It lends support to plans to widen access to childcare and set up integrated services that bring together early education with childcare and family support.
The Effective Provision of Pre-School Education project, led by Kathy Sylva at Oxford University has followed more than 3,000 children from age three to seven.
It found that what parents did made more difference to their chidren's development than how well their mother was educated. Children whose parents spent time reading or painting with them, or taught them the alphabet, numbers and songs were more independent, co-operative and sociable.
The study compared the impact of six types of pre-school. It found children made more intellectual progress in integrated centres and nurseries than in other types of setting.
But centres run by highly-qualified teachers - more common in nurseries - were best. Social skills also improved most in integrated centres or nurseries. The study also found that the best pre-schools combined teaching and play.
The findings come after End Child Poverty, a coalition of public agencies, published a report this week revealing that an attainment gap between poor and better-off children is evident at 22 months and widens as a child gets older.