Pupils who attend ethnically diverse schools develop higher levels of self-esteem and are less likely to suffer from bullying, according to researchers.
Children as young as five are already aware of issues around racial integration and segregation, a study has revealed for the first time.
But all pupils, regardless of their background, benefit from going to schools where at least one in five children comes from an ethnic minority, said Rupert Brown, professor of social psychology at Sussex University.
Clear social benefits of ethnically diverse schools mean pupils integrate better and get on with peers from different backgrounds, he said.
"Our findings add to a growing body of evidence suggesting that the more contact children have with other ethnic groups, the more cross-group friendships they will have and the less prejudiced they will be," said Professor Brown.
"We found that when the proportion of ethnic minority children in schools is at least 20 per cent, both ethnic minority children and majority children tended to have higher self-esteem . and there were fewer problems with peer relationships such as bullying."
His findings come from a year-long study at 20 schools in Sussex and Kent that had between 2 per cent and 63 per cent of children from ethnic minorities.
Interviews with children showed they wanted to keep their ethnic identity in terms of language and religion, but were also keen to adopt mainstream practices as far as possible. This tendency was clear in children as young as five, but became more marked by the time children reached eight and above, the research found.
Children with this integrationist attitude experienced quick improvements in their self-esteem and how well they were accepted by their white English classmates.
But there was also evidence that balancing the demands of two cultures could cause problems for these pupils, who were more likely to be "teary and show other signs of social anxiety".
These children also reported more cases of racial discrimination, although adverse effects were reduced in more ethnically diverse schools, the study found.
The conclusions follow the findings of research by Lancaster University, released earlier in the year, which said that mono-cultural white or Asian schools should be avoided as they could damage community relations, perpetuate extremist attitudes among white people and fail to prepare Asian Muslims for prejudice that they might be exposed to later.
Professor Brown's report, co-written by Adam Rutland and Charles Watters, both of Kent University, also appears to cast doubt on the wisdom of expanding the numbers of faith schools, which tend to segregate children along religious and cultural lines.
Ed Balls, the Schools Secretary, has said he is not encouraging an increase in the number of faith schools and that decisions should be made locally. But a government document released last year, Faith in the System, praised the schools for contributing towards community cohesion and appeared to pave the way for expansion.
`Identities in Transition: a longitudinal study of immigrant children', funded by the Economic and Social Research Council.