FIGURE 9.4 Testing Object Permanence in Babies How can you test object permanence in infants who are too young to reach for a hidden object? Three-and-a-half-month-old infants initially watched a possible event: The short carrot passes from one side of the panel to the other without appearing in the window. In the impossible event, the tall carrot does the same. Because the infants are surprised and look longer at the impossible event, Baillargeon and DeVos (1991) concluded that the infants had formed a mental representation of the existence, height, and path of each carrot as it moved behind the panel—the essence of object permanence (Baillargeon, 2004).