This research investigated infants’ scanning of a talking, socially engaging face. Three- to four-month-olds looked equally at the mouth and eyes whereas 9-month-olds attended more to the eyes than mouth. These findings shed light on information infants’ seek from dynamic face stimuli.

A growing number of sex differences in infant behavior have been reported over the last 10 years. One task on which sex differences have been observed reliably is the event-mapping task. In this task, infants view an occlusion event involving 1 or 2 objects, the occluder is removed, and then infants see 1 object sitting on the platform. When the occlusion sequence is complex (i.e., involves paths of motion that change direction when occluded), boys are more likely than girls to detect an inconsistency between a 2-object occlusion event and a 1-object display. The current research used eye-tracking technology to investigate the specific cognitive processes that underlie these sex differences. Three experiments were conducted with 2 age groups of infants with mean ages of 9 months and 4 months. Infants saw a ball–box (2-object) or ball–ball (1-object) occlusion event followed by a 1-ball display; visual scanning of the occlusion event and the 1-ball display was recorded. In the older age group, boys were more likely than girls to visually track the objects through occlusion; they were also more likely to detect an inconsistency between the ball–box event and the 1-ball display (i.e., they visually searched for the missing box). In addition, tracking of the objects through occlusion was related to infants' scanning of the 1-ball display. In the younger age group, both boys and girls failed to track the objects through occlusion and to detect an inconsistency between the ball–box event and the 1–ball display. These results suggest that infants' capacity to track objects through occlusion facilitates extraction of the structure of the initial event (i.e., the number of distinct objects involved), that infants can map onto the final display, and that sex differences in this ability emerge between 4 and 9 months. Possible explanations for how the structure of an occlusion event is extracted and mapped onto a subsequent nonocclusion display are considered.