Dr Sam Wass

The four-year-olds make their first moves towards gaining independence, discovering all the ups and downs of making friends and social interaction.

The children are back after a fortnight apart, but this time they are joined by some new friendly faces.

Drawing on the experience of their first year at school, these five-year-old children have expanded their vocabularies, are learning how to make friends, and are beginning to get to grips with wider concepts like morality and identity.

The five-year-olds come back together after two weeks apart and are joined by some new playmates. Time has made the heart grow fonder, as Alfie and his best friend Emily reunite.

A documentary crew follows young children aged 4, 5 and 6 out of the playroom and into the great outdoors. This time, the emphasis is on sibling relationships and it is the first time such an experiment has taken place in the UK.

Articulate and sophisticated, the six-year-olds have had the benefit of two years at school and are beginning to focus much more on their own identity. Race, religion, love, and death are all up for discussion.