The functional approach to identification suggests that people with a particular motive tend to identify with groups that fulfill this motive. Thus, identification should be strongest when individual motives and group features match. The present paper explores the predictive power of this motive-feature match principle. Participants judged themselves on five motives (self-esteem, distinctiveness, belongingness, uncertainty reduction, and power), rated several groups on features relevant to fulfillment of these motives (e.g., the group's power as to the power motive), and indicated their identification with each group. Although the most predicted Motive x Feature interactions on identification emerged, the overall fit between data and predictions was moderate. The reductionist nature of the motive-feature match principle is discussed. Copyright # 2008 John Wiley & Sons, Ltd.Everyone belongs to numerous social groups, ranging from small groups, such as families or work teams, to large-scale social categories, such as nations, or ethnicity. Over and above this formal belongingness, some people even identify with some of their groups, that is, develop an inner bond to them. Identification, in turn, is relevant to behavior on behalf of one's group. For example, people who identify strongly versus weakly with a group exert more effort to achieve the goals of that group (e.g., Barreto & Ellemers, 2000;Ouwerkerk, De Gilder, & De Vries, 2000;Riketta, 2005;Worchel, Rothgerber, Day, Hart, & Butemeyer, 1998) are more likely to help other group members (Riketta & Van Dick, 2005;Tyler & Blader, 2001), are less likely to leave that group (Ellemers, Spears, & Doosje, 1997;Riketta, 2005), and discriminate more strongly against other groups (Aberson, Healy, & Romero, 2000).Given these behavioral implications of identification, it is important to know when and why people identify with groups. Previous research on the determinants of social identification has mainly focused on situational determinants, such as group status (Doosje, Spears, & Ellemers, 2002), self-esteem threat (Rubin & Hewstone, 1998), or uncertainty (Hogg, 2000. Although this research helps to predict what situations increase identification with a given group, it is not necessarily helpful when the goal is to predict who will identify most with that group. In this case, it is necessary to complement the prevailing situational, or social psychology, perspective on the determinants of identification by an individual difference, or personality psychology, perspective (e.g., Roccas, 2003).This has been done by the functional approach to social identification (e.g., Aharpour & Brown, 2002;Breakwell, 1993;Brewer, 1991;Correll & Park, 2005; e.g., Deaux, Reid, Mizrahi, & Cotting, 1999;Hogg & Abrams, 1990;Johnson et al., 2006;Sheldon & Bettencourt, 2002;Tajfel & Turner, 1986;Vignoles, Regalia, Manzi, Golledge, & Scabini, 2006). This approach rests on the premise that people identify with groups to the extent that these groups help them fulfill their individual moti...