自 1965 年移民法案通過之後，美國開始大量接受來自世界各國的移民，而做為移民入口之一的加州，州內少數族裔人口比例逐年上昇，使白人在2000 年人口普查中人口比例首次低於50%，如此多族裔的人口組合不禁使人擔心是否易於發生族裔衝突，進而危害美國社會的穩定。本文根據 Social Identity Theory 探討社會網絡（social context）對於族裔認同（ethnic identity）的影響，認為多元族裔的社會網絡（如校園）應可增進各族裔的相互瞭解、降低族裔認同，進而營造和平共處的氣氛。在分析1996、1998 年針對UCLA大學生的連續調查後，證實學生個人社會網絡的組成，如語言使用、居住環境、交友族裔組合與宿舍族裔組合等，對其族裔認同的強度有顯著的影響。本文發現學生如結交同族裔朋友會相對增加對該族裔的認同，而結交其他族裔朋友有助於降低族裔認同，但對黑人和白人學生來說，結交其他族裔朋友對降低他們的族裔認同並沒有顯著影響。因此，雖然美國致力以政治力保證校園的族裔多元性，給予各族裔在校園中公平的代表性，鼓吹「美國認同」以取代各族裔的族裔認同，希望減低族裔衝突的可能性，但研究發現學生往往在校園中自我篩選社會網絡、交往對象，其影響力超乎於外在營造出的多元環境，成為維持學生族群認同強度的基本因素。

The United States has been accepting large numbers of immigrants from Asia and Latin America after the passage of new immigration laws in the 1960’s. California, as one of the major immigration gateways to the U.S., has a rapid growing non-white population in which whites are no longer in majority. The controversy has grown out concerning whether ethnic diversity will help create a harmonious society, or whether it brings the U. S. into a state of ethnic conflicts. This paper raises an important question in time of increasing diversity: what determines the effects of diversity in a campus environment upon ethnic assimilation or polarization? The data of a panel study of UCLA undergraduates show that one’s social context significantly influences his strength of ethnic identity. The pre-entry identity is determined by immigration background, language use, and the ethnic composition of high school friends. Yet, the strength of ethnic identity in college is further supported by the numbers of ingroup and outgroup college friends. Ingroup friendship helps increase the strengths of ethnic identity in all groups. Outgroup friendship only decreases the ethnic identities in Asians and Latinos, but has no significant effects on whites and blacks. My results confirm the hypothesis that campus context does have additional effects on students’strength of ethnic identity, and also suggest that people would self-select their social contexts to maintain or strengthen their ethnic identities. This may bring a warning to those who believe in the fact that more intergroup contact can ease identity barrier. Intergroup contact may be able to erase the ethnic identities of new immigrants, but not those of whites and blacks.

美國研究;族裔認同;族群認同;社會網絡;社會認同理論; 多元族裔校園

American study; ethnic identity; social context; Social Identity Theory; multi-ethnic campus