The recent anthropological literature contains both linear and non-linear models of acculturation. The non-linear model assumes that acculturation generates biculturality, that is, the addition of a new culture to the old one, whereas the linear model involves replacement of the old culture by a new one. Biculturality in the non-linear model gives freedom of choice, whereas the linear model implies culture conflict. The non-linear model stresses that acculturation processes are contingent upon social environment and therefore should be seen as a function of social reference groups. The linear model seems to take for granted the direct and entire embracement of the individual by a culture. This paper attempts to reinforce the three points of the non-linear mode--biculturality selectivity, and social contingency--while accepting what is valid in the linear model. As far as Issei (first-generation) immigrants from Japan and their Nisei children in Hawaii are concerned, social contingency attains full significance: the Japanese individual is trained morally as well as psychologically to be sensitive to the social setting. The native culture here facilitates acculturation, although the reverse is not true. This is demonstrated by analysis of the content of moral education textbooks used by Japanese language schools, expressed attitudes and opinions of school principals, and Nisei informants in various professional fields. (Author/JM)