A dog chasing a ball will look for it if it disappears behind something. Remember aspects of the object as the same as a previous object or as coming from a new object. The task is basically the same whether the stimuli are visual, tactile, auditory or olfactory or a combination.
Success involves recognizing repeated instances of the same object or the same kind of object.
Present machine learning schemes are more suited to recognizing kinds of objects than for recognizing individual objects. Both are needed. At least some of these structures are independent of the sensory modality. The child is predisposed to name kinds of entities and to expect that the objects of a kind that is recognized by superficial properties will have additional properties in common. For example, adults call some objects lemons, and all lemons turn out to have similar taste and to have similar seeds.