DELINQUENT BOYS WERE OBTAINED FROM THE DADE COUNTY CHILDREN'S HOME IN KENDALL, FLORIDA. TWELVE BLACK AND TWELVE WHITE BOYS WERE RANDOMLY SELECTED FROM AMONG THOSE COMMITTED TO AND ACTUALLY IN THE INSTITUTION DURING APRIL-JULY, 1967. TWELVE WHITE AND TWENTY BLACK BOYS WERE RANDOMLY SELECTED AS 'DEPENDENTS' FROM PARKWAY CHILDREN'S CENTER IN MIAMI, FLORIDA. THIRTY-TWO BLACK BOYS WITH NO KNOWN HISTORY OF DELINQUENCY OR DEPENDENCY WERE RANDOMLY SELECTED FROM THREE SIXTH-GRADE CLASSES, AND THIRTY-TWO WHITE BOYS WITH NO KNOWN HISTORY OF DELINQUENCY OR DEPENDENCY WERE RANDOMLY SELECTED FROM A POOLED LIST REPRESENTING SIX CLASSES OF SIXTH GRADERS AND THREE CLASSES OF FIFTH GRADERS. A TOTAL OF 120 SUBJECTS WERE USED AND RANDOMLY ASSIGNED BY RACE AND POPULATION TO THE 24 CELLS OF THE EXPERIMENT. ALL SUBJECTS WERE BETWEEN 10 AND 13 YEARS OF AGE. THE PRISONER'S DILEMMA GAME WAS MODIFIED SO AS TO STUDY AGGRESSION IN CHILDREN. THIS GAME PRESENTS A CONFLICT SITUATION WITHIN WHICH EACH OF TWO PLAYERS MUST SELECT ONE OF TWO STRATEGIES. THE FOUR POSSIBLE OUTCOMES ASSOCIATED WITH THE JOINT CHOICES OF THE TWO PLAYERS ARE ORDERED IN SUCH A WAY THAT A PARTIAL CONFLICT OF INTERESTS OCCURS. FOR THE PURPOSES OF THIS STUDY, THE GAME WAS MODIFIED BY GIVING AN OPTION TO THE SUBJECT AFTER EVERY SEVENTH ITERATION OF THE GAME OF TAKING $10 IN PLAY MONEY FROM THE OTHER PLAYER. SUBJECTS COULD NOT GAIN BY EXERCISING THIS AGGRESSIVE OPTION, AND WERE IN ALL CASES ASSIGNED A COST FOR UTILIZING THIS POWER. RESULTS INDICATED THAT BLACK SUBJECTS COOPERATED MORE AND WON LESS BY THEIR STRATEGY SELECTIONS. ALSO, THEY WERE MORE AGGRESSIVE WHEN THE 'OTHER' PLAYER DISPLAYED VULNERABILITY BY COOPERATING ON THE TRIAL PRECEDING THE OPTION THAN WERE WHITE SUBJECTS. THE TENDENCY OF BLACK SUBJECTS NOT TO DELAY GRATIFICATIONS, THEIR FEELINGS OF POWERLESSNESS, AND HIGH FEAR-OF-FAILURE ARE CONSIDERED THE PERSONALITY CHARACTERISTICS LIKELY TO BE ASSOCIATED WITH POOR POLICIES IN THE GAME. DATA FROM THE STUDY ARE PROVIDED, AND REFERENCES ARE GIVEN. (RCB)