Atypical Minds: the Cognitive Science of Difference and Potentialities
Cognitio 2015
Young researchers conference in cognitive science
Montréal, June 8th, 9th and 10th 2015
Can contrastive focus marking explain social communication difficulties in children with autistic spectrum disorders?
Lucile Rapin, Lucie Ménard, Paméla Trudeau-Fisette & Marie Bellavance-Courtemanche.
Autistic spectrum disorder (ASD) is a neurodevelopmental disorder severely affecting social communication. People suffering from this mental disorder show difficulties in interacting with others, expressing their feelings in a socially appropriated way. This translates into a stigmatisation and a marginalisation of this population. In order to improve their lifestyle, it is important to understand where social communication anomalies come from, whether it is an absence or a divergence of interpersonal skills. Speech is the major way of interacting between humans. It carries information on both linguistic information and speaker’s intentions and feelings. Within this latter function of speech, contrastive focus serves to emphasize a segment in the linguistic message in order to increase its intelligibility. Its production is generally associated with increased pitch, intensity and duration of the accented speech segment in relation to non-stressed syllables. Studies have shown that children with ASD struggle with both perceiving and producing the focus, which could explain, in part, their obstacles in interpersonal communication. With the complexity of the disorder, results are nonetheless conflicted and further research is needed to allow correct definitions of pragmatic prosody markers in subjects with ASD. In the present study we investigated the perception and the production of contrastive focus in children with ASD relative to age-matched typically developing children.
Nine children with ASD and nine typically developing children participated in the study. All were francophone and with a mean age of eight years and eight months. In both parts of the study, eight target words with at least one of the following vowels: /i y u a/ were presented six times. The words were embedded in simple four word sentences such as («C’est une sirène»: «it is a siren»). In the perception part, children had to determine whether the sentence was pronounced under contrastive focus, according to three modalities: audiovisual, audio and visual. In the production part, participants had to produce the sentences in neutral condition and in contrastive focus condition within the context of an image denomination. Speech productions were recorded using a system synchronising acoustic signals with lingual and labial movements. The perception part and the production part of the study were conducted separately in two independent sessions. For the perception test, the rate of correct answers was compared between groups for each modality of presentation. Moreover, six acoustic features were investigated: maximum, mean pitch and pitch range, maximum and mean intensity and duration, and were analyzed under Praat with mixed ANOVAs.
The perception experiment was well understood by both groups with a total identification rate of 63.19% for TYP and 56.98% for ASD. Although both TYP and ASD scores decreased in the visual mode compared to the other two modalities, this decline was more pronounced for TYP than for ASD. ASD actually had higher scores in the visual mode relative to the TYP group. With concerns to the production session, children with ASD were all able to produce sentences under both conditions. Values for pitch range, maximum and mean sound intensity and duration were greater in the focus condition than in the neutral condition. Moreover, the differences were significantly greater in TYP children than in children with ASD, who did not have increased speech values when switching to the focus mode. The present findings propose that intensity and duration correlates most with contrastive focus marking in both groups. Specifically, it appears that children with ASD struggle with perceiving the focus and mark it less compared to the TYP children. Impaired contrastive focus use could explain the difficulties in social communication encountered by children with ASD, which could seriously impact future personal and academic achievement.