THE PURPOSE OF THIS STUDY WAS TO DETERMINE THE RELATIVE INFLUENCE OF FIVE VARIABLES (INITIAL INSTRUCTIONS, REWARD, LETTER SIZE, TYPE OF WARM-UP, AND FEEDBACK) ON KINDERGARTEN CHILDREN'S PERFORMANCE OF A LETTER DISCRIMINATION TASK. IT HAS BEEN ARGUED THAT ATTENTION IS THE KEY FACTOR IN LETTER DISCRIMINATION. THE PRESENT STUDY PROPOSES THAT A PRECONDITION TO SUCCESS BY CHILDREN IN LETTER DISCRIMINATION IS HAVING AN ADEQUATE CONCEPT OF "SAMENESS." THAT IS, IF THE CHILD IS NOT AWARE OF WHAT THE EXPERIMENTER MEANS BY THE WORDS "SAME" AND "DIFFERENT" IN A DISCRIMINATION TASK, ATTENTION IS ALMOST IRRELEVANT. EIGHTY KINDERGARTEN PUPILS WERE DIVIDED INTO FIVE TEST CONDITIONS TO PERFORM THE DISCRIMINATION TASK. THE TASK METHODOLOGY CONSISTED OF PRESENTING A SINGLE LETTER ON THE LEFT SIDE OF A PIECE OF PAPER AND FOUR ROWS OF TEN LETTERS ON THE RIGHT SIDE. AMONG THESE 40 LETTERS WERE FIVE LETTERS IDENTICAL TO THE SINGLE LETTER, FIVE MOST LIKELY TO BE CONFUSED WITH THE SINGLE LETTER, AND 30 ADDITIONAL LETTERS. THE CHILD WAS ASKED TO IDENTIFY THE LETTERS IN THE FOUR ROWS THAT MATCHED THE SINGLE LETTER. THIS METHOD REPRESENTED TEST CONDITION ONE. THE REMAINING FOUR CONDITIONS WERE ESSENTIALLY THE SAME AS CONDITION ONE EXCEPT FOR VARIATIONS IN SCORING INSTRUCTION GIVEN (CONDITION TWO), USE OF REWARD (CONDITIONS THREE AND FIVE), AND TYPE OF WARM-UP (CONDITION FOUR). THE RESULTS SHOWED THAT NEITHER VARIATION OF LETTER SIZE NOR SCORING INSTRUCTIONS HAD AN EFFECT ON PUPIL PERFORMANCE. THE FEEDBACK WAS EFFECTIVE, FOR IT HELPED THE PUPIL DEVELOP THE CONCEPT OF "SAMENESS" NECESSARY TO MAKE THE DISCRIMINATION. (WD)