We examined the ontogeny of gaze following by testing infants at 9, 10 and 11 months of age. Infants (N = 96) watched as an adult turned her head toward a target with either open or closed eyes. The 10-and 11-month-olds followed adult turns significantly more often in the open-eyes than the closed-eyes condition, but the 9-month-olds did not respond differentially. Although 9-month-olds may view others as 'body orienters', older infants begin to register whether others are 'visually connected' to the external world and, hence, understand adult looking in a new way. Results also showed a strong positive correlation between gaze-following behavior at 10-11 months and subsequent language scores at 18 months. Implications for social cognition are discussed in light of the developmental shift in gaze following between 9 and 11 months of age.

Two studies assessed the gaze following of 12-, 14-, and 18-month-old infants. The experimental manipulation was whether an adult could see the targets. In Experiment 1, the adult turned to targets with either open or closed eyes. Infants at all ages looked at the adult's target more in the open-versus closed-eyes condition. In Experiment 2, an inanimate occluder, a blindfold, was compared with a headband control. Infants 14-and 18-months-old looked more at the adult's target in the headband condition. Infants were not simply responding to adult head turning, which was controlled, but were sensitive to the status of the adult's eyes. In the 2nd year, infants interpreted adult looking as objectdirected-an act connecting the gazer and the object.Gaze following occurs when a person looks where another person just looked. Among adults, detecting the direction of another's gaze is a crucial component of social interactions (Argyle & Cook, 1976;Kleinke, 1986;Langton, Watt, & Bruce, 2000). Gaze following is important from a developmental perspective (Butterworth, 1991;Scaife & Bruner, 1975); for example, individuals with autism have profound deficits in gaze following (Baron-Cohen, 1995;Dawson, Meltzoff, Osterling, Rinaldi, & Brown, 1998;Sigman & Ruskin, 1999). Gaze following has been implicated as a building block for developing a "theory of mind" (Baldwin & Moses, 1994;Lee, Eskritt, Symons, & Muir, 1998;Meltzoff & Brooks, 2001). In particular, it is relevant for understanding the meaning of an emotional display because a person's emotion is often "about" what he or she sees in the external world (e.g., that object is pleasant vs. dangerous). One needs to be able to follow gaze to understand the cause and meaning of a person's emotional behavior (Moses, Baldwin, Rosicky, & Tidball, 2001;Repacholi, 1998). Language acquisition is also facilitated by understanding another's line of regard. In the prototypical case, a verbal label refers to the object being looked at and not the other objects that may be in the room (Baldwin, 1995;Bloom, 2002;Tomasello, 1995).The act of looking at something may take on a referential meaning even to infants (Scaife & Bruner, 1975). The common-sense view is that infants look at the same object as the adult because they want to see what the adult is seeing. From this perspective, infants implicitly understand that the other person is directing his or her own attention to something (BaronCohen, 1995;Carpenter, Nagell, & Tomasello, 1998). This interpretation grants a complex interpersonal understanding to infants because it implies that infants interpret the triadic relationship of seeing or attention between themselves, the adult, and the object (Perner, 1991).Some researchers have offered a more conservative or "leaner" interpretation of infants' gaze following (Langton et al., 2000;Moore, 1999;Moore & Corkum, 1994;Povinelli, 2001 Researchers have suggested that "looking at an object" can be processed as merely an observable movement-the movement of the gazer's head draws the infant'...

We found that infant gaze following and pointing predicts subsequent language development. At ages 0 ; 10 or 0 ; 11, infants saw an adult turn to look at an object in an experimental setting. Productive vocabulary was assessed longitudinally through two years of age. Growth curve modeling showed that infants who gaze followed and looked longer at the target object had significantly faster vocabulary growth than infants with shorter looks, even with maternal education controlled; adding infant pointing strengthened the model. We highlight the role of social cognition in word learning and emphasize the communicative-referential functions of early gaze following and pointing.

Using a gaze-following task, the authors assessed whether self-experience with the view-obstructing properties of blindfolds influenced infants' understanding of this effect in others. In Experiment 1, 12-month-olds provided with blindfold self-experience behaved as though they understood that a person wearing a blindfold cannot see. When a blindfolded adult turned to face an object, these infants gaze followed significantly less than control infants who had either (a) seen and felt the blindfold but whose view had not been obstructed by it or (b) experienced a windowed blindfold through which they could see. In Experiment 2, 18-month-olds experienced either (a) a trick blindfold that looked opaque but could be seen through, (b) an opaque blindfold, or (c) baseline familiarization. Infants receiving trick-blindfold experience now followed a blindfolded adult's gaze significantly more than controls. The authors propose 3 mechanisms underlying infants' capacity to use self-experience as a framework for understanding the visual perception of others.

This longitudinal study tested the same children at three time points: infancy (10.5 months of age), toddlerhood (2.5 years of age), and early childhood (4.5 years of age). At 10.5 months, infants were assessed experimentally with a gaze-following paradigm. At 2.5 years, children's language skills were measured using the MacArthur-Bates Communicative Development Inventories. At 4.5 years, children's explicit theory of mind was assessed with a standard test battery. Analyses revealed that infants with higher gaze-following scores at 10.5 months produced significantly more mental-state words at 2.5 years and that children with more mental-state words at 2.5 years were more successful on the theory-of-mind battery at 4.5 years. These predictive longitudinal relationships remained significant after controlling for general language, maternal education, and nonsocial attention. The results illuminate the bridging role that language plays in connecting infants' social cognition to children's later understanding of others' mental states. The obtained specificity in the longitudinal relations informs theories concerning mechanisms of developmental change.

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Gaze following is a key component of human social cognition. Gaze following directs attention to areas of high information value and accelerates social, causal, and cultural learning. An issue for both robotic and infant learning is whose gaze to follow. The hypothesis tested in this study is that infants use information derived from an entity's interactions with other agents as evidence about whether that entity is a perceiver. A robot was programmed so that it could engage in communicative, imitative exchanges with an adult experimenter. Infants who saw the robot act in this social-communicative fashion were more likely to follow its line of regard than those without such experience. Infants use prior experience with the robot's interactions as evidence that the robot is a psychological agent that can see. Infants want to look at what the robot is seeing, and thus shift their visual attention to the external target.

The meaning, mechanism, and function of imitation in early infancy have been actively discussed since Meltzoff and Moore's (1977) report of facial and manual imitation by human neonates. Oostenbroek et al. (2016) claim to challenge the existence of early imitation and to counter all interpretations so far offered. Such claims, if true, would have implications for theories of social-cognitive development. Here we identify 11 flaws in Oostenbroek et al.'s experimental design that biased the results toward null effects. We requested and obtained the authors' raw data. Contrary to the authors' conclusions, new analyses reveal significant tongue-protrusion imitation at all four ages tested (1, 3, 6, and 9 weeks old). We explain how the authors missed this pattern and offer five recommendations for designing future experiments. Infant imitation raises fundamental issues about action representation, social learning, and brain-behavior relations. The debate about the origins and development of imitation reflects its importance to theories of developmental science.