Schools are children's main social centres, but they are not always experienced as sites for friendship. In between the joys of talking and playing are the volatile relationships, and the struggle for recognition or dominance.
It is hard for teachers, overstretched as they are, to detect the everyday turbulence of the emotional life of the groups.
Pupils often use the phrase "being picked on". The atmosphere is catching, and while being quite clear about guilt and responsibility, pupils do not subscribe to the typologies of "bullies" or "victims".
Girls are often targets for teasing. Most of this emotional life is kept fairly hidden, but it is a central part of school life.
"Boys are the most thing that gets on my nerves. Because they take the Mickey out of me and say "Moo. Moo," and everything."
Grace, aged 8
"If only people wouldn't come up to me and start kicking me and that. When they start, if I catch them, I just get up and swing them round me - because I get annoyed with them."
"The teacher says, 'I expect you're about as bad as each other'" Ethan, 8
There are more subtle ways of being hurt. The changing of friends or the refusal to play with each other can cause mayhem to relationships until children do not know whom to trust.
"I just feel a bit upset. And say, 'why can't I play?' and they just say, 'well, you can't play, okay?' And shout. I get a bit upset."
The children's names have been changed. Cedric Cullingford is professor of education at Huddersfield university. His book, The Best Years of their Lives? Pupils' Experience of School is published by Kogan Page