Investigating the social environment of the A-not-B search task.

Controversy exists concerning the origins of object permanence, with different measures suggesting different conclusions. Looking measures have been interpreted as evidence for early understanding (Baillargeon, 1987, Developmental Psychology, 23:655), while Piaget (The construction of reality in the child, 1954) interpreted perseverative reaching behaviour on his AB search task to be indicative of limited understanding. However, looking measures are often reported to be an unreliable index of infant expectation (Haith, 1998, Infant Behaviour and Development, 21:167) and reaching behaviour has been explained by many alternative processes (e.g. Smith et al., 1999, Psychological Review, 106:235; Topál et al., 2008, Science, 321:1831). We aimed to investigate whether social looking (Dunn & Bremner, 2017, Developmental Science, 20:e12452; Walden et al., 2007, Developmental Science, 10:654) can be used as a valid measure of infant expectation of object location during the Piagetian AB search task. Furthermore, we aimed to test the social accounts of perseverative reaching by investigating how the direction of experimenter gaze would affect infant search and social behaviour. Infant search and social behaviour was compared on B trials across three different conditions, namely experimenter gaze to midline, location A and location B. Search performance significantly improved when the experimenter looked to location B. Infant social looking indicated that infants expect the object to be found in the location in which they search and are actively seeking information about object location from the experimenter. We conclude that social looking is a valid index of infant expectation that has provided support for the importance of the social environment on the AB search task. This casts doubt on the potential for this task to provide information related to the development of object permanence in infancy.