THREE- AND 4-YEAR-OLDS WERE GIVEN VERBAL LEARNING PRETRAINING TO DETERMINE ITS EFFECT UPON THE PERFORMANCE OF REVERSAL AND NONREVERSAL SHIFT DISCRIMINATION TASKS. THE EXPERIMENTAL TASK WAS THE CLASSICAL REVERSAL-NONREVERSAL SHIFT PARADIGM. THE 96 PRE-SCHOOLERS, PRIMARILY FROM THE PENNSYLVANIA STATE UNIVERSITY NURSERY SCHOOL, WERE DIVIDED INTO 4 GROUPS, 3 OF WHICH RECEIVED PRETRAINING AND 1 OF WHICH DID NOT. THE DATA COLLECTED WERE TREATED BY ANALYSIS OF VARIANCE. RESULTS SHOWED THAT THE REVERSAL SHIFT WAS QUICKER AND EASIER FOR THE CHILDREN THAN THE NONREVERSAL. A SECOND EXPERIMENT USING 48 CHILDREN CONFIRMED THESE FINDINGS ALTHOUGH PREVIOUS EXPERIMENTAL RESULTS AND VERBAL MEDIATION THEORY HAD INDICATED THAT THE NONREVERSAL SHIFT WAS EASIER FOR THE CHILDREN. OTHER VARIABLES SUCH AS THE CHILDREN'S PROFICIENCY IN VERBAL MEDIATING RESPONSES MAY HAVE CAUSED THE PRESENT STUDY RESULTS, BUT THE RELATIONSHIP BETWEEN VERBAL LABELING PRETRAINING AND TYPE OF SHIFT REMAINS INCONCLUSIVE. FURTHER STUDIES SHOULD DETERMINE WAYS TO IDENTIFY AND ISOLATE VARIABLES WHICH AFFECT THE ABILITY OF YOUNGSTERS TO PERFORM EXPERIMENTAL TASKS. THIS DOCUMENT WAS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY AT PENNSYLVANIA STATE UNIVERSITY. (MS)