Social identity is the part of a person's self-concept that derives from membership in groups that are important to them (Tajfel & Turner, 1986). Research shows that people are motivated to have a positive social identity and that when they feel connected to a social group, their self-esteem is higher and they feel safe and accepted (Hogg & Abrams, 1990; Mio, Barker, & Tumambing, 2012). In contrast, when people feel excluded, rejected, or ignored by others, they experience hurt feelings and are likely to withdraw from the interaction (Williams, 2001). When people consider how another individual is affected by her or his social situation, they are more likely to feel empathy for this person and to value that person's experience (Batson, Chang, Orr, & Rowland, 2002).
Batson, C. D. Chang, J., Orr, R. & Rowland, J. (2002). Empathy, attitudes, and action: Can feeling for a member of a stigmatized group motivate one to help the group? Personality and Social Psychology Bulletin, 28, 1656-1666. http://dx.doi.org/10.1177/014616702237647
Hogg, M. A., & Abrams, D. (1990). Social motivation, self-esteem, and social identity. In D. Abrams & M. A. Hogg (Eds.), Social identity theory: Constructive and critical advances (pp. 28-47). New York, NY: Harvester Wheatsheaf.
Mio, J. S., Barker, L. A., & Tumambing, J. S. (2012). Multicultural psychology: Understanding our diverse communities (3rd ed.). New York, NY: Oxford University Press.
Tajfel, H. & Turner, J. C. (1986). The social identity theory of intergroup behavior. In W. G. Austin & S. Worchel (Eds.), Psychology of intergroup relations (2nd ed., pp. 7-27). Chicago, IL: Nelson-Hall.
Williams, K. D. (2001). Ostracism: The power of silence. New York, NY: Guilford Press.