Prior to 8 months, infants do not search for an object when someone hides it from them. After 8 months, they begin to search and do so accurately provided the object is hidden in the same place each time. If the object is hidden in a new location, infants of less than 12 months perseverate in searching in the original location. Following 12 months of age, the error recurs if the task is made more complex. For instance, if an object is hidden in a box, the box is moved under a cover where the object is tipped out, and the box is moved back to its original location, infants will search only in the box. Piaget takes the onset of search at 8 months as evidence for the beginnings of object permanence, and uses the errors that occur up to 24 months as evidence for the limitations in its early forms.
See A-not-B task/error, Object identity, Object permanence, Search errors in infancy