NPR Science: Apes May Be More Like Us Than We Thought. By Alva Noë.
“Suppose I take the candy from the cabinet where you left it and put it someplace else. Where will you look for it when you get home?
Children younger than 5 will rarely get this right. When questioned, they will say, mistakenly, that you will look for the candy at its new location. […] If you measure not what they say, but what they do, in particular, where they look, it turns out that they are able to anticipate that you will look for the candy where you mistakenly believe it still is.
We now know the same is true of apes.”