Although previous research found that many factors facilitate in-group identification, past studies did not consider the interactive effects of intra-group and inter-group factors (e.g., ingroup social values). Therefore, my first purpose in this doctoral study was to explain in-group identification change from the perspective of comparative change of categories' meaningfulness. The questionnaire survey and The experiment supported the prediction that interaction with other in-group members and a high level of value synergistically promoted in-group identification and suggested a high level of context-dependent meaningfulness of inter-group factors. My second purpose was to develop this approach on a basis of multi-level infl uence processes among individual, interpersonal, group, social, and cultural factors. The minimal group paradigm and the longitudinal questionnaire survey focused on the effect of independent and interdependent self-construal, as an individual factor implying cultural-level differences, which present a threat to self-esteem from a personal task-relevant stress or interpersonal stress on in-group favoritism. For buffering threats to self-esteem, independents identify more than interdependents with the in-group. Moreover, the questionnaire survey allowed an examination of the effect of the in-group's social value as a sociallevel factor. The results showed that independents, who reported more threats to their self-esteem, identifi ed more with the in-group only when the ingroup's value was high. Interdependents showed less in-group identification, regardless of the ingroup's value. The results also suggested that such a multi-level approach enables a possible expansion from individual to cultural factors.