IT APPEARS, HOWEVER, THAT DELINQUENTS TEND, INDIVIDUALLY AS WELL AS IN GROUPS, TO OVERESTIMATE THEIR POSSIBILITIES OF SUCCESS EVEN THOUGH THEY HAVE BEEN ABLE TO TEST THEIR COMPETENCE DURING A LEARNING PERIOD. BY CHOOSING A LEVEL OF PERFORMANCE WHICH THEY CAN NOT REACH, EVERYTHING APPEARS AS IF THEY WANTED TO FORCE THEIR LUCK. THIS DISCREPANCY BETWEEN THEIR LEVEL OF ASPIRATION AND THEIR LEVEL OF COMPETENCE IS PROBABLY ONE OF THE CHARACTERISTICS OF THEIR BEHAVIOR. HOWEVER, AN ADDITIONAL STUDY SHOWS THAT, AT AN INDIVIDUAL LEVEL, THESE DELINQUENT BOYS MAY MODIFY THEIR BEHAVIOR IN THE DIRECTION OF A BETTER ADJUSTMENT, BUT THAT THIS TENDENCY DISAPPEARS AFTER A GROUP DISCUSSION INTENDED TO LEAD TO A COMMON DECISION. (AUTHOR ABSTRACT) --IN FRENCH. SUMMARY IN ENGLISH...ELW