Scottish three-year-olds have a wider vocabulary and better understanding of colours, numbers and shapes than those elsewhere in the UK, a study has shown.
The research found Scottish children were good with colours and shapes
Researchers from the University of London are tracking the development of more than 15,000 children.
Examining vocabulary, they found that three year-olds in Scotland were three months ahead of their counterparts in England, Wales and Northern Ireland.
Scots children were ahead by two months when "school readiness" was examined.
This gauged their understanding of not only colours, numbers and shapes but letters, counting and comparisons.
More than 12,000 children across the UK were involved in the vocabulary section and 11,500 for the school readiness tests.
More than 1,250 children in Scotland took part in each assessment.
The assessments were conducted on behalf of the Centre for Longitudinal Studies, which is based at London University's Institute of Education.
They form part of the Millennium Cohort Study (MCS), which is tracking more than 15,500 children born between 2000 and 2003.
Professor Heather Joshi, the centre's director, said further analysis would have to be carried out in order to establish why Scottish three-year-olds were outperforming the rest of the UK.
"Various factors may help to explain this", she said.
"There are fewer large families in Scotland and there were relatively more prosperous families in our sample.
"There is also less ethnic diversity, but a full investigation remains to be completed."
The research also found that more Scots fathers read to their children and four in five Scots parents in the survey thought their home area was either an excellent or good one in which to bring up children.
Scottish mothers were also more likely to have jobs (62%) than mothers in other UK countries and were more likely to to have rules in place to govern their child's behaviour.
Across the UK, the report found that many children from disadvantaged backgrounds were educationally already up to a year behind more privileged youngsters by the age of three.
The vocabulary scores showed that the sons and daughters of graduates were 10 months ahead of those with the least-educated parents.
There was a 12-month difference in the school readiness tests.
The equivalent gaps for children in families living above and below the poverty line used by the researchers were five months for vocabulary and 10 months for school readiness.
Prof Shirley Dex, co-author of the report, told the BBC's Good Morning Scotland programme: "If you have two natural parents in England, Wales and Northern Ireland, in terms of development, the children are four months ahead of the average child.
"In Scotland that would be six months."
But she added that this would also mean the child would be further behind in Scotland if it was from a disadvantaged background.
The report also found that, on average, girls were three months ahead of boys on both measures.
The assessments also highlighted marked ethnic differences.
A quarter of the black Caribbean and black African children who took the school readiness assessment were delayed in their development, compared with only 4% of white children.