A PRESCHOOL EDUCATIONAL PROGRAM WAS DEVELOPED IN WHICH THE ONLY TEACHER FOR THE CHILD IS HIS MOTHER. IT WAS HYPOTHESIZED THAT MOTHERS OF LOW SOCIOECONOMIC AND EDUCATIONAL LEVEL CAN CONTRIBUTE MATERIALLY, WITH MINIMAL BUT PROPER TRAINING, TO THE INTELLECTUAL AND LINGUISTIC DEVELOPMENT OF THEIR CHILDREN. THE TRAINING PROGRAM FOR THE MOTHERS CONSISTED OF 11 WEEKLY 2-HOUR SESSIONS IN WHICH EXPERIENCED PRESCHOOL TEACHERS WORKED WITH THE MOTHERS IN PREPARING SIMPLE, INEXPENSIVE PROJECTS AND MATERIALS TO BE USED WITH THE CHILD, AND INSTRUCTED THE MOTHERS IN HOW TO USE THE MATERIALS. THESE MOTHERS WERE PAID $3.00 PER SESSION. THIRTY CHILDREN WERE INVOLVED, RANGING IN AGE FROM 39 MONTHS TO 51 MONTHS AT THE TIME THE 12-WEEK PROGRAM BEGAN. THE CHILDREN, HALF OF WHOM WERE TO BE INSTRUCTED BY THEIR MOTHERS AND HALF OF WHOM WERE TO RECEIVE NO COMPENSATORY INSTRUCTION, WERE INITIALLY MATCHED ON SEX AND INTELLIGENCE QUOTIENT. ALL OF THE CHILDREN RECEIVED PRE- AND POSTTESTS ON THE STANFORD-BINET, WHICH MEASURES INTELLIGENCE LEVEL, AND ON THE ITPA, WHICH MEASURES LANGUAGE ABILITY. THE TEST RESULTS SHOWED THAT THE INSTRUCTED CHILDREN GAINED SIGNIFICANTLY MORE IN INTELLIGENCE LEVEL OVER THE 12 WEEKS THAN DID THE CONTROL CHILDREN AND ALSO IMPROVED IN LINGUISTIC FUNCTIONING MORE THAN DID THE CONTROL GROUP. THE HYPOTHESIS WAS DEMONSTRATED TO BE ACCURATE, BUT IS CANNOT YET BE CONCLUDED WHETHER OR NOT THE GAINS CAN BE SUSTAINED OVER THE FUTURE. (WD)