Vocal interaction dynamics of children with and without autism

Vocal Interaction Dynamics of Children With and Without Autism Anne S. Warlaumont (awarlmnt@memphis.edu) D. Kimbrough Oller (koller@memphis.edu) Speech-Language Pathology, University of Memphis, 807 Jefferson Ave. Memphis, TN 38105 USA Rick Dale (radale@memphis.edu) Department of Psychology, University of Memphis, 202 Psychology Building Memphis, TN 38152 USA Jeffrey A. Richards (JeffRichards@lenafoundation.org) Jill Gilkerson (JillGilkerson@lenafoundation.org) Dongxin Xu (DongxinXu@lenafoundation.org) LENA Foundation, 5525 Central Ave., Suite 100 Boulder, CO 80301 USA Abstract Interaction and Contingency in Language Development This study examines the temporal and directional characteristics of child-adult vocal exchanges in day-long naturalistic recordings of autism and typical control groups. In both populations, adults responded frequently (on average about 40% of responses) within 1s or less, a time thought to be conducive for contingency learning by the child. However, the time to adult response tended to be longer for the autism population. In the autism group, children also tended to follow more and lead less relative to the control group, as measured by differences in diagonal recurrence profiles computed based on cross recurrence plots. The results inform on the dynamics of naturalistic communicative interaction in normal development and therefore on the social context in which language develops. They also illustrate how large datasets and modern interaction analyses can expand our understanding of differences in children with autism, a population with both social and language deficits. The fact that language learning occurs in a dynamic and interactive social context is becoming increasingly appreciated. Children are not passive information processors nor do they learn language purely on the basis of contingent reinforcement. They are, rather, actively engaged in perceptual learning and responding to communicative acts produced by others as well as being engaged in behavioral and motor exploration for which they at least sometimes receive feedback in the form of communicative response by adults and other children in their environment. For example, in a video-recording study performed in the participants’ homes, Keller et al. (1999) found that mothers often respond within one second to their three-month-old infants’ communicative acts. Relating this to the fact that one second had been previously shown to be about the amount of time within which a contingent response must occur in order for the infant to detect that contingency, the authors concluded that mothers’ communicative responses to their infants’ communicative attempts tend to occur within the necessary window of time for the infant to perceive them as contingent. In other words, their results support the notion that caregivers’ responses to their children support infant communicative development by serving as contingent reinforcers for the infant’s own communicative acts. In a more recent study, Gros-Louis et al. (2006) observed naturalistic interactions in a laboratory setting and found that mothers responded contingently to their infant’s vocalizations over 70% of the time and that the type of response they gave depended on the phonological characteristics of the infant’s vocalizations. Furthermore, Goldstein, King, and West (2003) and Goldstein and Schwade (2008) have found experimentally that mothers’ contingent responses do appear to shape the infant’s speech- Keywords: Social interaction; autism; temporal dynamics; cross recurrence; language development; naturalistic recording; response time; social contingency Introduction In this paper, we examine fundamental issues related to the fine-grained temporal organization of vocal interaction between children and their social environment, primarily, caregivers. Recent years have seen an abundance of interest in joint action and coordinative processes in both children and adults (Galantucci & Sebanz, 2009). In the current study, we make use of latency response measures as well as the technique of cross recurrence analysis to identify leading and following patterns in the vocal exchanges between children and adults. We find a distinct signature of leading in normal children and find that a distinct breakdown of this signature is identifiable in children with autism. These results show that analysis of naturalistic recordings may reveal socio-dynamic indicators of at-risk children. We conclude with a brief discussion of the relevance of our findings to models of language acquisition in normal and disordered individuals.