I don't know if it's a girl and boy thing but looking at the above watercolour paintings that my Year 1 students did, it seems that it is. The ones on the left are the boys' and the right ones are the girls'. The girls tended to overdo it and layered too much colour and I can hardly see their farm house. At the end of the lesson, their table was a big mess with water and colour all over the table top. They were noisier as they painted. The boys, on the other hand, were quietly painting as they focused on what they were doing.
I actually told the students they could paint the farm house anywhere but the boys all decided to put theirs right in the middle while the girls put theirs in different places. A girl/boy thing? Maybe someone should try it out and see if they get the same results.
This lesson, by the way, was inspired by Vincent Van Gogh's Landscape painting below: