Within a multicultural society like the United States the psychological variability between ethnic groups is perceived as caused by differences rooted in culture (Shiraev & Boyd, 2001). Ethnicity may refer to a common cultural heritage of immigrants even in the distant past and maintained by ethnic organizations in music and dance. Ethnic identity can also be found in recent immigrants who have maintained a cultural relationship. However, ethnic group membership should not be confused with national identity since there are several or many ethnic groups in most nations today. Furthermore, the borders of ethnic groups may overlap with several nations. It is also possible to have several national groups within an ethnic category creating complexities in the concept of national identity.
Ethnicity is defined as the possession of a common cultural heritage based on geographical origin, but also possessing similar language, religion and historical traditions. Ethnicity may for many people be another word for race. However, racial identification provides little useful information about the cultural context. The student of cross-cultural psychology needs to know what factors link ethnicity to psychological differences between people for example as observed in emotional display, cognition or motivation. Phinney (1996) suggested that for ethnic identity to have value specific links must be established between cultural norms and values and behavior. A related issue is the relative strength of ethnic identity. If the role of ethnicity is weak in the individual it is not likely to have much influence on behavior. In turn the strength of ethnic identity probably depends on the relative acceptance of the ethnic minority within the dominant society and the route of acculturation.
A nation on the other hand refers to people who not only share a common origin along with history and language, but are unified as a political state and recognized as such. That might seem too narrow a definition for some peoples like the Kurds that meet all the criteria of nationhood, for example possess a relative independent territory in the north of Iraq, but have members of the Kurdish nationality living also in both Iran and Turkey. Likewise the Palestinian people are by all rights an autonomous nation, and would have become a nation state except by the imposed refugee status and occupation.
Countries have a culture based on their salient cultural history, their type of government, and economy. If the economic base does not meet minimal living requirements it produces a constant struggle for survival that influences the development of culture and the relative authoritarianism of governments. Increasingly because of globalization we observe the creation of cultural enclaves within sovereign countries. The Hispanic community in California, and the Vietnamese community in the U.S. created after the end of the war are but two examples from many that function within cultural enclaves.
Race is also considered an important social category for identity development although the physical characteristics thought by many people to be most important are of insignificant functional use in distinguishing between people on any meaningful psychological dimension. Rushton (1995) described race as based on a combination of heritable traits, but chiefly morphological characteristics that produce varying visual impressions. It is important to remember that in all races there are overlapping traits, for example the red hair often associated with the Irish is also present in Afghanistan, and even some Africans have red hair. The different physical appearance of race has occurred because of regional isolation and the forces of evolution, and really has little functional value except for arbitrary evaluations and categories (Brace, 2005). Race categorization has created considerable conceptual confusion with some researchers proposing as many as 37 different races. Although most people recognize the physical characteristics of race these morphological traits are as noted of little importance in behavior.
The most important consideration with respect to race categorization is to remember there is always more within race category variability on any genetic based trait including blood groups (and also in other physiological indicators) than differences between groups. It has been argued that race is more of a social construct than one based on biology, and developed from the natural human need to organize and categorize the world (Hirschfield, 1996). Although there is little biological differentiation on the basis of genetic and other biological distinctions, race is a powerful social construct with many very real negative consequences from prejudice and discrimination (Smedley & Smedley, 2005). It is culture that determines attitudes toward racial categories and therefore the meaning of racial constructs.