The Importance of Distinguishing Propensity Versus Ability to Imitate in ASD Research and Early Detection Giacomo Vivanti
Journal of Autism and Developmental Disorders ISSN 0162-3257 J Autism Dev Disord DOI 10.1007/s10803-014-2254-z
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Author's personal copy J Autism Dev Disord DOI 10.1007/s10803-014-2254-z
LETTER TO THE EDITOR
The Importance of Distinguishing Propensity Versus Ability to Imitate in ASD Research and Early Detection Giacomo Vivanti
Ó Springer Science+Business Media New York 2014
Abstract Imitation abnormalities are often documented in young children with Autism Spectrum Disorder (ASD), however the relevance of imitation to early development and early detection of ASD remains unclear. Recent studies that investigated whether imitation at 12 months distinguishes children who will subsequently receive an ASD diagnosis from other high-risk groups have reported conflicting results. The purpose of this note is to provide a framework to interpret these conflicting findings, which is based on the often-overlooked distinction between the propensity to imitate and the ability to imitate. We argue that this distinction can critically inform understanding of early imitative behaviour in ASD and the development of early detection procedures. Keywords
Imitation Autism
Dear Editor, Imitation abnormalities have been consistently documented in young children with Autism Spectrum Disorder (ASD) (Rogers and Pennington 1991; Williams et al. 2004). Nevertheless, the role of imitative deficits in the development of ASD and the relevance of imitation to early detection remain unclear. Two recent studies (Rowberry et al. 2014; Young et al. 2011) addressed this issue by investigating the relevance of G. Vivanti (&) Olga Tennison Autism Research Centre, School of Psychological Science, La Trobe University, Bundoora Campus, Melbourne, VIC 3086, Australia e-mail:
[email protected] G. Vivanti Victorian Autism Specific Early Learning and Care Centre, La Trobe University, Melbourne, VIC 3086, Australia
imitation difficulties as an early marker of ASD in 12-months-old high-risk siblings. Rowberry et al. found that poor imitation at 12 months was the most relevant marker separating high-risk children who went on to receive a diagnosis of ASD from other high-risk groups. Conversely, Young et al. (2011) found that 12-month-old children later diagnosed with ASD were indistinguishable in their imitation skills from high-risk infants who developed non-ASD-related cognitive delays. Rowberry et al. attribute this difference to the different settings involved in the two studies; participants’ imitation was measured at home, in response to their parents in the Rowberry et al. study, and in a laboratory setting, in response to an unfamiliar experimenter, in the Young et al. study. The purpose of this note is to advance an alternative explanation for these conflicting results, which is based on the often-overlooked distinction between the propensity to imitate and the ability to imitate. We argue that this distinction can inform interpretation of existing literature and development of early detection procedures. The concept of propensity refers to whether a child is inclined to use imitation spontaneously, as reflected in the frequency of imitative behaviour in everyday life. Conversely, the concept of ability refers to how accurate the child is when she or he attempts to imitate others, as reflected in the precision of imitative performance in response to the explicit instruction to imitate. These are arguably two distinct aspects; a child may imitate frequently but inaccurately, and vice versa. Moreover, these distinct aspects of imitation appear to be linked to different social and cognitive processes (Vivanti et al. 2014). The conflicting results of the two studies might reflect a lack of appreciation of this distinction. Arguably, the Young et al. study tested high-risk infants’ ability to imitate, while the Rowberry et al. study
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Author's personal copy J Autism Dev Disord
tested their propensity to imitate. Indeed, Young et al. measured how accurate participants were in imitating the experimenter when they were fully engaged in the task. Importantly, trials in which participants were not engaged were not counted in the scoring. Therefore, the performance of children with a low inclination/propensity to participate to the imitation game was not factored in the analyses. At the contrary, the measure used in the Rowberry study focused on the occurrence of imitative behaviour during playful routines between parents and their infants, rather than the accuracy of the imitation performance. Therefore, it is possible that the two studies came to opposite conclusions because they were measuring two distinct processes. This distinction can provide a helpful framework to interpret inconsistencies and conflicting results in previous literature on imitation in ASD (Vivanti and Hamilton 2014), as some studies report data on the precision of imitation in response to specific instructions (thus measuring what the child can do) and others report information on the propensity to use imitation spontaneously in everyday life (what the child does do). This distinction is particularly relevant in the context of the developmental and clinical implications of the two studies. From a developmental perspective, the propensity (or drive) to imitate others frequently might be more important than the ability to imitate actions to a high degree of precision (Trevarthen et al. 1999; Vivanti and Rogers 2014). For example, engagement in early dyadic interactions involving reciprocal imitation games does not require high-fidelity matching between parent and infant’s actions (Kugiumutzakis et al. 2005). Given the relevance of these early interactions to social-cognitive development, a child who is not inclined to engage in imitation games might be more at risk for poor social outcomes compared to a child who does imitate others, but does so to a diminished degree of accuracy. In conclusion, if the propensity to imitate others frequently, rather than the ability to imitate
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others accurately, is linked to the development of ASD, early detection tools and procedures should take into account this important distinction.
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