 An ability to appreciate what others are attending to appears to be a crucial stage in a normal infant’s development towards understanding the fact that its caregivers’ utterances have referential intentions behind them. More generally, capacities for attention develop at important milestones on the route to the acquisition of some distinctively human cognitive capacities (Moore and Dunham, 1995). There is a distinctive developmental pathway in which normal human infants develop an ability and a willingness to attend to their mother, an ability and willingness to attend to the thing that she is attending to, and then, most importantly, an ability and willingness to enter into episodes in which there is a third object that mother and child are attending to jointly, with mutual understanding of the fact that their attention is shared (Reddy, 2010, Trevarthen, 2011). In these episodes infants and caregivers employ complex cues, involving speech, gaze-following, and pointing.