Alberti, R. E., & Emmons, M. L. 1990 Your perfect right: A guide to assertive behavior (6th ed.). San Luis Obispo, California: Impact Publishers. 273-282. (Hanawa, T. 1999 Influence of interpersonal relations on emotional expression : Developmental changes in middle childhood. Japanese Journal of Educational Psychology, 47, 273-282.) Blos, P. 1962 On adolescence: A psychoanalytic interpretation. Oxford, England: Free Press of Buhrmester, D. 1996 Need fulfilment, interpersonal competence, and the developmental contexts of early adolescent friendship. In W. M. Bukowski, A. F. Newcomb, & W. W. Hartup (Eds.), The company they keep: Friendship in childhood and adolescence. New York: Cambridge University Press. Pp.158-185. Deluty, R. H. 1979 Children's action tendency scale: A self-report measure of aggressiveness and submissiveness in children. Journal of Counseling and Clinical Psychology, 47, 1061-1071. 180-190. (Enomoto, J. 1999 Socio-emotional development of friendship among adolescents: Activities with friends and the feeling for friends. Japanese Journal of Educational Psychology, 47, 180-190.) 146-155. (Fujii, K. 2001 The porcupine dilemma in adolescents'friendships. Japanese Journal of Educational Psychology, 49, 146-155.) Gay, M. L., Hollandsworth, J. G., & Galassi, J. P. 1975 An assertiveness inventory for adults. Journal of Counseling Psychology, 22, 340-344. Okamura, T. 1986 Developmental and therapeutic implication in Campus Encounter Group. Journal of Japanese Clinical Psychology, 4, 15-26.) struction, reliability and validation of Assertive Mind Scale. Japanese Journal of Humanistic Psychology, 16, 212-219.) 55-65. (Ochiai, Y., & Satoh, Y. 1996 The developmental change of friendship in adolescence. Japanese Journal of Educational Psychology, 44, 55-65.) Skatsche, R., & Kien, R. 1989 A comparison of factorial dimensions of assertion obtained from Anglo-American and German samples, with

special reference to Eysenck's personality variables. Personality and Individual Differences, 10, 219-228. Journal of Social Psychology, 8, 67-75.) Wilson, K. L., & Gallois, C. 1993 Assertion and its social context. London: Pergamon Press. 1998 The significance of facilitating adolescents'assertive ability and the issues involved in the measurement of assertiveness. Japanese Journal of Counseling Science, 31, 19-26.) 123-133. (Shibahashi, Y. 2001 Self-expression and expectation of friends'expression in adolescence. Japanese Journal of Developmental Psychology, 12, 123-133.) 67-75. (Wada, M. 1993 Same-sex friendship: Effects of sex and sex-role type. Japanese 1998 Development of interpersonal negotiation strategies and their relationship to sense of adaptation centering around sex differences in elementary and junior high school pupils. Japanese Journal of Educational Psychology, 46, 163-172.) Psychological Factors Related to Self-Expression and Expectation of Others'Expression in Adolescents'Friendship YUKO SHIBAHASHI (ATOM UNIVERSITY) JAPANESE JOURNAL OF EDUCATIONAL PSYCHOLOGY, 2004, 52, 12-23 The present study investigated psychological factors related to self-expression and expectation of friends' expression in adolescents'friendship. Junior and senior high school students (N=717) completed questionnaires. Factor analysis revealed 5 psychological factors:"a feeling of easiness toward friends", "concern for others/discreteness", "positive sense of value in frankness", "anxiety about self-expression skill", and "need for dominance". The results from multiple regression analysis showed the following:(1) "positive sense of value in frankness" was related to all self-expression and all expectations of friends'expression; (2)"anxiety about self-expression skill" was related negatively to expression of opinion and dissatisfaction about friends;(3) among senior high school students, "a feeling of easiness toward friend", was related to all self-expression;(4) among girls "concern for others/discreteness" was negatively related to expression of dissatisfaction, and among boys "need for dominance" related positively to it. Key Words: self-expression, reaction to other's expression, psychological factors, friendship, adolescents