Minding the gap: a sex difference in young infants’ mental rotation through thirty degrees of arc

Mental rotation (MR) is an important feature of spatial cognition invoking mental imagery of an object's appearance when viewed from a new orientation. Prior studies have revealed evidence of MR in infants, including a sex difference similar to that detected in older populations. Some of these studies used visual habituation methods whereby infants were familiarized with an object rotating through a 240° angle, followed by test trials showing either the habituation object or a mirror image object rotating through the previously unseen 120° angle. Significantly longer looking at either of these objects was taken to reflect infants' ability to