand Configuration, Place of Articulation and Movement. Evidence is given that signs are treated by the deaf as consisting of independent parameters — specific to American Sign Language — which are essentially arbitrary in terms of meaning.

Once more with feeling: Affect and language in atypical populations

The study of clearly identifiable patterns of atypical development can inform normal development in significant ways. Delayed or deviant development puts in high relief not only the sequence of development but also the individual components. This article presents the results of studies that compare adolescents with Williams syndrome, a rare metabolic neurodevelopmental disorder resulting in mental retardation, with cognitively matched adolescents with Down syndrome. We investigate the interaction between affect and language through storytelling. In contrast to the adolescents with Down syndrome, the Williams syndrome subjects tell coherent and complex narratives that make extensive use of affective prosody. Furthermore, stories from the Williams but not the Down subjects are infused with lexically encoded narrative evaluative devices that enrich the referential content of the stories. This contrast in expressivity between two matched atypical groups provides an unusual perspective on the underlying structure of the social cognitive domain.

Language, modality and the brain

Studies of the signed languages of deaf people have shown that fully expressive languages can arise, outside of the mainstream of spoken languages, that exhibit the complexities of linguistic organization found in all spoken languages. Thus, the human capacity for language is not linked to some privileged cognitive-auditory connection. However, the formal properties of languages (spoken or signed) appear to be highly conditioned by the modalities involved in their perception and production. Multi-layering of linguistic elements and the use of space in the service of syntax appear to be modality-determined aspects of signed languages. Analyses of patterns of breakdown of signed languages provide new perspectives on the nature of cerebral organization for language. The studies reviewed in this article show that the left cerebral hemisphere in man is specialized for signed as well as spoken languages, and thus may have an innate predisposition for language, independent of language modality.

The relationship between age and IQ in adults with Williams syndrome.

The relationship between age and IQ was evaluated in a cross-sectional sample of 80 individuals with Williams syndrome (17 to 52 years). The relationship between age and WAIS-R subtest scores was such that increases and decreases in raw scores occurred at a rate sufficient to maintain stability of age-corrected scaled scores, indicating a developmental trajectory similar to that of the WAIS-R normative sample. Despite stability of age- corrected scaled scores with age, increased age was related to higher Performance IQ. This disparity, which occurs during the conversion of sums of scaled scores to IQs, may be unique to the WAIS-R. Although Performance IQ increased with age, results imply that the overall IQ of an adult with Williams syndrome will likely remain stable.

TWO FACES OF SIGN: ICONIC AND ABSTRACT*

In this paper, we show that the total range of the communication system of the deaf is considerably enriched but at the same time rendered more difficult to analyze, because pantomime and other spontaneous nonsign representations occur in the same mode as regular ASL signs in deaf discourse. We note that the rarification of what was originally nonsign depiction is clearly an important source of regular ASL signs. We show that criteria can be established that would distinguish the clear cases of pantomime from the regular ASL signs. Nonetheless, there remain a sizable number of regular ASL signs which, although they are neither pantomimic nor otherwise freely mimetic, still appear to retain an iconic cast. We show that very few ASL signs are actually transparent; that is, a nonsigner cannot guess the meaning of a sign in the absence of further information. On the other hand, many signs are iconic in the sence that nonsigners, when given the sign and its meaning, show considerable agreement in how the two are related. More important in terms of language and its users is the significance of iconicity for deaf signers themselves. This paper shows that while in special circumstances the deaf do play on iconic elements of certain signs for special effects, iconicity plays no observable role in the coding of signs in short-term memory. The abstract formational parameters definitely dominate. We further note that it is the abstract system and not purely iconic aspects that have determined observed historical changes in the form of ASL signs. We interpret this as indicating the deeper structural significance of the abstract formational level. Finally, we show that very widespread and productive grammatical processes, especially suited for a visual-gestural language, override the iconic aspects of signs also at the synchronic structural level.

The neural organization of language: evidence from sign language aphasia

To what extent is the neural organization of language dependent on factors specific to the modalities in which language is perceived and through which it is produced? That is, is the left-hemisphere dominance for language a function of a linguistic specialization or a function of some domain-general specialization(s), such as temporal processing or motor planning? Investigations of the neurobiology of signed language can help answer these questions. As with spoken languages, signed languages of the deaf display complex grammatical structure but are perceived and produced via radically different modalities. Thus, by mapping out the neurological similarities and differences between signed and spoken language, it is possible to identify modality-specific contributions to brain organization for language. Research to date has shown a significant degree of similarity in the neurobiology of signed and spoken languages, suggesting that the neural organization of language is largely modality-independent.

Role of the left hemisphere in sign language comprehension

We investigated the relative role of the left versus right hemisphere in the comprehension of American Sign Language (ASL). Nineteen lifelong signers with unilateral brain lesions [11 left hemisphere damaged (LHD) and 8 right hemisphere damaged (RHD)] performed three tasks, an isolated single-sign comprehension task, a sentence-level comprehension task involving simple one-step commands, and a sentence-level comprehension task involving more complex multiclause/multistep commands. Eighteen of the participants were deaf, one RHD subject was hearing and bilingual (ASL and English). Performance was examined in relation to two factors: whether the lesion was in the right or left hemisphere and whether the temporal lobe was involved. The LHD group performed significantly worse than the RHD group on all three tasks, confirming left hemisphere dominance for sign language comprehension. The group with left temporal lobe involvement was significantly impaired on all tasks, whereas each of the other three groups performed at better than 95% correct on the single sign and simple sentence comprehension tasks, with performance falling off only on the complex sentence comprehension items. A comparison with previously published data suggests that the degree of difficulty exhibited by the deaf RHD group on the complex sentences is comparable to that observed in hearing RHD subjects. Based on these findings we hypothesize (i) that deaf and hearing individuals have a similar degree of lateralization of language comprehension processes and (ii) that language comprehension depends primarily on the integrity of the left temporal lobe.

Williams syndrome: an exploration of neurocognitive and genetic features

Abstract We report here on significant attempts to forge links between neurodevelopmental disorders, development of specific neuropsychological abilities, and the functional establishment of patterns of brain organization. Such research programs are providing converging evidence for the coherence or dissociability of components of cognition (e.g. language, spatial cognition) and will allow development of theoretical explanations for the underlying architecture of human cognition. Williams syndrome involves focal rather than generalized cognitive deficits, and offers an important opportunity for linking brain findings to specific atypical cognitive profiles. The unusual neurocognitive profile of Williams syndrome makes it a compelling model of the pathways between genes and human cognition. It is becoming clear that the syndromes unique genomic organization may also make it an important model of human chromosomal evolution and disease. These studies with a specific neurodevelopmental disorder that presents a rare dissociation of higher cortical functioning may provide opportunities to explore some of the central issues of cognitive neuroscience that tie cognitive functions to brain organization and ultimately to the human genome.

Discourse Deficits Following Right Hemisphere Damage in Deaf Signers

Previous findings have demonstrated that hemispheric organization in deaf users of American Sign Language (ASL) parallels that of the hearing population, with the left hemisphere showing dominance for grammatical linguistic functions and the right hemisphere showing specialization for non-linguistic spatial functions. The present study addresses two further questions: first, do extra-grammatical discourse functions in deaf signers show the same right-hemisphere dominance observed for discourse functions in hearing subjects; and second, do discourse functions in ASL that employ spatial relations depend upon more general intact spatial cognitive abilities? We report findings from two right-hemisphere damaged deaf signers, both of whom show disruption of discourse functions in absence of any disruption of grammatical functions. The exact nature of the disruption differs for the two subjects, however. Subject AR shows difficulty in maintaining topical coherence, while SJ shows difficulty in employing spatial discourse devices. Further, the two subjects are equally impaired on non-linguistic spatial tasks, indicating that spared spatial discourse functions can occur even when more general spatial cognition is disrupted. We conclude that, as in the hearing population, discourse functions involve the right hemisphere; that distinct discourse functions can be dissociated from one another in ASL; and that brain organization for linguistic spatial devices is driven by its functional role in language processing, rather than by its surface, spatial characteristics.