References
- American Psychiatric Association (APA). (2013). Diagnostic and statistical manual of mental disorders (DSM-V) (5th ed.). American Psychiatric Association.
- Anderson, D. K., Liang, J. W., & Lord, C. (2014). Predicting young adult outcome among more and less cognitively able individuals with autism spectrum disorders. Journal of Child Psychology and Psychiatry, 55(5), 485–494. https://doi.org/10.1111/jcpp.12178
- Annaz, D., Karmiloff-Smith, A., Johnson, M. H., & Thomas, M. S. (2009). A cross-syndrome study of the development of holistic face recognition in children with autism, Down syndrome, and Williams syndrome. Journal of Experimental Child Psychology, 102(4), 456–486. https://doi.org/10.1016/j.jecp.2008.11.005
- Asada, K., & Itakura, S. (2012). Social phenotypes of autism spectrum disorders and Williams syndrome: Similarities and differences. Frontiers in Psychology, 3, 247. https://doi.org/10.3389/fpsyg.2012.00247
- Baranek, G. T., Barnett, C. R., Adams, E. M., Wolcott, N. A., Watson, L. R., & Crais, E. R. (2005). Object play in infants with autism: Methodological issues in retrospective video analysis. The American Journal of Occupational Therapy, 59(1), 20. https://doi.org/10.5014/ajot.59.1.20
- Baron-Cohen, S. (1987). Autism and symbolic play. British Journal of Developmental Psychology, 5(2), 139–148. https://doi.org/10.1111/j.2044-835X.1987.tb01049.x
- Bates, E., Benigni, L., Bretherton, I., Camaioni, L., & Volterra, V. (1979). The Emergence of Symbols: Cognition and Communication in Infancy. Academic Press.
- Bayley, N. (2005). Bayley scales of infant development. Harcourt Assessment, Psych. Corporation.
- Belsky, J., & Most, R. K. (1981). From exploration to play: A cross-sectional study of infant free play behavior. Developmental Psychology, 17(5), 630. https://doi.org/10.1037/0012-1649.17.5.630
- Bhat, A. N., Downing, K., Galloway, J. C., & Landa, R. J. (2009). A comparison of object exploration strategies between infant siblings of children with autism and typically developing infants at 6 months of age. Poster presented at the annual international meeting for autism research. Chicago, IL. https://imfar.confex.com/imfar/2009/Webprogram/Paper3384.html
- Bottema‐Beutel, K., Malloy, C., Lloyd, B. P., Louick, R., Joffe‐Nelson, L., Watson, L. R., & Yoder, P. J. (2018). Sequential associations between caregiver talk and child play in autism spectrum disorder and typical development. Child Development, 89(3), e157–e166. https://doi.org/10.1111/cdev.12848
- Brock, J. (2007). Language abilities in Williams syndrome: A critical review. Development and Psychopathology, 19(1), 97–127. https://doi.org/10.1017/S095457940707006X
- Brugman, H., Russel, A., & Nijmegen, X. (2004). Annotating Multi-media/Multi-modal resources with ELAN. Paper presented at the LREC. Lisbon, Portugal.
- Bruner, J. S. (1973). Organization of early skilled action. Child Development, 44(1), 1–11. https://doi.org/10.2307/1127671
- Campbell, S. B., Leezenbaum, N. B., Mahoney, A. S., Moore, E. L., & Brownell, C. A. (2016). Pretend play and social engagement in toddlers at high and low genetic risk for autism spectrum disorder. Journal of Autism and Developmental Disorders, 46(7), 2305–2316. https://doi.org/10.1007/s10803-016-2764-y
- Casby, M. W. (2003). Developmental assessment of play: A model for early intervention. Communication Disorders Quarterly, 24(4), 175–183. https://doi.org/10.1177/15257401030240040301
- Cattaneo, L., Fabbri-Destro, M., Boria, S., Pieraccini, C., Monti, A., Cossu, G., & Rizzolatti, G. (2007). Impairment of actions chains in autism and its possible role in intention understanding. Proceedings of the National Academy of Sciences, 104(45), 17825–17830. https://doi.org/10.1073/pnas.0706273104
- Chaudry, M., & Dissanayake, C. (2015). Pretend play in children with Autism spectrum disorders. In S. Douglas & L. Stirling (Eds.), Children’s play, pretense, and story: Studies in culture, context, and autism spectrum disorder (pp. 31–50). Routledge.
- Christensen, L., Hutman, T., Rozga, A., Young, G. S., Ozonoff, S., Rogers, S. J., Baker, B., & Sigman, M. (2010). Play and developmental outcomes in infant siblings of children with autism. Journal of Autism and Developmental Disorders, 40(8), 946–957. https://doi.org/10.1007/s10803-010-0941-y
- Cohen, J. (1988). Statistical analysis for the behavioral sciences. Lawrance Erlbaum.
- Connolly, K., & Elliott, J.M. (1972). The evolution and ontogeny of hand function. In: Blurton-Jones, N. (Ed). Ethological studies of child behaviour. Cambridge University Press, Cambridge, pp. 329-383.
- Dominguez, A., Ziviani, J., & Rodger, S. (2006). Play behaviours and play object preferences of young children with autistic disorder in a clinical play environment. Autism, 10(1), 53–69. https://doi.org/10.1177/1362361306062010
- Ewart, A. K., Morris, C. A., Atkinson, D., Jin, W., Sternes, K., Spallone, P., Stock, A. D., Leppert, M., & Keating, M. T. (1993). Hemizygosity at the elastin locus in a developmental disorder, Williams syndrome. Nature Genetics, 5(1), 11–16. https://doi.org/10.1038/ng0993-11
- Fein, G. G. (1979). Pretend play: New perspectives. Young Children, 34(5), 61–66.
- Fenson, L., Kagan, J., Kearsley, R. B., & Zelazo, P. R. (1976). The developmental progression of manipulative play in the first two years. Child Development, 47(1), 232–236. https://doi.org/10.2307/1128304
- Gesell, A., & Ilg, F. L. (1937). Feeding behavior of infants. JB Lippincott.
- Gibson, E. J. (1988). Exploratory behavior in the development of perceiving, acting, and the acquiring of knowledge. Annual Review of Psychology, 39(1), 1–42. https://doi.org/10.1146/annurev.ps.39.020188.000245
- Gotham, K., Pickles, A., & Lord, C. (2009). Standardizing ADOS scores for a measure of severity in autism spectrum disorders. Journal of Autism and Developmental Disorders, 39(5), 693–705. https://doi.org/10.1007/s10803-008-0674-3
- Halverson, H. M. (1943). The development of prehension in infants. In R. G. Barker, J. S. Kounin, & H. F. Wright (Eds.), Child development and behaviour. (p. 49-65). McGraw-Hill.
- Harrop, C., Green, J., Hudry, K., & Consortium, P. A. C. T. (2017). Play complexity and toy engagement in preschoolers with autism spectrum disorder: Do girls and boys differ? Autism, 21(1), 37–50. https://doi.org/10.1177/1362361315622410
- Hill, P. M., & McCune-Nicolich, L. (1981). Pretend play and patterns of cognition in Down’s syndrome children. Child Development, 52(2), 611–617. https://doi.org/10.2307/1129181
- Hobson, R. P. (1990). On acquiring knowledge about people and the capacity to pretend: Response to Leslie (1987). Psychological Review, 97(1), 114–121. https://doi.org/10.1037/0033-295X.97.1.114
- Hocking, D. R., Bradshaw, J. L., & Rinehart, N. J. (2008). Fronto-parietal and cerebellar contributions to motor dysfunction in Williams syndrome: A review and future directions. Neuroscience & Biobehavioral Reviews, 32(3), 497–507. https://doi.org/10.1016/j.neubiorev.2007.09.003
- Hofferth, S. L., & Sandberg, J. F. (2001). How American children spend their time. Journal of Marriage and Family, 63(2), 295–308. https://doi.org/10.1111/j.1741-3737.2001.00295.x
- Howlin, P., Davies, M., & Udwin, O. (1998). Syndrome specific characteristics in Williams syndrome: To what extent do early behavioural patterns persist into adult life? Journal of Applied Research in Intellectual Disabilities, 11(3), 207–226. https://doi.org/10.1111/j.1468-3148.1998.tb00062.x
- Jarrold, C. (1997). Pretend play in autism: Executive explanations. In J. Russell (Ed.), Autism as an executive disorder (pp. 101–140). Oxford University Press.
- Järvinen, A., Korenberg, J. R., & Bellugi, U. (2013). The social phenotype of Williams syndrome. Current Opinion in Neurobiology, 23(3), 414–422. https://doi.org/10.1016/j.conb.2012.12.006
- Kanner, L. (1943). Autistic disturbances of affective contact. Nervous Child, 2(3), 217–250.
- Kaur, M., Srinivasan, S. M., & Bhat, A. N. (2015). Atypical object exploration in infants at-risk for autism during the first year of life. Frontiers in Psychology, 6, 798. https://doi.org/10.3389/fpsyg.2015.00798
- Klein-Tasman, B. P., Mervis, C. B., Lord, C., & Phillips, K. D. (2007). Socio-communicative deficits in young children with Williams syndrome: Performance on the Autism Diagnostic Observation Schedule. Child Neuropsychology, 13(5), 444–467. https://doi.org/10.1080/09297040601033680
- Klein-Tasman, B. P., Phillips, K. D., Lord, C. E., Mervis, C. B., & Gallo, F. (2009). Overlap with the autism spectrum in young children with Williams syndrome. Journal of Developmental and Behavioral Pediatrics, 30(4), 289. https://doi.org/10.1097/DBP.0b013e3181ad1f9a
- Koterba, E. A., Leezenbaum, N. B., & Iverson, J. M. (2014). Object exploration at 6 and 9 months in infants with and without risk for Autism. Autism: The International Journal of Research and Practice, 18(2), 97–105. https://doi.org/10.1177/1362361312464826
- Lai, N. K., Ang, T. F., Por, L. Y., & Liew, C. S. (2018). The impact of play on child development-a literature review. European Early Childhood Education Research Journal, 26(5), 625–643. https://doi.org/10.1080/1350293X.2018.1522479
- Leslie, A. M. (1987). Pretense and representation: The origins of” theory of mind.”. Psychological Review, 94(4), 412. https://doi.org/10.1037/0033-295X.94.4.412
- Libby, S., Powell, S., Messer, D., & Jordan, R. (1998). Spontaneous play in children with autism: A reappraisal. Journal of Autism and Developmental Disorders, 28(6), 487–497. https://doi.org/10.1023/A:1026095910558
- Libertus, K., Sheperd, K. A., Ross, S. W., & Landa, R. L. (2014). Limited fine motor and grasping skills in 6-month-old infants at high risk for autism. Child Development, 85(6), 2218–2231. https://doi.org/10.1111/cdev.12262
- Lifter, K., & Bloom, L. (1998). Intention and the role of play in the transition to language. In A. M. Wetherby, S. F. Warren, & J. Reichle (Eds.), Transitions in prelinguistic communication (Vol. 7, pp. 161–196). Paul H Brookes Publishing Company.
- Lifter, K., & Bloom, L. (1989). Object knowledge and the emergence of language. Infant Behavior & Development, 12(4), 395–423. https://doi.org/10.1016/0163-6383(89)90023-4
- Lifter, K., Sulzer-Azaroff, B., Anderson, S. R., & Cowdery, G. E. (1993). Teaching play activities to preschool children with disabilities: The importance of developmental considerations. Journal of Early Intervention, 17(2), 139–159. https://doi.org/10.1177/105381519301700206
- Lillard, A. S. (2015). The development of play. Handbook of Child Psychology and Developmental Science, 1–44.
- Lillard, A. S., Lerner, M. D., Hopkins, E. J., Dore, R. A., Smith, E. D., & Palmquist, C. M. (2013). The impact of pretend play on chil- dren’s development: A review of the evidence. Psychological Bulletin, 139(1), 1–34. https://doi.org/10.1037/a0029321
- Lincoln, A. J., Searcy, Y. M., Jones, W., & Lord, C. (2007). Social interaction behaviors discriminate young children with autism and Williams syndrome. Journal of the American Academy of Child and Adolescent Psychiatry, 46(3), 323–331. https://doi.org/10.1097/chi.0b013e31802b9522
- Lockman, J. J., & McHale, J. P. (1989). Object manipulation in infancy. In J.J. Lockman & N.L. Hazen (Eds.), Action in social context: Perspectives on early development (pp. 129–167). New York: Plenum.
- Lord, C., Risi, S., Lambrecht, L., Cook, E., Jr, Leventhal, H., DiLavore, B. L., … Rutter, M. (2000). The Autism diagnostic observation schedule-generic: A standard measure of social and communication deficits associated with the spectrum of autism. Journal of Autism and Developmental Disorders, 30(3), 205–223. https://doi.org/10.1023/A:1005592401947
- Lord, C., Rutter, M., DiLavore, P. C., Risi, S., Gotham, K., & Bishop, S. (2012). Autism diagnostic observation schedule: ADOS-2. Western Psychological Services.
- Martens, M. A., Wilson, S. J., & Reutens, D. C. (2008). Research Review: Williams syndrome: A critical review of the cognitive, behavioral, and neuroanatomical phenotype. Journal of Child Psychology and Psychiatry, 49(6), 576–608. https://doi.org/10.1111/j.1469-7610.2008.01887.x
- McCune-Nicolich, L. (1981). Toward symbolic functioning: Structure of early pretend games and potential parallels with language. Child Development, 52(3), 785–797. https://doi.org/10.2307/1129078
- Mervis, C. B., Morris, C. A., Klein-Tasman, B. P., Bertrand, J., Kwitny, S., Appelbaum, L. G., & Rice, C. E. (2003). Attentional characteristics of infants and toddlers with Williams syndrome during triadic interactions. Developmental Neuropsychology, 23(1–2), 243–268.
- Mullen, E. M. (1995). Mullen scales of early learning. American Guidance Service.
- Naber, F. B. A., Bakermans-Kranenburg, M. J., van Ijzendoorn, M. H., Swinkels, S. H. N., Buitelaar, J. K., Dietz, C., van Daalen, E., & van Engeland, H. (2008). Play behavior and attachment in toddlers with Autism. Journal of Autism and Developmental Disorders, 38(5), 857–866. https://doi.org/10.1007/s10803-007-0454-5
- Newell, K. M. (1986). Constraints on the development of coordination. In M. G. Wade & H. T. A. Whiting (Eds.), Motor development in children: Aspects of coordination and control (pp. 341–360). Matinus Nijhoff.
- Ozonoff, S., Macari, S., Young, G. S., Goldring, S., Thompson, M., & Rogers, S. J. (2008). Atypical object exploration at 12 months of age is associated with autism in a prospective sample. Autism, 12(5), 457–472. https://doi.org/10.1177/1362361308096402
- Ozonoff, S., Young, G. S., Carter, A., Messinger, D., Yirmiya, N., Zwaigenbaum, L., Bryson, S., Carver, L. J., Constantino, J. N., Dobkins, K., Hutman, T., Iverson, J. M., Landa, R., Rogers, S. J., Sigman, M., & Stone, W. L. (2011). Recurrence risk for autism spectrum disorders: A baby siblings research consortium study. Pediatrics, 128(3), e488–e495. https://doi.org/10.1542/peds.2010-2825
- Papaeliou, C. F., Fryssira, H., Kodakos, A., Kaila, M., Benaveli, E., Michaelides, K., Stroggilos, V., Vrettopoulou, M., & Polemikos, N. (2011). Nonverbal communication, play, and language in Greek young children with Williams syndrome. Child Neuropsychology, 17(3), 225–241. https://doi.org/10.1080/09297049.2010.524151
- Papaeliou, C. F., Sakellaki, K., & Papoulidi, A. (2019). The relation between functional play and other forms of cooperation and word learning in ASD. Int Arch Commun Disord, 2, 012. https://doi.org/10.23937/iacod-2017/1710012
- Piaget, J. (1951). Play, dreams and imitation in childhood. Heinemann in association with the New Education Fellowship.
- Rogers, S. J., Estes, A., Lord, C., Vismara, L., Winter, J., Fitzpatrick, A., … Dawson, G. (2012). Effects of a brief Early Start Denver Model (ESDM)–based parent intervention on toddlers at risk for autism spectrum disorders: A randomized controlled trial. Journal of the American Academy of Child and Adolescent Psychiatry, 51(10), 1052–1065. https://doi.org/10.1016/j.jaac.2012.08.003
- Rothman, K. J. (1990). Statistics in nonrandomized studies. Epidemiology, 1(6), 417–418. https://doi.org/10.1097/00001648-199011000-00001
- Rubin, K. H., Fein, G. G., & Vandenberg, B. (1983). Play. In E. M. Het-herington (Ed.), Socialization, personality, and social development. Volume 4 of the Handbook of child psychology (4th ed., Editor-in-Chief: Ph. H. Mussen, pp. 693–774). Wiley.
- Sacrey, L. A. R., Germani, T., Bryson, S. E., & Zwaigenbaum, L. (2014). Reaching and grasping in autism spectrum disorder: A review of recent literature. Frontiers in Neurology, 5, 6. https://doi.org/10.3389/fneur.2014.00006
- Schopler, E., & Reichler, R. J. (1968). Psycholobiological referents for the treatment of Autism. Paper presented at the Indiana University Colloquium on Infantile Autism, Indiana.
- Sigman, M., & Ungerer, J. A. (1984). Cognitive and language skills in autistic, mentally retarded, and normal children. Developmental Psychology, 20(2), 293–302. https://doi.org/10.1037/0012-1649.20.2.293
- Sparaci, L., Northrup, J. B., Capirci, O., & Iverson, J. M. (2018). From using tools to using language in infant siblings of children with autism. Journal of Autism and Developmental Disorders, 48(7), 2319–2334. https://doi.org/10.1007/s10803-018-3477-1
- Sparaci, L., Stefanini, S., D’Elia, L., Vicari, S., & Rizzolatti, G. (2014). What and why understanding in Autism spectrum disorders and W Williams syndrome: Similarities and differences. Autism Research, 7(4), 421–432. https://doi.org/10.1002/aur.1370
- Sparaci, L., Stefanini, S., Marotta, L., Vicari, S., & Rizzolatti, G. (2012). Understanding motor acts and motor intentions in Williams syndrome. Neuropsychologia, 50(7), 1639–1649. https://doi.org/10.1016/j.neuropsychologia.2012.03.019
- Sparaci, L., & Volterra, V. (2017). Hands shaping communication: From gestures to signs. In M. Bertolaso & N. Di Stefano (Eds.), Studies in applied philosophy, epistemology and rational ethics: Vol. 38. The hand: Perception, cognition, action (pp. 29–54). Springer.
- Sparrow, S. S., Balla, D. A., & Cicchetti, D. V. (2005). Vineland II: Vineland adaptive behavior scales. American Guidance Service.
- Stefanini, S., Bello, A., Volterra, V., & Carlier, M. (2008). Types of prehension in children with Williams–Beuren syndrome: A pilot study. European Journal of Developmental Psychology, 5(3), 358–368. https://doi.org/10.1080/17405620600959381
- Stone, W. L., Lemanek, K. L., Fishel, P. T., Fernandez, M. C., & Altemeier, W. A. (1990). Play and imitation skills in the diagnosis of autism in young children. Pediatrics, 86(2), 267–272.
- Szokolszky, Á. (2016). Object use in pretend play: Symbolic or functional? In A. Costall & O. Dreier, Doing things with things (pp. 77–96). Routledge.
- Tager-Flusberg, H., Plesa Skwerer, D., Joseph, R. M., Brukilacchio, B., Decker, J., Eggleston, B., Meyer, S., & Yoder, A. (2016). Conducting research with minimally verbal participants with autism spectrum disorder. Autism, 21(7), 852–861. https://doi.org/10.1177/1362361316654605
- Thiemann-Bourque, K., Johnson, L. K., & Brady, N. C. (2019). Similarities in functional play and differences in symbolic play of children with Autism spectrum disorder. American Journal on Intellectual and Developmental Disabilities, 124(1), 77–91. https://doi.org/10.1352/1944-7558-124.1.77
- Tilton, J. R., & Ottinger, D. R. (1964). Comparison of the toy play behavior of autistic, retarded, and normal children. Psychological Reports, 15(3), 967–975. https://doi.org/10.2466/pr0.1964.15.3.967
- Toth, K., Munson, J., Meltzoff, A. N., & Dawson, G. (2006). Early predictors of communication development in young children with autism spectrum disorder: Joint attention, imitation, and toy play. Journal of Autism and Developmental Disorders, 36(8), 993–1005. https://doi.org/10.1007/s10803-006-0137-7
- Ungerer, J. A., & Sigman, M. (1981). Symbolic play and language comprehension in autistic children. Journal of the American Academy of Child Psychiatry, 20(2), 318–337. https://doi.org/10.1016/S0002-7138(09)60992-4
- Uzgiris, I. C., & Hunt, J. (1975). Assessment in infancy: Ordinal scales of psychological development. University of Illinois Press.
- van Berckelaer-onnes, I. A. (2003). Promoting Early Play. Autism, 7(4), 415–423. https://doi.org/10.1177/1362361303007004007
- Vig, S. (2007). Young children’s object play: A window on development. Journal of Developmental and Physical Disabilities, 19(3), 201–215. https://doi.org/10.1007/s10882-007-9048-6
- Vivanti, G., Yerys, B., & Salomone, E. (2019). Psychological factors in Autism Spectrum Disorders. In F. R. Volkmar (Ed.), Autism and pervasive developmental disorders. (pp. 61-88). Cambridge University Press. https://doi.org/10.1017/9781108297769.004
- Vivanti, G., & Dissanayake, C. (2014). Propensity to imitate in autism is not modulated by the model’s gaze direction: An eye‐tracking study. Autism Research, 7(3), 392–399. https://doi.org/10.1002/aur.1376
- Vivanti, G., Dissanayake, C., Zierhut, C., & Rogers, S. J. (2013). Brief report: Predictors of outcomes in the early start Denver Model delivered in a group setting. Journal of Autism and Developmental Disorders, 43(7), 1717–1724. https://doi.org/10.1007/s10803-012-1705-7
- Vivanti, G., Fanning, P. A., Hocking, D. R., Sievers, S., & Dissanayake, C. (2017). Social attention, joint attention and sustained attention in autism Spectrum disorder and Williams syndrome: Convergences and divergences. Journal of Autism and Developmental Disorders, 47(6), 1866–1877. https://doi.org/10.1007/s10803-017-3106-4
- Vivanti, G., Nadig, A., Ozonoff, S., & Rogers, S. J. (2008). What do children with autism attend to during imitation tasks? Journal of Experimental Child Psychology, 101(3), 186–205. https://doi.org/10.1016/j.jecp.2008.04.008
- Vivanti, G., & Nuske, H. J. (2017). Autism, attachment, and social learning: Three challenges and a way forward. Behavioural Brain Research, 325, 251–259. https://doi.org/10.1016/j.bbr.2016.10.025
- Vivanti, G., Trembath, D., & Dissanayake, C. (2014). Mechanisms of imitation impairment in autism spectrum disorder. Journal of Abnormal Child Psychology, 42(8), 1395–1405. 1–11. https://doi.org/10.1007/s10802-014-9874-9
- Volterra, V., Capirci, O., Pezzini, G., Sabbadini, L., & Vicari, S. (1996). Linguistic abilities in italian children with Williams syndrome. Cortex, 32(4), 663–677. https://doi.org/10.1016/S0010-9452(96)80037-2
- Vondra, J., & Belsky, J. (1989). Infant play at one year. In J. Lockman, A. Hazen (Eds.), Action in social context (pp. 173–206). Springer.
- Weisler, A., & McCall, R. R. (1976). Exploration and play: Resume and redirection. American Psychologist, 31(7), 492. https://doi.org/10.1037/0003-066X.31.7.492
- Wetherby, A. M., Watt, N., Morgan, L., & Shumway, S. (2007). Social communication profiles of children with Autism spectrum disorders late in the second year of life. Journal of Autism and Developmental Disorders, 37(5), 960–975. https://doi.org/10.1007/s10803-006-0237-4
- Williams, E. (2003). A comparative review of early forms of object-directed play and parent-infant play in typical infants and young children with autism. Autism, 7(4), 361–374. https://doi.org/10.1177/1362361303007004003
- Williams, E., Costall, A., & Reddy, V. (1999). Children with autism experience problems with both objects and people. Journal of Autism and Developmental Disorders, 29(5), 367–378. https://doi.org/10.1023/A:1023026810619
- Williams, E., Reddy, V., & Costall, A. (2001). Taking a closer look at functional play in children with Autism. Journal of Autism and Developmental Disorders, 31(1), 67–77. https://doi.org/10.1023/A:1005665714197
- Wilson, K. P., Carter, M. W., Wiener, H. L., DeRamus, M. L., Bulluck, J. C., Watson, L. R., & Baranek, G. T. (2017). Object play in infants with autism spectrum disorder: A longitudinal retrospective video analysis. Autism & Developmental Language Impairments, 2, 1–12. https://doi.org/10.1177/2396941517713186
- Zelazo, P. R., & Kearsley, R. B. (1980). The emergence of functional play in infants: Evidence for a major cognitive transition. Journal of Applied Developmental Psychology, 1(2), 95–117. https://doi.org/10.1016/0193-3973(80)90002-7