Young babies seem to do this as well. Remember that babies perk up and look longer when they see something new and stop looking if it's the same old thing.Suppose you show them the first sequence of events: the close ball followed by the faraway ball. Even though the image on their retinas has changed, they show no particular interest; they act as if the faraway ball is more of the same. However, they do perk up and pay attention when they see the big ball from far away, despite the fact that this time the size of the image on their retinas did not change. Babies, like us, seem able to go beyond the image on their retinas and perceive something about the real ball out there.