“…Participating in collaborative activities very early in development seems to require a complex understanding of others' engagement; that is, their motivation to attend and stay involved in those activities. In fact, infants as young as 2 months of age show the ability to coordinate their behaviors with those of their caregivers (Fantasia, Fasulo, Costall, & López, ; Reddy, Markova, & Wallot, ; Tronick, Als, Adamson, Wise, & Brazelton, ). However, the development in infancy of the cognitive mechanisms involved in understanding others' conversations and attitudes, and inferring speakers' engagement from them, is still not completely understood (Tomasello, Carpenter, Call, Behne, & Moll, ).…”