They "learn", simply by being with others. That is a massive part of it. It's pretty subtle in Reception, this time last year, I thought "what is my son learning" but somehow, in that year, he grew up, became so much more confident and independent, he learnt to cooperate, he learnt to read, he learnt to just get on with life a bit... he was stimulated by being involved in a wide range fantastic school activities, not always aimed at the young ones, but they got involved too and gained so much from it.
He learnt to be able to speak up (in front of the whole school and parents) on numerous occasions. He is learning manners, tolerance and kindness.
It is not so much formal learning per se.... lots and lots of active stuff, gym, movement, music, cooking, as well as some more classroom based stuff. However, that said, by the end of the year he could read and write (from a starting point of nothing whatsoever at the beginning of reception).
Reception is the basis of their school life. A lot of it is play/activity, but boy do they take it all in!
He learnt more than I ever ever imagined he would in one short year