Aged four: Zero to Hero In this series, the children were four years old. In the first episode, we considered whether you could already tell which of our children would become popular adults and which would be loners.

Even at this young age, the children were making decisions about each other, such as who they liked, who they thought were fun and who they wanted to as friends.

As the children interacted with others, the programme examined what part diet plays in childhood behaviour.

It also examined what makes a child a loner and asked if a sense of humour is likely to make a child more popular with their peers. We also saw how the children copied behaviour they saw on TV, particularly aggression.

Find out how the children communicated and made themselves understood in programme 2.

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