نشریه پژوهشهای زبانشناسی (May 2021)
Comparing the Ability of Perceptual Simulation in Children with Developmental Dyslexia and Typical Children: An Embodied Cognition View
Abstract
AbstractOne controversial issue in embodied cognition is that lower cognitive abilities (e.g. perception) influence higher cognitive abilities (e.g. language). In particular, with regard to this idea, several studies have shown that visual perception and visual imagery share common neural representations. However, it is an open question whether visual perception deficit could influence perceptual simulation during language comprehension. To clarify this issue we carried out a behavioral experiment, using sentence-picture verification task to examine the extent to which children with developmental dyslexia can simulate the shape and orientation of an object implicitly described in the sentence. Seventeen children aged between 8 and 13 years with dyslexia and 17 age-matched control subjects participated in this study. Data analyses showed a significant difference between two groups and revealed that in the typically developed group reaction time for matching condition was faster than mismatching condition, whereas children with dyslexia were less able to distinguish between two conditions. The results showed that perceptual experiences can modify the subsequent processing of perceptual (visual) imagery and also suggest that visual perception and visualization during language processing share common representations. In addition, the finding highlights the influence of visual perception on language comprehension.Keywords:Embodied cognition, Language comprehension, Perceptual simulation, Children with developmental dyslexia, Typical children IntroductionRecent research on the nature of language processing has explored the important role of body in language comprehension. The theory of embodied cognition in cognitive sciences suggests that sensorimotor experiences play an important role in acquiring and representing conceptual knowledge (Borghi & Cimatti, 2010). According to this framework, higher cognitive abilities like language and memory depend on the activation of lower cognitive abilities, such as perception and action (Gallese & Lakoff, 2005). It means that the same neural processes used in nonlinguistic functions like action, perception or emotion also activate during language comprehension (Jirak et al., 2010). Therefore, not only language processing and comprehension are acquired through activation of linguistic structures, but also comprehenders should activate sensorimotor experiences during language comprehension (Zwaan & Madden, 2005). A growing body of behavioral studies have supported the idea that the process of language comprehension leads to the activation of perceptual simulation and during sentence comprehension, comprehenders can automatically activate perceptual information of objects, including such characteristics as shape (Madden & Zwaan, 2006; Zwaan, Stanfield & Yaxely, 2002), location (Liu & Bergen, 2016), and orientation (Stanfield & Zwaan, 2001).While there has been a good deal of work on the involvement of embodied experiences in language processing, little work has addressed the relationship between visual perception impairment and perceptual (visual) imagery processing during language comprehension. Therefore, the aim of this study is to find out whether children with developmental dyslexia (DD) can process information about the shape and orientation of an object implicitly described in the sentence. In order to investigate this issue and also to clarify the relationship between perceptual simulations and language comprehension deficiency in the DD group, we compared dyslexics and age and gender-matched control group by using sentence-picture verification task. Based on previous evidence indicating visual perception impairments in DD, we predicted that in comparison to typically developing control children(TD), dyslexics would perform weaker in perceptual simulation task, and their difficulties in working memory would impact their accuracy in matching pictures with sentences. Materials & MethodsThirty four native Iranian children from grades 2 through 6 (aged between 8 to 13 years old) participated in this study. A group of 17 children with developmental dyslexia with mild to moderate degrees of reading disorder (12 boys and 5 girls; mean age= 10.6, SD= 1.51) and a group of 17 typical control children (12 boys and 5 girls; mean age= 10.3, SD= 1.41) were selected. In both groups the children were matched pairwise on chronological age and gender. Children with DD were recruited for participation through rehabilitation centers and special centers for language and learning disabilities. The TD group consisted of a subset of children who were recruited from state primary schools in the city of Shiraz. The diagnoses for dyslexics group were based on several sources of information as 1) assessment by psychiatric specialist or teacher report, 2) intelligence test: Persian version of the Wechsler Intelligence Scale for Children (WISC-IV), subjects with IQ level below 80 were excluded, 3) Bender Visual Motor Gestalt test and 4) Persian version of the Wepman auditory discrimination test (WADT).Forty pairs of Persian sentence-pictures in the format of "Agent saw the object in/on the location" similar to materials used in Engelen et al. (2011) study were constructed. We tried to select objects and situations that are comprehensible for Iranian children. Each pair consisted of two sentences that described the same object (e.g., tomato) in two different locations (e.g., "in the basket" or "on the pizza"). In this list, 32 sentence- pictures served as main items (16 in the match condition and requiring a "yes" response; 16 in the mismatch condition and requiring a "no" response) and 8 items created as fillers that all required a "no" response; they were created by a picture of the location in order to prevent participants from paying attention to the direct object. For each pair one picture was selected, such that in the match condition the shape of the related object was congruent with the shape and orientation of the picture and in the mismatch condition the shape of the related object was incongruent with the shape and orientation of the picture. All the pictures were full-color depictions of objects that were chosen from web libraries and adjusted approximately in size of 10 × 15 cm and were laid in the center of the screen. Discussion of Results and ConclusionsThe aim of the present study was to clarify the relationship between visual perception deficit and mental (visual) imagery during language comprehension. Our findings support our hypothesis in that significant differences were seen between children with developmental dyslexia and typical control children. TD children were faster to make judgment when the picture was congruent with the shape or orientation implied in the sentence. By contrast, dyslexics were less able to activate mental (visual) representations of objects and spent more time to verify matching picture than mismatching one. Although, the mechanisms underlying the observed low ability of DD group at mental imagery are unknown, we consider three possible explanations.In conclusion, the study suggests that perceptual processing of the shape and orientation of objects in sentences are influenced by perceptual experiences and cognitive skills. More importantly, the finding suggests that deficits in visual imagery ability may be due to less connectivity in brain areas related to visual perception processing or working memory deficit observed in many children with developmental dyslexia.
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