Acquisition Of Logical Words In Mandarin-Speaking Typically Developing Children And Children With Autism Spectrum Disorders

Objective:To investigate how typically-developing children and high-functioning children with autism spectrum disorders interpret logical words in Mandarin Chinese and to explore the possible acquisition processes in each group.(1) For typically-developing children, we take a cross-linguistic perspective to investigate whether preschool Mandarin-speaking children resemble their English-speaking peers and acquire logical words according to their counterparts in classical logic at the initial stage of language acquisition, i.e., to test the theoretical hypothesis of "logical nativism"(Crain2012).(2) For children with autism spectrum disorders, we take a developmental perspective to assess4-15-year-old Mandarin-speaking high-functioning children with autism spectrum disorders on their knowledge of the semantics and pragmatics of logical words, and to compare whether this knowledge differs from typically-developing children.Methods:(1) To investigate acquisition of logical words in Mandarin-speaking preschool children, we adopted the primary methodo-logy of Truth Value Judgment task (Crain&Thornton1998) and tested a total group of116Mandarin-speaking children (aged3;11to6;0) on their interpretation of logical words including the disjunction word "huozhe"(English:or) and the universal quantifier "mei"(English: every). Children participated in five experiments, with the first two measuring their semantic knowledge and the last three assessing their pragmatic knowledge of logical words. Specifically, Experiment1evaluated Mandarin-speaking children’s semantic knowledge of an asymmetric universal related with the interpretation of disjunction in sentences with the universal quantifier. Experiment2, for the first time, investigated children’s knowledge of this semantic universal in double object constructions. Experiment3tested children’s knowledge of the pragmatic phenomenon of scalar implicatures, as well as whether children were sensitive to the semantic constraint for the computation of scalar implicatures. Experiment4further assessed whether young children computed scalar implicatures related to "huozhe" in Mandarin Chinese. Finally, using Felicity Judgment task (Chierchia et al.2001), Experiment5measured children’s knowledge of the information strength of scalar terms, i.e., the disjunction word "huozhe" vs. the conjunction word "he".(2) To explore interpretation of logical words in Mandarin-speaking high-functioning children with autism spectrum disorders, we utilized a Computer-based Truth Value Judgment task, and assessed a group of284-15-year-old high-functioning children with autism spectrum disorders (ASD) and a control group of28typically developing (TD) children. This experimental study also supplements our previous investigation in preschool children’s interpretation of logical words, with a particular focus on4-15-year-old TD children’s development of pragmatic knowledge of logical words. These subjects were further divided into four groups according to diagnosis (ASD vs. TD) and age (Younger vs. Older): ASD/younger, ASD/older, TD/younger, and TD/older. The four groups of subjects participated in two experiments which assessed their semantic and pragmatic knowledge of logical words including (a) the existential quantifier "youxie"(English:some) and (b) the disjunction word "huozhe" in sentences with the universal quantifier "mei".Results:(1) The results of experimental studies into preschool Mandarin-speaking young children’s initial interpretation of logical words were summarized below:(a) The two semantic experiments assessing Mandarin-speaking children’s interpretation of the disjunction word "huozhe" in sentences with the universal quantifier "mei" revealed their adult-like competence with the asymmetric universal. Experiment1showed that Mandarin-speaking children assigned a conjunctive entailment to disjunction when it appeared in the subject phrase of "mei". Moreover, they accessed the disjunctive truth conditions of disjunction when it appeared in the predicate phrase of "mei". In Experiment2, children further demonstrated their knowledge of this semantic universal when "every" and "huozhe" appeared in double object constructions. In all these semantic contexts Mandarin-speaking children’s linguistic behaviors showed no differences from adult speakers (ps≥0.21).(b) The three pragmatic experiments, nevertheless, revealed young children’s insensitivity to scalar implicatures related to the scalar term "huozhe" in Mandarin Chinese, and thus they always stick to the inclusive-or interpretation of "huozhe", as in classical logic. In Experiment3, Mandarin-speaking adults’ pragmatic interpretation of disjunction was subject to the semantic contexts it appeared, whereas children always accepted disjunction based on its logical interpretation, showing a different interpretive pattern from adults (p<0.001). Experiment4further confirmed that unlike Mandarin-speaking adults, children didn’t derive scalar implicatures related to the scalar term "huozhe"(p<0.001). Yet children knew the information strength revealed by the disjunction word "huozhe" vs. the conjunction word "he" when alternative representations containing these scalar terms were explicated presented together, as demonstrated in Experiment5.(2) The results of interpretation of logical words in4-15-year-old Mandarin-speaking high-functioning children with autism spectrum disorders (ASD), as well as4-15-year-old typically developing (TD) children were summarized below.(a) In the semantic experiment, we found that TD children showed full competence with both simple senentences with "youxie" and complicated sentences with "mei...huozhe...", with correct judgmental rates almost at ceiling. The results are in consistent with our findings that typically-developing children mastered the semantics of these logical words at the early stages of language acquisition. Nevertheless, children with ASD’s performances differ with the degree of complexity of the experimental stimuli. Specifically, children with ASD showed no differences from their TD peers in understanding simple sentences with "youxie". However, they demonstrated a developmental delay with complicated sentences with "mei...huozhe...". In particular, ASD/younger group had more difficulties than TD/younger group with both true and false "mei...huozhe..." sentences (ps≤0.01). ASD/older group performed better than ASD/younger group in both conditions (ps≤0.04), with correct judgments reaching100%when presented with false "mei...huozhe" sentences; but their correct judgments for the true "mei...huozhe" sentences were still lower than the TD controls (ASD/older:76%, TD/older:93%), though this group difference doesn’t reach statistical significance.(b) In the pragmatic experiment, children with ASD didn’t differ significantly from TD controls in their pragmatic interpretations of logical words within the two age groups and across the two scalar terms "youxie" and "huozhe"(ps≤0.38). This was confirmed by the similar distribution of pragmatic/logic responders within the two age groups of ASD vs. TD participants (ps≥0.31). In addition, in both ASD and TD groups, there are similar patterns of development in children’s pragmatic interpretation of logical words, so that older children computed more scalar implicatures and thus provided more pragmatic interpretations than younger children (ps≤0.05). We also found that children tend to provide more pragmatic interpretations for scalar term "youxie" than "huozhe"(also presented in more complicated structures with "mei"), across the two age groups of ASD and TD participants (ps≤0.001). However, different from TD controls, some of the participants in the ASD group had apparent difficulties in providing appropriate justifications for their rejection of the test sentences based on pragmatic interpretations.Conclusion:(1) With respect to acquisition of logical words in typically-developing children:(a) At the initial stage of language acquisition, the meanings Mandarin-speaking preschool children assign to logical words such as the disjunction word "huozhe" and the universal quantifier "mei" correspond to their counterparts in classical logic. Taken together with previous English studies, our findings lead to the conclusion that the logical interpretations of these logical words appear across different language communities and emerge early in language development, thus yielding compelling supporting evidence for logical nativism (Crain2012).(b) Children showed an apparent developmental pattern with their knowledge of scalar implicatures. Different from adults, young preschool children appear to be insensitivity to the<or, and> scale. In addition, the developmental study in4-15-year-old children shows that older children compute more scalar implicatures and thus yield more pragmatic interpretations for "huozhe" than younger children; and their performances in the<some, all> scale are significantly better across all age groups.(2) With respect to Mandarin-speaking high-functioning children with ASD:First, although the ASD group demonstrated a developmental delay in their semantic knowledge of complicated structures, this may not be considered as a total disruption of their grammatical system, as children grow out of their difficulties in some contexts and that they may suffer from deficits in cognitive flexibility in other experimental settings. Second, this seems to be a universal pattern that knowledge of scalar implicatures may be similar between high-functioning ASD group and the TD group across all ages, despite the ASD group’s well-documented deficits in other aspects of pragmatics.