We examined differences between children with autism spectrum disorder and typically developing children over an 8-month period in: (a) longitudinal associations between expressive and receptive vocabulary and (b) the extent to which caregiver utterances provided within an "optimal" engagement state mediated the pathway from early…

Purpose: Infants with autism spectrum disorder (ASD) produce fewer play actions and gestures than neurotypical infants (e.g., Mastrogiuseppe et al., 2015; Veness et al., 2012; Zwaigenbaum et al., 2005). The purpose of this study was to investigate whether different "types" of actions and gestures are more or less likely to develop…