TWO EXPERIMENTS WERE CONDUCTED TO CLASSIFY AND TO CONDITION REWARD RESPONSIVENESS IN KINDERGARTEN CHILDREN. IN THE FIRST EXPERIMENT, 207 CHILDREN WITH A MEDIAN AGE OF 6.0 WERE CLASSIFIED ACCORDING TO THEIR RESPONSIVENESS TO A HIERARCHY OF REWARDS. AFTER TWO SESSIONS INVOLVING TWO-CHOICE INSTRUMENTAL CONDITIONING TASKS, 60 PERCENT OF THE CHILDREN WERE CLASSIFIED AS RESPONSIVE TO TANGIBLE REWARDS, 30 PERCENT AS RESPONSIVE TO SOCIAL APPROVAL (HALF OF WHICH WERE ALSO RESPONSIVE TO CONFIRMATION OF CORRECT RESPONSE), AND 10 PERCENT AS UNRESPONSIVE TO ANY OF THE THREE REWARDS. IN A THIRD SESSION, STIMULI WERE PAIRED TO CONDITION THE CHILDREN TO BECOME RESPONSIVE TO PREVIOUSLY NONREWARDING STIMULI. A FINAL SESSION WAS DEVOTED TO EVALUATION OF THE EFFECTIVENESS OF THE NEWLY ESTABLISHED REWARDS. DATA FROM THIS EXPERIMENT SHOWED THAT TANGIBLE REWARDS WERE MORE EFFECTIVE FOR KINDERGARTEN CHILDREN THAN WERE APPROVAL REWARDS AND THAT APPROVAL REWARDS AND CONFIRMATION OF CORRECT RESPONSES WERE EQUALLY EFFECTIVE AND POSITIVELY CORRELATED. IN THE SECOND EXPERIMENT, INVOLVING 90 KINDERGARTEN CHILDREN, IT WAS FOUND THAT A NEUTRAL WORD CAN BE CONDITIONED TO BECOME A REWARD STIMULUS AND THAT CONDITIONING IS STRENGTHENED BY A PERIOD OF REWARD DEPRIVATION. EVIDENCE WAS ALSO OBTAINED SHOWING THAT CHILDREN WHO ARE UNDERACHIEVERS TEND TO BE LOWER IN APPROVAL RESPONSIVENESS. THESE FINDINGS SUGGEST CERTAIN PROCEDURES TO BE EMPLOYED IN ESTABLISHING ACHIEVEMENT MOTIVATION AMONG KINDERGARTEN CHILDREN. DETAILED STATISTICS ARE REPORTED IN 24 TABLES. (JS)