On Social Feedback Loops and Cascading Effects in Autism: A Commentary on Warlaumont, Richards, Gilkerson, and Oller (2014).

Commentary Warlaumont, Richards, Gilkerson, and Oller (2014) described a social feedback loop whereby greater contingency of parents' responses to their children's speechlike vocalizations predicts their children's production of more speechlike vocalizations. In applying this model to autism spectrum disorder (ASD), Warlaumont et al. reported two primary findings: First, children with ASD produced fewer speechlike vocalizations than did typically developing (TD) children, and second, the responses of parents of autistic children were less contingent on their children's vocalizations being speech related than were the responses of parents of TD children. The authors proposed that this disruption in the social feedback loop has cascading effects that may help explain the atypical speech development characteristic of ASD. We critique the application of this model to ASD on two grounds: It fails to take into account the well-documented motor difficulties of autistic individuals, and, in privileging speech, it overlooks the dynamic nature of communicative motivation. Warlaumont et al. acknowledged that motor differences may lead autistic children to produce fewer vocal-izations than TD children do. But their model does not account for autistic children's specific difficulty in producing speechlike sounds. There is a high comorbidity between autism and apraxia, a motor disorder affecting the ability to coordinate the movements necessary for speech. The prevalence of childhood apraxia is 0.1% to 0.2% among the general population (Shriberg, Aram, & Kwiatkowski, 1997), but may be as high as 60% among autistic children (Tierney et al. Strandt-Conroy, 2012). If individuals cannot reliably produce speechlike sounds, a model of speech development that assumes they can does not seem relevant or appropriate. Indeed, an intervention based on this model could in theory be harmful to autistic children's communicative development. Parents trained to privilege speechlike vocalizations may not attend to their children's other communicative attempts. In an ongoing study, we have found that parents of nonspeaking autistic children report that their children successfully communicate their physical and emotional needs through proximity, body posture , and touch. Over time, not responding to these communicative bids could have cascading effects whereby children who have difficulty producing speech-like sounds make fewer and fewer attempts to communicate in these other ways. Warlaumont et al. speculated that another reason for autistic children producing fewer vocalizations than TD children may involve differences in their intrinsic motivation to communicate. This argument is common in the autism literature, but we find it dangerous and circular; often the only evidence …