IN THE STUDY OF EDUCATIONALLY DISADVANTAGED PRESCHOOL CHILDREN, 160 PREDOMINANTLY NEGRO CHILDREN 3 1/2 TO 4 1/2 YEARS OF AGE WERE PRETESTED ON A BATTERY CONSISTING OF A LANGUAGE TEST, DESIGNED TO EXPLORE THE CHILDREN'S FANTASY BEHAVIOR, AND TWO BRIEF INTELLIGENCE TESTS. CHILDREN WERE ASSIGNED TO NURSERY AND NONNURSERY GROUPS ON THE BASIS OF LANGUAGE, AGE, AND SEX. THE NURSERY CHILDREN HAD 6 WEEKS OF PRESCHOOL EXPERIENCE. ALL THE MOTHERS PARTICIPATING IN THE EXPERIMENT WERE NEGROES. POST-TESTING WAS CARRIED OUT 4 WEEKS AFTER THE SUMMER NURSERY WAS COMPLETED, AND INVOLVED AMINISTRATION OF THE ENTIRE BATTERY USED IN PRETESTING. HALF OF THE CHILDREN WOULD RECEIVE FOLLOW-UP EXPERIENCE FROM AN EDUCATOR AND A SOCIAL WORKER, WHILE THE OTHER HALF OF THE CHILDREN WOULD NOT RECEIVE SUCH FOLLOW-UP EXPERIENCE. THE INITIAL UNCOOPERATIVENESS OF SOME MOTHERS HAD A DEFINITE EFFECT ON THE CHILDREN'S TEST PERFORMANCE. MANY WERE EXTREMELY INTIMIDATED AND OVERWHELMED IN THEIR FIRST ENCOUNTER. THE MOTHER'S ATTITUDE TOWARD THE SITUATION ALSO INFLUENCED MOTHER-CHILD INTERACTIONS. THE BASIC DIFFERENCES BETWEEN THE MOTHERS IN THE STUDY AND OTHER MOTHERS SUGGEST THAT DIFFERENCES IN THE MATERNAL BEHAVIOR BETWEEN MIDDLE AND LOWER-CLASS MOTHERS HAD TO BE EXAMINED NOT ONLY IN THE LIGHT OF CLASS DIFFERENCES, BUT ALSO IN TERMS OF DIFFERENCES IN THE MEANING OF THE EXPERIMENTAL SITUATION TO THE SUBJECT. THE SAMPLING RESTRICTIONS ON THE NUMBER OF VARIABLES WHICH COULD BE SYSTEMATICALLY STUDIED EMPHASIZED THE IMPORTANCE OF KNOWING FOR FUTURE RESEARCH WHICH VARIABLES WERE ESSENTIAL AND WHICH WERE RELATIVELY UNIMPORTANT FOR A POPULATION OF THIS KIND. IN THE FUTURE IT WOULD SEEM NECESSARY TO USE VARIABLES SUCH AS A CHILD'S REACTION TO THE INITIAL TEST SITUATION RATHER THAN LANGUAGE AGE, FOR PURPOSES OF STRATIFICATION. THIS PAPER WAS PRESENTD AT THE ANNUAL MEETING OF THE AMERICAN EDUCATIONAL RESEARCH ASSOCIATION (CHICAGO, FEBRUARY 12, 1965).