Beyond Pragmatics. Morphosyntactic Development in Autism.pdf

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J Autism Dev Disord initiate interactions. Marginally significant group differences suggested that adults interacting with children in the autism group produced more expansions of their own utterances, and fewer replies to the children’s utterances. Adults may have been less likely to reply to children who produced more uninterpretable utterances, jargon, and echolalia. Overall, the adult discourse analysis suggests that adults interacted similarly with children across groups, to the extent that we were able to measure differences. One limitation of the present findings draws on the dichotomy between competence and performance. An individual’s speech at any given moment (performance) may not be an accurate index of underlying knowledge (competence) of the syntax of the language (Chomsky, 1957). The presence of speech errors in everyday speech (e.g., ‘‘a five pile car up’’) does not suggest that people have not mastered their syntax, but rather that there is ‘‘slippage’’ or noise in the process of producing an utterance. This raises the possibility that children with autism may have a greater underlying competence, or knowledge of the syntactic structures of English, but that they are less able or less willing (e.g., because of deficits in social reciprocity) to access this knowledge in some contexts. For example, they could be less comfortable with a relatively unfamiliar experimenter, and thus be less likely to produce syntactically complex structures. In support of this hypothesis, children with autism performed as well as controls on a measure (the PPVT-III) that required non-verbal rather than spoken responses. By including other standardized measures of syntactic skills, it would have been possible to directly address this concern; however, to our knowledge, no standardized measures are appropriate for assessing syntax at this very early stage of language acquisition. The CELF-Preschool, for example, which targets children ages 3–6, is often too difficult for children with autism of this age (e.g., Kjelgaard & Targer-Flusberg, 2001). There are, however, several sources of evidence against the ‘‘performance deficit’’ as the sole explanation for syntactic delays in the autism group. First, children performed another non-verbal language task (not described here, Eigsti & Bennetto, 2001), and the autism group exhibited specific syntactic impairments on that task. Second, the children with autism were equally as talkative as their peers, and talked about similar topics. A third argument comes from the broader language acquisition literature. Seidenberg and MacDonald (1999) have suggested a performance-based alternative to Chomsky’s generative approach. In their probabilistic framework, language production and acquisition emerge as learners and talkers exploit multiple probabilistic constraints drawn from both linguistic and nonlinguistic information. Under this framework, production data observed in the course of language acquisition are informative about how children extract the underlying regularities of the language system. This approach suggests that the less complex syntax observed in language of children with autism may reflect actual delays in their knowledge, rather than ‘‘performance factors.’’ The present data, which were collected from a single play session, present a further limitation. The children with autism were somewhat acclimated to the examiner and the physical environment of the play-room, because the play session was recorded during their second visit to the lab. Nonetheless, children with autism may have greater difficulty adjusting to this still relatively novel situation. This play session may have thus elicited somewhat less complex or typical spontaneous language from this group of children. Future studies may address this concern by performing a more extended familiarization procedure or, alternatively, by documenting children’s speech and language in the home setting, where they are likely to be most comfortable. One issue that must be raised in considering how generalizable the study’s findings may be is whether the participants are characteristic of the autism population. The ASD group was comprised solely of high-functioning children with autism, not other diagnoses such as PDD/NOS or Asperger syndrome. The children all had a history of language delay, as is characteristic of autism, but were all verbal at the time of the study; inclusion criteria required that participants have at least 2-word phrases in their speech at home. Certainly, given the wide spectrum of abilities in autism, it may be the case that the syntactic deficits identified here may be less apparent in a sample of children with diagnoses other than classic autism, or in a sample of children with a wider range of developmental abilities. In addition, some research suggests the presence of several distinct subtypes of children with ASD, where one subgroup has deficits that parallel those observed in children with specific language impairment (SLI), whereas other subgroups exhibit few morphosyntactic delays (Kjelgaard & Tager-Flusberg, 2001). Analyses examining the possibility that participants in the autism group could be best characterized by normal and language-impaired subgroups were not consistent with these previous findings. Instead, the data indicated a rather consistent morphosyntactic deficit 123
J Autism Dev Disord across participants with autism, independent of functional level, consistent with least one large study of language profiles in autism (Jarrold et al., 1997). Furthermore, the focus in this study was on identifying deficits that characterized children with autism as a group, and, due to the labor-intensive language analyses employed, numbers of participants were insufficient to conclusively determine the presence of coherent subgroups. Further study is needed to address these issues. Finally, the present study shares a limitation with much of the research on language in autism: the challenge of choosing appropriate matching criteria. Matching on the PPVT-III raises a concern that the identification of objects in a PPVT-style task may be a peak of ability in high functioning individuals on the autism spectrum, that serves to over-estimate IQ (Mottron, 2004). In this study, non-verbal IQ served as the primary matching criterion, and groups were also matched on PPVT-III receptive vocabulary to maintain consistency with the large literature also matching on that basis. In addition, only participants who were combining words into 2-word phrases were included, in order to insure that all participants had at least begun to communicate verbally. To address this limitation in the matching procedure, analyses were performed both with and without the PPVT-III results covaried , with no change in results. The major finding of the present study is that children with autism, compared with chronological age- (DD group) and non-verbal mental age- (DD and TD groups) matched peers exhibited clear delays in syntactic knowledge. In contrast to these syntactic impairments, the autism group’s lexical knowledge was unimpaired. We have discussed some possible factors underlying these syntactic impairments, including the production of jargon, the discussion of less complex events in the world, and the atypical sequence of learning of syntactic structures. One important implication is that receptive vocabulary abilities, such as those measured by the PPVT-III, are likely an inadequate marker of ‘‘language ability,’’ and studies that match groups based only on lexical measures are likely to overestimate the comprehension of children in the autism group. Acknowledgement This research was supported by the NIMH (R03 grant # MH61032-01), a Young Investigator award from the Journal of Language Learning, and a Dissertation Award from the Society for Science of Clinical Psychology, to IME. We are especially grateful to the parents and children that participated in the study. Appendix Index of Productive Syntax (IPSyn) Items Table 7 Verb phrases subscale Sentence structures subscale Verb Two-word combination Particle or preposition Subject-verb sequence Prepositional phrase Verb-object sequence (Preposition + NP) Copula linking two nominals Subject-verb-object sequence Catenative (pseudo-auxiliary) Conjunction (any) preceding a verb Auxiliary be, do, have in VP Sentence with two VPs Progressive Suffix Conjoined phrases Adverb Infinitive marked with to Modal preceding verb Let/Make/Help/Watch introducer Third person singular present Adverbial conjunction tense suffix Past tense modal Propositional complement Regular past tense suffix Conjoined sentences Past tense auxiliary Wh- clause Medial adverb Bitransitive predicate Copula, modal, or auxiliary Sentence with 3 or for emphasis or ellipsis more VP’s (non-contractible context) Past tense copula Relative clause, marked or unmarked Bound morpheme on verb Infinitive clause with or on adjective new subject Gerund Fronted, center-embedded subord. clause Passive construction Question-Negation Subscale Noun Phrases Subscale Intonationally marked question Proper, mass, or count noun Routine do/go, existence Pronoun or prolocative question, wh- pronoun (not modifier) Negation (no(t), can’t, don’t) + Modifier (adjective, X (NP, VP, PP) possessive, quantifier Initial wh- pronoun followed 2-word NP: Article/ by verb modifier + nominal Negative morpheme between Article, used before a noun subject and verb Wh- question- inverted modal, Two-word NP after verb copula, auxiliary or preposition Negation of copula, modal, Plural suffix or auxiliary Yes/no question- inverted modal, 2-word NP (as N4) copula, auxiliary before verb Why, When, Which, Whose 3-word NP (Determiner + Modifier + Noun) Tag question Adverb modifying adjective or nominal Questions with negation + Any bound morpheme on inverted copula, modal noun, adjective Note: NP = noun phrase, VP = verb phrase, PP = prepositional phrase 123
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