Theory of mind
Katy has always had an impressive memory for details, and a great vocabulary. Once (when she was just 5) Owen asked her how she could remember so many words, and she explained her own model of how her memory worked: all the words were stored on shelves in her brain, and a little eye went along the shelves seeking the word it needed at any one time. My memory, by contrast, is rather less than impressive, and the rest of the family often sigh in exasperation "Your memory is like a sieve". This evening she was trying to make sure I would remember her instruction about something, and suggested "Make the thought so wide that it can't get through the holes in the sieve."