Why do children do this?

Today there has been an exasperating breakthrough, one of many. I suppose I can expect more.

The first time I really noticed these exasperating breakthroughs was the 'point to the nose' issue. Since he was tiny and I was playing with him on the changing mat I have pointed to various bits of him and named them - nose, eyes, hair, knee... I used to point to his nose and say 'nose', then point to my nose and say 'nose' etc. As he grew a little older I would ask him to point to various bits - including his nose. I got The Look that said very clearly that he knew where his nose was, I knew he knew where his nose was and that he was not going to be bothered going through that rigmarole, thank you so much.

Then he watched 'In The Night Garden' and when the Tombliboos (sp?) touched their noses, so did little bear. I was so pleased that he confirmed that he knew where his nose was, but why then!

Numbers are another case in point. I have sung counting songs to him, counted stairs and steps since he was born, counted toes, counted buttons - tried to be a stimulating mum. He could count before he watched the Numberjacks, but once he saw them that was when he really got going. Everything was counted (probably - on, doo, ee, door, pav, seeeees, pah, aaat, noine, DEN! I have no idea what has happened to seven).

And today little bear was sort of singing along with the Cubeez, or at least vaguely tuneful syllables were coming out when the Cubeez were singing. I have sung to him since he was born, and I have been singing along to CDs and tv to try and encourage him to join in, to no avail. When other children were singing together he just watched. However now that he has watched the Cubeez...

He has a lovely voice.