  Let us return to the False Belief Task. It was noted earlier that children younger than 3-1/2 do not succeed in the classic paradigm. But in a recent study, Onishi and Baillargeon (2005) showed that infants as young as 13- to 15-months could succeed on a false belief task. In this study, babies were familiarized to a display of an adult placing a toy (a plastic watermelon slice) into one of two boxes and then reaching into the box as if to grasp it. The point of these familiarization trials was to indicate to the baby that reaching the toy was the adult’s goal. The toy was then moved from the box in which the adult had placed it to the other box. Although the baby always saw the toy move, and thus understood its new location, the adult did not always see the toy move; half the time, the adult’s view was blocked. The question is this: on the trials where the adult did not see the toy move to the new box—that is, when the adult had a false belief about the toy’s location—where do babies expect the adult to look for the toy? Looking time measures indicated that babies were surprised when the adult looked in the new box, even though babies knew it was the correct location. In contrast, on the trials in which adults saw the toy move to the new box, babies were surprised if adults did not look in the new location. At present there is no satisfactory account of why 3-year-olds fail the standard false belief task, given that 15-month-old babies seem to be able to attribute false beliefs to others. What else does the 3-year-old need, beyond what the 15-month-old already has, to succeed on the classic task? There are many candidate answers, but the Onishi and Baillargeon results have considerably changed the debate.