There is a concept in early childhood development called object permanence. Basically up to the age of two, little kids can’t get their heads around the idea that if something isn’t visible that it still exists.
This of course is why peek-a-boo is such a fun game to play with a thirteen-month-old. They are more able to believe that you keep appearing and disappearing, than they are that you continue to exist behind the hands that cover your face. Ah, the innocence of early youth.
Along those lines there is something I like to call Information Permanence. This is where a single mention of something sticks with you for a very long time, even though you were only exposed to it once. You know those songs that you can’t get out of your head? They call that an “ear worm.” Information Permanence is like a “brain worm,” but unlike the song that eventually leaves you alone, the “brain worm” can live in your noggin forever. This is a good thing – I will explain. […]