“…We provide a bi-directional mechanistic explanation that involves the organism and its sociolinguistic environment - the ongoing interaction between infants’ perception and maternal scaffolding (Gogate & Hollich, 2010, 2013; Sullivan & Horrowitz, 1983; Yu, Ballard & Aslin, 2005). In general, caregivers coordinate their use of higher pitch, exaggerated intonation contours, elongated speech and longer pauses between utterances (Cooper, Abraham, Berman, & Statska, 1997; Fernald & Simon, 1984; Kitamura & Burnham, 2003) with simultaneous visual mouth movements (Bahrick & Pickens, 1988; Dodd, 1979; Legerstee, 1990; Meltzoff & Kuhl, 1994), more animated head movements and facial expressions (Smith & Strader, 2014; Walker-Andrews, 1997), and gestures using hands and body (Brand, Baldwin & Ashburn, 2002; Brand & Tapscott, 2007). This coordinated information is amodal , invariant , and redundant; the same information conveyed to one sense modality is conveyed to another in the form of a common temporal structure, tempo, rhythm, and spatial colocation (see review by Gogate & Hollich, 2010).…”