Abstract
Background:
Autism spectrum disorder (ASD) is a neurodevelopmental disorder with 2 main symptoms of social and communication deficits and stereotyped behaviors. Pretend play and theory of mind (ToM) have an essential role in a child’s cognitive and social development.Objectives:
In this study, different variables of pretend play with levels of ToM were examined in 2 groups of typical children and children with autism.Methods:
In this case-control observational study, 45 typical children and 18 children with autism aged 5 to 7 years participated. For both groups, the ToM test was performed to measure the levels of ToM, and the child-initiated pretend play assessment (ChIPPA) was performed to analyze the pretend plays in both groups. Both tests were performed directly on children, and the scores were recorded by the examiner.Results:
The results showed a significant positive relationship between the total score of ToM and pretend play. In children with autism, there was no difference between the ToM scores regarding age (P > 0.05). There was also a significant relationship between the levels of ToM, percentage of elaborate pretend actions (PEPA), and the number of object substitutions (NOS; P < 0.001). The scores of the ToM and pretend play levels of children with autism and typical children were significantly different (P < 0.001).Conclusions:
Based on the findings, the ToM and pretend play levels were lower in ASD children than in typical children. In addition, children who had higher PEPA scores and better NOS had higher ToM scores.Keywords
Autism Spectrum Disorder Pretend Play Theory of Mind Play and Playthings Symbolic Play
1. Background
Autism spectrum disorder (ASD) is a neurodevelopmental disorder whose symptoms appear in early childhood. It is usually detectable by age 3, but for some reasons, it may not be diagnosed until pre-school age (1). According to the Centers for Disease Control and Prevention (CDC) organization (2016), 1 out of 54 children had autism, and the prevalence of the disorder is increasing (1-4). According to the diagnostic criteria in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM) (5), the symptoms of this disorder include impaired communication and social interactions, repetitive patterns of behavior or interests, and limited activities. Although these symptoms begin early, autism may not be diagnosed for a while (2, 3, 5). The symptoms of this disorder are varied in severity and mildness from one to another (2, 6).
The disorder may affect all areas of occupational performance, including social participation, play, sleep, activities of daily living (ADL), education, performance patterns, executive functions, functional skills, and personal factors (6-9). Children with ASD also have impairments in developing the theory of mind (ToM) (3, 5, 10). ToM is the ability to interpret the mental states of oneself and others to understand, explain, predict, and manipulate others’ behavior, enabling people to understand their own and others’ mental states (8, 11, 12). Play is an integral part of children’s daily life and an indicator of their developmental process. Problems in play can indicate defects in the child’s physical, cognitive, and social development (13, 14). Children with ASD usually have defects in playfulness (3, 15). Therefore, interventions have been defined to improve pretend play. Studies have shown that ToM is related to pretend play (3, 5, 8, 12), but the aspects of this relationship are unclear.
Various studies have examined the relationship between ToM and pretend play (3, 15-17), but so far, the relationship between different levels of ToM and the quality of pretend play has not been studied. Given the main concerns in social communication in children with ASD, it is crucial to discover the causes and factors that effectively improve this problem (which is the main symptom of ASD).
2. Objectives
In the present study, the relationship between different levels of ToM and the quality of pretend play was compared in children with autism aged 5 to 7 years with their typical peers. We hypothesized that children with higher pretend play skills have better scores in ToM.
3. Methods
The present study was a case-control observational design. The target population included typical children (control group) and ASD children (case group) aged 5 to 7 years old. ASD children were included in the study by the convenience sampling method, and typical children were selected by cluster sampling. The sample size in the case group was estimated at 18 and, in the control group, was determined to be 45, according to the study by Chan et al. (3). Sampling was performed in the Research Center for Developmental Disorders of Children, kindergartens, and typical schools of Hamedan Province, and the participants were homogeneous in terms of gender for the 2 groups. Inclusion criteria for ASD children were receiving a diagnosis of ASD from a psychiatrist and obtaining a score of 30 to 36 on the Gilliam Autism Rating Scale (GARS-2) test that indicates high-functioning autism (15, 16). For typically developed children, a report from their parents or teachers was required. This report consisted of parents’ and teachers’ claims of no neurological disturbances, no developmental delays, and no vision, hearing, or language problems. If children had any of the mentioned situations and problems, they would have been excluded from the study. This study was approved by the Ethics Committee of Shahid Beheshti University of Medical Sciences (code: IR.SBMU.RETECH.REC.1399.555; ethics.research.ac.ir/EthicsProposalView.php?id=151669).
The questionnaires used in this study were the GARS-2 test, the Persian version of the ToM test, and the child-initiated pretend play assessment (ChIPPA) test. Children performed both tests of ChIPPA and ToM, and the examiner rated the individual’s performance.
3.1. Questionnaire of the Persian Version of the ToM Test
The main form of this test has been designed for children aged 5 to 12 years old and administered as an interview with children. Ghamarani et al. showed that this test had satisfactory psychometric properties for use in Iran (18). In this test, the examiner shows pictures to the child and asks questions. The correct answer score is 1, and the wrong answer score is 0. The total score of the test varies from 0 to 38 and is divided into subscales as follows: (1) the first subscale (the first level of ToM): A numerical score between 0 and 20; (2) the second subscale (the second level of ToM): A numerical score between 0 and 13; and (3) the third subscale (the third level of ToM): A numerical score between 0 and 5. Higher scores indicate better performances of the child.
3.2. ChIPPA
It is a standard test designed for children aged 3 to 8 years old and has good validity and reliability (19). To use this test in children aged 5 to 7 years, the test is held for 30 minutes in 2 general categories of symbolic plays and conventional imaginary plays, in which a set of 2 scores in each subscale provides the total score of pretend play. In each general category, 3 principal scores are obtained from the child’s play: Percentage of elaborate pretend actions (PEPA) by the child, number of imitated actions (NIA) by the child, and number of object substitutions (NOS) by the child (20). Higher scores on PEPA and NOS and lower scores on NIA indicate better performances.
3.3. GARS-2 Test
The GARS-2 test is a diagnostic scale of autism developed by Gilliam in 1994. This test has 4 subscales: Stereotyped behaviors, communication, social interaction, and developmental disorders. Each scale includes questions related to that section, which can be used for the age range of 3 to 22 years. This test can be completed and scored by a therapist or parent at home or school. The validity and reliability of this test were confirmed in a previous study (21). Higher scores on this test indicate greater severity of autism symptoms. Scores below 30 exclude the diagnosis of autism, scores between 30 and 36 indicate mild to moderate autism, and scores between 36 and 60 indicate severe autism.
To interpret the data, first, the normality of data distribution was checked by the Shapiro-Wilk test. Then, in normal data, groups were compared by one-way analysis of variance (ANOVA) and Tukey post hoc test, and abnormal data were compared by the non-parametric Mann-Whitney test. Also, independent sample t-test was used where two groups comparison was needed. Finally, the Pearson correlation test was used to determine the relationship between comparethe play and ToM scores. Data analysis was performed using SPSS version 20 (SPSS Inc, Chicago, Ill, USA) at a significance level of 0.05.
4. Results
In the present study, 63 children with a mean age of 5.98 ± 0.81 years participated. The youngest and oldest children were 5 and 7 years old, respectively. Also, 21 (33.3%) were girls, and 42 (66.7%) were boys. In this study, children were divided into 2 groups. The first group (n = 18) included children with high-functioning autism (case group) and the second group (n = 45) included typically developed children (control group). There was no significant difference between the ages of the 2 groups (P = 0.92). In the control group, the scores of ToM was increased with age, but in the group of children with autism, there was no relationship between age and scores of ToM (Figure 1).
The chart shows the scores of typical children, and the chart below shows the children with autism. The vertical line represents the mind level scores, and the horizontal line represents the age.
The results of the independent sample t test showed a statistically significant difference between the 2 groups in terms of the mean total score of the ToM test, levels 1 and 2 of mental development score (P < 0.001). Since level 3 of the mental developmental part of the ToM test was not completed by all children in the case group, it was impossible to calculate a statistical test to compare the mean of the 2 groups. Table 1 compares the total scores and subscales of the ToM in the case and control groups.
Comparing the Mean Levels of the Theory of Mind in Typical Children and Children with High-Functioning Autism
| Categories | Mean ± SD | Minimum - Maximum | 95% CI | P Value | |
|---|---|---|---|---|---|
| Upper Bound | Lower Bound | ||||
| Total score of ToM test | < 0.001 | ||||
| ASD | 9.94 ± 6.58 | 3 - 28 | 13.21 | 6.67 | |
| Typical | 28.96 ± 3.78 | 19 - 37 | 30.09 | 27.82 | |
| Level 1 | < 0.001 | ||||
| ASD | 8.78 ± 4.15 | 3 - 17 | 10.84 | 6.71 | |
| Typical | 18.22 ± 1.35 | 15 - 20 | 18.63 | 17.82 | |
| Level 2 | < 0.001 | ||||
| ASD | 1.17 ± 2.96 | 0 - 11 | 2.64 | 0 | |
| Typical | 8.80 ± 2.53 | 1 - 13 | 9.56 | 8.04 | |
| Level 3 | Not measurable | ||||
| ASD | - | - | - | - | |
The results of the independent sample t tests demonstrated a statistically significant difference between the 2 groups in conventional, symbolic, and combined PEPA. In addition, the typically developed children had higher score on PEPA than children with autism (Table 2).
Comparing the Percentage of Elaborate Pretend Actions in the Child Initiated Pretend Play Assessment in Typical Children and Children with High-Functioning Autism
| Categories | Mean ± SD | Minimum - Maximum | 95% CI | P Value | |
|---|---|---|---|---|---|
| Upper Bound | Lower Bound | ||||
| PEPA (conventional) | < 0.001 | ||||
| ASD | 46.75 ± 14.29 | 23.8 - 70.8 | 53.85 | 39.47 | |
| Typical | 89.42 ± 8.58 | 56.5 - 98.7 | 91.99 | 86.84 | |
| PEPA (symbolic) | < 0.001 | ||||
| ASD | 35.74 ± 14.77 | 0 - 58.8 | 43.08 | 28.39 | |
| Typical | 86.69 ± 11.49 | 50.5 - 100 | 90.14 | 83.23 | |
| PEPA (combined) | < 0.001 | ||||
| ASD | 43.45 ± 10.53 | 21.9 - 62.7 | 48.68 | 38.22 | |
| Typical | 87.96 ± 9.04 | 53 - 99 | 90.67 | 85.24 | |
| NOS (conventional) | 0.45 | ||||
| ASD | 0.28 ± 0.58 | 0 - 2 | 0.56 | 0 | |
| Typical | 0.62 ± 1.17 | 0 - 5 | 0.97 | 0.27 | |
| NOS (symbolic) | < 0.001 | ||||
| ASD | 2.61 ± 2.15 | 0 - 7 | 3.68 | 1.54 | |
| Typical | 16.47 ± 8.12 | 0 - 33 | 18.90 | 14.03 | |
| NOS (combined) | < 0.001 | ||||
| ASD | 2.89 ± 2.52 | 0 - 9 | 4.14 | 1.64 | |
| Typical | 17.18 ± 8.27 | 4 - 35 | 19.66 | 14.69 | |
The Mann-Whitney and independent sample t test results showed a statistically significant difference between the 2 groups in terms of the mean scores of the symbolic NOS and combined NOS. Compared with ASD children, typically developed children had higher scores in symbolic and combined NOS. However, the results of the Mann-Whitney test did not show a statistically significant difference between the 2 groups in terms of the mean scores of NOS in conventional play (P = 0.45).
The Mann-Whitney and independent sample t tests showed no statistically significant difference between the 2 groups regarding the mean scores of the conventional, symbolic, and combined NIA (P < 0.05). In other words, children with autism scored similarly to their typically developed peers in conventional, symbolic, and combined NIA.
According to Table 3, there was a positive and significant relationship between ToM and combined PEPA, as well as between ToM and conventional PEPA. However, there was no positive and significant relationship between ToM and PEPA in symbolic play.
The Pearson Correlation Test Between the Theory of Mind and Percentage of Elaborate Pretend Actions in Typical Children with Autism Aged 5 - 7 Years
| Typical Children (N = 45) | Conventional PEPA | Symbolic PEPA | Combined PEPA |
|---|---|---|---|
| Total score of ToM | |||
| Correlation | 0.301 a | 0.307 a | 0.347 a |
| Significance level | 0.044 | 0.040 | 0.020 |
| Level 1 | |||
| Correlation | 0.351 a | 0.388 b | 0.427 b |
| Significance level | 0.018 | 0.008 | 0.003 |
| Level 2 | |||
| Correlation | 0.260 | 0.232 | 0.275 |
| Significance level | 0.084 | 0.124 | 0.068 |
| Level 3 | |||
| Correlation | 0.028 | 0.067 | 0.062 |
| Significance level | 0.856 | 0.660 | 0.686 |
| Children with ASD | |||
| Total score of ToM | |||
| Correlation | 0.514 a | 0.365 | 0.649 a |
| Significance level | 0.029 | 0.137 | 0.004 |
| Level 1 | |||
| Correlation | 0.451 | 0.334 | 0.626 b |
| Significance level | 0.061 | 0.175 | 0.005 |
| Level 2 | |||
| Correlation | 0.511 a | 0.342 | 0.564 a |
| Significance level | 0.030 | 0.164 | 0.015 |
| Level 3 | |||
| Correlation | - | - | - |
| Significance level | - | - | - |
The Spearman correlation coefficient showed that ToM had no positive and significant relationship with NIA in both typical and autism children. Also, there was a positive and significant relationship between ToM with combined and symbolic NOS in both groups (P < 0.001; Table 4).
The Spearman Correlation Test Between the Theory of Mind and Number of Object Substitutions in Typical Children with Autism Aged 5 - 7 Years
| Typical Children (N = 45) | Conventional NOS | Symbolic NOS | Combined NOS |
|---|---|---|---|
| Total score of ToM | |||
| Correlation | -0.057 | 0.455 a | 0.425 a |
| Significance level | 0.712 | 0.002 | 0.004 |
| Level 1 | |||
| Correlation | 0.097 | 0.440 a | 0.443 a |
| Significance level | 0.524 | 0.003 | 0.002 |
| Level 2 | |||
| Correlation | -0.103 | 0.371 b | 0.338 b |
| Significance level | 0.502 | 0.012 | 0.023 |
| Level 3 | |||
| Correlation | -0.080 | 0.201 | 0.170 |
| Significance level | 0.601 | 0.185 | 0.265 |
| Children with ASD | |||
| Total score of ToM | |||
| Correlation | 0.362 | 0.674 a | 0.657 a |
| Significance level | 0.139 | 0.002 | 0.003 |
| Level 1 | |||
| Correlation | 0.348 | 0.676 a | 0.656 a |
| Significance level | 0.157 | 0.002 | 0.003 |
| Level 2 | |||
| Correlation | 0.318 | 0.549 b | 0.540 b |
| Significance level | 0.199 | 0.018 | 0.021 |
| Level 3 | |||
| Correlation | - | - | - |
| Significance level | - | - | - |
5. Discussion
This study aimed to compare the levels of ToM with the quality of pretend play, including NOS, PEPA, and NIA, in 5 to 7-year-old children with autism and their typically developed peers. The results showed that the ToM test scores were higher in typically developed children than in ASD children. Previous studies have also found consistent results when comparing ASD children with typical children regarding ToM (6, 10, 22-24). In this study, the total score of the first level of ToM was 9.94, which is very low compared to the maximum score of 20. According to ToM test scores, Chan et al. stated that children with high-functioning autism had prerequisites for the early ToM skills, including the perception of desires and emotions, but were not suitable for their age (3). Our results indicated that in children with autism, no growth trend was observed in ToM with age, whereas the mean scores of ToM in typical children was increased with age. According to Kabha and Berger, the stages of ToM varied at different ages (11). Nevertheless, Mansuri et al. also stated that compared with typical children, ASD children had a significant defect in ToM that was not affected by age, and it did not necessarily improve with age (7).
Based on the findings, typical children scored better than ASD children on PEPA and NOS scores. These results are in line with previous studies (13, 24). There was no significant difference between ASD and typical children regarding NIA scores. The average NIA in 2 play sets in typical children was 2.02 and in children with autism was 3.06. Lower NIA scores indicate higher levels of play. Although low NIA scores in typical children can be due to their play ideas, children with autism imitated the examiner’s actions because they did not pay enough attention. Libby et al also stated that problems of children with autism for participating in pretend play and not paying attention to the play led to problems in imitating the actions of pretend play (25). According to Strid et al., imitation in verbal and non-verbal children with autism is impaired (26), which is in line with the findings of the current research. In this study, it was also observed that PEPA and NOS were weaker in ASD children than in typical children, and serious playing defects were seen in these 2 areas.
According to the findings, there was a positive and significant relationship between ToM and PEPA in typical and ASD children. However, this significant relationship was not observed in the conventional imaginary subscales. In previous studies, ToM and play have been related, and even ToM has been called a predictor of playing quality (3, 15). Merino found a negative relationship between pretend play and ToM (27). However, that study was performed on 4-year-old children, which is not comparable to the current study population. Also, the child’s perception of himself/herself and others in the world of mind is highly associated with subsets of actions, gestures, and conversations in the play (8). Nevertheless, these results suggest that the more complex the child's pretend play and plays behaviors, the higher the ToM.
The results also showed no significant relationship between ToM and NIA in either group. Lin et al. also claimed that ToM did not predict the amount of imitation in a child’s play among children with ASD (15). However, our findings indicated a significant relationship between total NOS scores and ToM in both groups, but this relationship was not significant in the conventional imaginary set for typical and ASD children. Lillard and Kavanaugh associated symbols with ToM in 4 to 5-year-old children (28). Lin et al. stated that object substitution was not related to children’s pretend play (15). When a child begins to play, if he/she pretends to be someone else, it can be a pretense to predict ToM (29). Therefore, it can be said that a child with better ToM can place objects in his/her pretend play to a greater extent. It can also be predicted that a child, who places more objects in his/her pretend play, gains a higher score in ToM. Therefore, when a child puts himself/herself in the place of another person in his/her mental state and situations, it shows the good development of his/her ToM ability (30).
Finally, there was no relationship between ToM and NOS in conventional imaginary play. This is because the structure of this part of the play is such that the placement of objects is done to a minimal extent. In contrast, the symbolic play is used to a large extent in the placement of objects because the tools of this play are unstructured objects. However, we can generally admit that there is a positive relationship between pretend play and ToM. The results supported our hypothesis.
5.1. Conclusions
The findings showed that the levels of ToM were much lower in ASD children than in typically developed peers, and the development of ToM in ASD children did not follow the age growth pattern. In contrast, the growth of ToM in typical children followed the growth pattern, and by the age of 8, typical children were more likely to be at the second level of ToM. In addition, the mean scores of pretend play in typical children were higher than ASD children. Therefore, it can be concluded that play skills and ToM are related, and to improve one, one can rely on other interventions. To improve social functioning, play interventions can be considered by clinicians in children with ASDs. We also suggest more studies in clinical trial designs to make sure whether play interventions can improve ToM or not.
Acknowledgements
References
-
1.
Chen KL, Chen CT, Lin CH, Huang CY, Lee YC. Prediction Of Playfulness By Pretend Play, Severity Of Autism Behaviors, And Verbal Comprehension In Children With Autism Spectrum Disorder. Neuropsychiatr Dis Treat. 2019;15:3177-86. [PubMed ID: 32009787]. [PubMed Central ID: PMC6859163]. https://doi.org/10.2147/NDT.S223681.
-
2.
Case-Smith J, O'Brien J:. Occupational therapy for children and adolescents-e-book. 7 ed. Amsterdam: Elsevier Health Sciences; 2014.
-
3.
Chan PC, Chen CT, Feng H, Lee YC, Chen KL. Theory of Mind Deficit is Associated with Pretend Play Performance, but not Playfulness, in Children with Autism Spectrum Disorder. Hong Kong J Occup Ther. 2016;28(1):43-52. [PubMed ID: 30186066]. [PubMed Central ID: PMC6091989]. https://doi.org/10.1016/j.hkjot.2016.09.002.
-
4.
O'Brien JC, Kuhaneck H. Case-Smith's Occupational Therapy for Children and Adolescents-E-Book. 8 ed. Mosby: Elsevier Health Sciences; 2019.
-
5.
Szabó MK. Patterns of Play Activities in Autism and Typical Development. A Case Study. Procedia Soc Behav Sci. 2014;140:630-7. https://doi.org/10.1016/j.sbspro.2014.04.483.
-
6.
Yirmiya N, Erel O, Shaked M, Solomonica-Levi D. Meta-analyses comparing theory of mind abilities of individuals with autism, individuals with mental retardation, and normally developing individuals. Psychol Bull. 1998;124(3):283-307. [PubMed ID: 9849110]. https://doi.org/10.1037/0033-2909.124.3.283.
-
7.
Mansuri M, Chalabianloo GHR, Maleki AA, Mosaded AA. The comparison of factors affecting the theory of mind development in autistic and normal children. Arak Medical University Journal. 2010;13(4).
-
8.
Park S. Theory of mind dynamics in children's play: A qualitative inquiry in a preschool classroom. Virginia, USA: Virginia Tech; 2001.
-
9.
Şahin B, Bozkurt A, Usta MB, Aydın M, Çobanoğlu C, Karabekiroğlu K. [Theory of Mind: Development, Neurobiology, Related Areas and Neurodevelopmental Disorders]. Current Approaches in Psychiatry. 2019;11(1):62-79. Turkish. https://doi.org/10.18863/pgy.390629.
-
10.
Semeijn M. Interacting with Fictions: The Role of Pretend Play in Theory of Mind Acquisition. Rev Philos Psychol. 2018;10(1):113-32. https://doi.org/10.1007/s13164-018-0387-2.
-
11.
Kabha L, Berger A. The sequence of acquisition for theory of mind concepts: The combined effect of both cultural and environmental factors. Cogn Dev. 2020;54:100852. https://doi.org/10.1016/j.cogdev.2020.100852.
-
12.
Bao EA, Gupta S, Keshavamurthy JH, Thomson N3. Atrioesophageal fistula after AF ablation. J Cardiovasc Comput Tomogr. 2017;11(3):245-6. [PubMed ID: 28185848]. https://doi.org/10.1016/j.jcct.2017.01.008.
-
13.
Lee GT, Feng H, Xu S, Jin SJ. Increasing "Object-Substitution" Symbolic Play in Young Children With Autism Spectrum Disorders. Behav Modif. 2019;43(1):82-114. [PubMed ID: 29090595]. https://doi.org/10.1177/0145445517739276.
-
14.
Romli M. A Systematic Review on Psychometric Properties of Play Instruments for Occupational Therapy Practice. Occup Ther Int. 2020:2490519. https://doi.org/10.37766/inplasy2020.4.0156.
-
15.
Lin SK, Tsai CH, Li HJ, Huang CY, Chen KL. Theory of mind predominantly associated with the quality, not quantity, of pretend play in children with autism spectrum disorder. Eur Child Adolesc Psychiatry. 2017;26(10):1187-96. [PubMed ID: 28303423]. https://doi.org/10.1007/s00787-017-0973-3.
-
16.
Schwebel DC, Rosen CS, Singer JL. Preschoolers' pretend play and theory of mind: The role of jointly constructed pretence. Br J Dev Psychol. 1999;17(3):333-48. https://doi.org/10.1348/026151099165320.
-
17.
Wang Z, Wong RKS, Wong PYH, Ho FC, Cheng DPW. Play and theory of mind in early childhood: a Hong Kong perspective. 'Early Child Dev Care. 2016;187(9):1389-402. https://doi.org/10.1080/03004430.2016.1146261.
-
18.
Ghamarani A, Alborzi S, Khayer M. [Validity and reliability of the theory of mind test (tom test) for use in iran]. Psychology. 2006;10(2 (38)):181-99. Persian.
-
19.
Dabiri Golchin M, Mirzakhani N, Stagnitti K, Dabiri Golchin M, Rezaei M. Psychometric properties of Persian version of “child-initiated pretend play assessment” for Iranian children. Iran J Pediatr. 2017;27(1). e7053.
-
20.
Mirzakhani N, Dabiri Golchin M, Rezaee M, Tabatabaee SM, Dabiri Golchin M, Stagnitti K, et al. [Relaibility of Persian version of ChIPPA for pretend play assessment in children]. Pajoohande. 2016;21(2):87-92. Persian.
-
21.
Ahmadi SJ, Safari T, Hemmatian M, Khalili Z. [The psychometric properties of Gilliam autism rating scale (GARS)]. Research in Cognitive and Behavioral Sciences. 2011;1(1):87-104. Persian.
-
22.
Heidari T, Shamive Isfahani A, Faramarzi S. [The Comparison Theory Of Mind Dimension In Autism Children And Normal Children Isfahan City]. Knowledge & research in applied psychology. 2011;12(3 (45)):64-70. Persian.
-
23.
Peterson CC, Wellman HM, Liu D. Steps in theory-of-mind development for children with deafness or autism. Child Dev. 2005;76(2):502-17. [PubMed ID: 15784096]. https://doi.org/10.1111/j.1467-8624.2005.00859.x.
-
24.
Lam YG, Yeung SS. Cognitive deficits and symbolic play in preschoolers with autism. Res Autism Spectr Disord. 2012;6(1):560-4. https://doi.org/10.1016/j.rasd.2011.07.017.
-
25.
Libby S, Powell S, Messer D, Jordan R. Imitation of pretend play acts by children with autism and Down syndrome. J Autism Dev Disord. 1997;27(4):365-83. [PubMed ID: 9261664]. https://doi.org/10.1023/a:1025801304279.
-
26.
Strid K, Heimann M, Tjus T. Pretend play, deferred imitation and parent-child interaction in speaking and non-speaking children with autism. Scand J Psychol. 2013;54(1):26-32. [PubMed ID: 23121545]. https://doi.org/10.1111/sjop.12003.
-
27.
Merino NM. Parallel relations of pretend play, social competence, and theory of mind development in preschool aged children. California, USA: University of California, Santa Barbara; 2009.
-
28.
Lillard AS, Kavanaugh RD. The contribution of symbolic skills to the development of an explicit theory of mind. Child Dev. 2014;85(4):1535-51. [PubMed ID: 24502297]. https://doi.org/10.1111/cdev.12227.
-
29.
Dore RA, Smith ED, Lillard AS. How is theory of mind useful? Perhaps to enable social pretend play. Front Psychol. 2015;6:1559. [PubMed ID: 26528217]. [PubMed Central ID: PMC4606048]. https://doi.org/10.3389/fpsyg.2015.01559.
-
30.
Keskin B. The relationship between theory of mind, symbolic transformations in pretend play, and children's social competence. Florida, USA: Florida State University; 2005.