In a first study, teachers were asked to nominate the students who had either egoistic or altruistic charachteristics in their thinking and behavior in their everyday lives. The students chosen by the teachers completed the questionnaires concerning egoistic or altruistic thinking and behavior. The major findings were as follows; 1. Considerable discrepancies were found among the chosen students. 2. As for self-evaluation, the “egoistic students” considered themselves to be less egoistic than did the “altruistic” and “other students”. These results could be seen as reflecting the immaturity of the psycho-social skills of the egoistic students as compared to the altruistic students. The second study was carried out to prove the above assumption. Questionnaires about the social and psychological skill of the students were distributed to the teachers. After analysing the results, the assumption proved to he accurate. The results also indicated that it was more difficult for the teachers to discover the underlying causes behind the behaviors of “egoistic” students than those behind the “altruistic” students.