What do we know about enrolling children in preschools before they begin formal schooling (which usually takes place at around 5 or 6 years of age)? children who attended any preschools before they began formal schooling were better off cognitively and socially compared to children who stayed at home. children who stayed at home before they began formal schooling show better emotional and cognitive competencies compared to children who went to preschools, even if these were high quality preschools. preschool education has no cognitive benefits for children. children who attended preschool before they began formal schooling were better off cognitively and socially compared to children who stayed at home.