Semantic and pragmatic language development in typical acquisition, autism spectrum disorders, and Williams syndrome with reference to developmental neurogenetics of the latter

The elucidation of the biological bases of a complex trait like human language proceeds from identification of precise behavioral phenotypes to investigation of the underlying genes. The human behavioral parts of this dissertation focus on understanding the reasons for children's overuse of definite article 'the', to refer to one of several objects in a context set, as opposed to the unique established referent. Competing theories argue the deficit is either in children's semantic computational knowledge (of uniqueness/maximality), or in their pragmatic/social awareness/theory-of-mind development. Experiments in this dissertation focused on children's comprehension and interpretation of the indefinite and definite determiners, as well as 'that', anaphors 'another' and 'same', and free relative clauses. The results in this thesis suggest that in typically developing (TD) children the late acquisition of determiner 'the' is due to the late maturation of the semantic principle of maximality. Children with autism spectrum disorders (ASD) and with Williams syndrome (WS) either manifested an adult-like competence, an absence of manifestation of knowledge, or a pattern found in TD younger children (where 'that' is understood better than 'the' as referring to the salient unique referent) -- indicating delay of development of the language faculty, but no deviance. This suggests that the observed deficits in ASD and WS pattern with those in TD, and hence are also semantic in nature. The mouse neurogenetic part of this dissertation investigates whether the GTF2I family of genes, causal to WS behavioral phenotype, also contributes to WS cortical development.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Brain and Cognitive Sciences.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2009

Author dc:creator

• Modyanova, Nadezhda N

Advisor dc:contributor.advisor

• Kenneth N. Wexler.

• Brain and Cognitive Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/57547

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/57547