Studies to investigate the effects of day care on cognitive development produced some contradictory results. A study of 146 eight-year-old Swedish children by Broberg (1997) showed that those who had attended day nurseries as infants consistently produced higher results in tests of verbal and mathematical ability than children who had been raised by childminders or at home. However, a study of 1000 American 3-4 year old children found that children who attended day care since before they were one had the lowest vocabulary scores regardless of their social class, however this analogy only applied to white children. Again, the variation ...