Observing others’ joint attention increases 9-month-old infants’ object encoding

In direct interactions with others, 9-month-old infants' learning about objects is facilitated when the interaction partner addresses the infant through eye contact before looking toward an object. In this study we investigated whether similar factors promote infants' observational learning from third-party interactions. In Experiment 1, 9-month-old typically developing infants from mixed socioeconomic backgrounds from urban Germany (N = 32, 13 female) were presented with four types of videos showing one object and two adults. The scenarios varied systematically regarding the eye contact between the adults (eye contact or no eye contact), and the adults' object-directed gaze (looking toward or away from the object). To assess infants' encoding performance we measured their looking times when seeing the familiarized object subsequently next to a novel object, interpreting an enhanced novelty preference as reversely indicating greater encoding of the familiarized object. Infants showed an increased novelty preference, but only after observing a joint attentional setting during which two adults attended to the familiarized object together (following eye contact). In Experiment 2, we found an identical pattern of results in a matched first-party design in which 9-month-old infants (N = 32, 16 female) were directly addressed by one single adult on screen. Infants' encoding was only enhanced when the adult made eye contact with the infant before looking at an object. Together, this suggests that the capacity to learn through observing others' interactions emerges already in the first postnatal year, and that it may depend on similar factors as infants' learning through direct social engagement