PREVIOUS RESEARCH SUGGESTED THAT YOUNG CHILDREN DEAL WITH CONCEPTS IN WAYS THAT ARE UNEXPECTEDLY DIFFERENT FROM ADULT PERFORMANCE. THE PRESENT STUDY INVESTIGATED THE POSSIBILITY THAT THESE RESULTS WERE DUE TO A SYSTEMATIC TENDENCY FOR YOUNG SS TO HAVE OVERLY NARROW CONCEPTS. RESULTS INDICATE A SIGNIFICANT TENDENCY FOR OVERDISCRIMINATION OF CONCEPT INSTANCES AS A FUNCTION OF AGE. WHILE THIS TENDENCY USUALLY LED TO POORER PERFORMANCE ON THE PART OF YOUNGER SS, CASES WERE FOUND WHERE NARROW CONCEPTUALIZATIONS WERE BENEFICIAL, AND 6-YR-OLDS ACTUALLY MADE SIGNIFICANTLY FEWER ERRORS THAN ADULTS. (PsycINFO Database Record (c) 2006 APA, all rights reserved)