What is social identity theory?
How sorting people into categories, the groups they join and the several groups they hold at once become part of the self.
Answer to the question
What is social identity theory?
Social identity theory is the account of how belonging to groups becomes part of who a person is. People sort themselves and others into categories, identify with some of them, and compare their own group with others. Henri Tajfel and A. L. Wilkes showed the first step in 1963: classes make members look alike and classes look apart.
Key takeaways
- Tajfel and Wilkes (1963) found that when classes followed a physical scale, items in different classes were judged further apart than in an unclassified series.
- Social identity theory holds that people sort themselves and others into categories, take part of their self-description from them, and compare their own group with others.
- In three field studies, university students wore school-identifying clothing more after a football win than a loss and used the word we more often for a win (Cialdini and colleagues, 1976).
- Social identity complexity is the perceived overlap among a person's in-groups; less overlap means greater complexity (Miller, Brewer and Arbuckle, 2009).
- Brewer (1991) proposed optimal distinctiveness: identity is strongest for categories that give belonging and distinctiveness together.
Stimuli sorted into classes look more different from one another than the same stimuli left unsorted. Henri Tajfel and A. L. Wilkes reported this in an early paper on classification and judgement, using items that varied along a physical scale. When the classes followed the scale, items in different classes were judged to be further apart than items in an unclassified series. When the classes had nothing to do with the scale, the effect did not appear. The authors connected the result to stereotyping, and it became the first piece of social identity theory, a larger account of how people see groups.
Social identity theory holds that people sort themselves and others into social categories, take part of their sense of who they are from the categories they belong to, and judge their own group against others. Tajfel went on to develop the account with John Turner, and later work extended it into self-categorization theory.
Social identity theory starts with sorting
Tajfel and Wilkes tied their finding to stereotyping, and the link is direct. They reported that past experience with classification increased the apparent differences between classes and the apparent similarity within a class. A category does two things at once: it makes the members of a class look alike, and it makes one class look apart from another.
People are sorted in the same way. A shirt, an accent or a badge tells an observer which category someone belongs to, and the sorting happens quickly. Michael Morris builds much of Tribal on this speed, describing how cues of belonging steer who people trust, copy and help. He argues that the pull is mostly warmth towards one's own group and not hostility towards outsiders.
What happens once people favour their own category, even one formed on almost no basis, is the subject of What is in-group bias. Sorting comes first, and social identity theory treats favouring as a later step. A plain label is enough to draw a boundary, and a boundary is enough to start the steps that follow, which is why a team jersey can matter to a stranger who has never met the wearer.
The category joins the self
The second idea in social identity theory is that a category stops being a label for other people and becomes part of how a person describes themselves. Researchers usually break that into three linked parts, which the table sets out. The shift matters because it changes what a group's fortunes mean to the person: a win or a setback for the group is then felt as a small win or setback for the self.
| Part | The question it answers | What it looks like |
|---|---|---|
| Categorisation | Which group is this, and am I in it? | Seeing members as alike and other groups as apart |
| Identification | How much is this group part of me? | Wearing its colours, saying we |
| Comparison | How does my group stand against others? | Caring about its success and image |
Read together, the three parts form a chain and not a menu. A person cannot identify with a group they have not classified, and the comparison matters only once the group is part of the self, which is why the same match can leave one spectator indifferent and another elated. The chain also explains why the theory is used to talk about teams, workplaces and neighbourhoods alike: the steps are the same, and only the groups differ.
Identification has a famous field test. Robert Cialdini and colleagues ran three field studies of university students and their football teams and found that students wore school-identifying clothing more after a win than after a loss, and used the word we more often when describing a win. The effect appeared even though the students had no part in the result. The authors proposed that people claim links to success to improve their public image, and in two studies people were keenest to claim a connection when their image was under threat. The full account of that pronoun is in Why We Say We Won When Our Team Wins.
The same study shows comparison at work. A group that is doing well is worth being tied to, so the tie is announced. In terms of social identity theory, part of the self-description rides on the group's standing, which is why members care about results they had no hand in.
Several groups at once
Nobody holds one social identity, so social identity theory has to allow for many categories at once. A person can be a parent, a colleague, a supporter, a member of a faith or a neighbour, and those groups may overlap a great deal or hardly at all. Sonia Roccas and Marilynn Brewer called this social identity complexity, the way a person perceives the overlap among their in-groups. The less overlap a person perceives, the greater the complexity. Someone whose colleagues, neighbours and fellow supporters are all the same people has low complexity, and someone whose circles hardly meet has high complexity.
Kevin Miller, Marilynn Brewer and Nathan Arbuckle tested what goes with it in three studies. Earlier research had linked complexity to tolerance and positive feelings towards other groups. In their first study the trait predicted both explicit and implicit attitudes towards racial groups, independent of political ideology and cognitive style. In the second, a manipulation showed that need for cognition causally influenced perceived overlap and later complexity scores. The third, a large field study with a diverse sample, examined how living in an ethnically complex environment relates to the trait.
The practical reading is that social identity theory describes a self made of several memberships and not a single badge. Which one comes to the front depends on the setting, and a workplace, a stadium and a family dinner each bring a different one forward, so the same person can speak as a parent at one moment and as a supporter at the next. Why Do We Need to Belong sets out the motive that makes each of those memberships matter.
Belonging pulls against distinctiveness
Why do some groups hold people more tightly than others, and why does a person who belongs still want to stand out? Marilynn Brewer's answer, published in 1991, is optimal distinctiveness. People have two opposing needs, to be assimilated into something larger and to be set apart from others, and social identity reconciles them. People avoid self-construals that are too personal or too inclusive, and loyalty should be strongest for categories that offer belonging and distinctiveness together.
A group that is too large dilutes the sense of being different, and a group that is too small cannot supply much belonging. On this account a mid-sized club can feel closer than a nation or a very small circle, and social identity theory gains a way to explain why some memberships are held more tightly than others.
Brewer's first experiment supported the prediction that depersonalisation and group size interact in setting the strength of identification.
Common questions
What is social identity theory?
It is the account of how belonging to groups becomes part of who a person is. People sort themselves and others into categories, identify with some of them, and compare their own group with others.
Who developed social identity theory?
Henri Tajfel developed it with John Turner, building on his early work on classification and judgement. Turner and colleagues later extended it into self-categorization theory.
How is social identity theory different from in-group bias?
In-group bias is a finding, the favouring of one's own group. Social identity theory is the wider account of why group membership matters to the self, of which favouring is one consequence.
Can a person have more than one social identity?
Yes. Research on social identity complexity looks at how much a person perceives their groups to overlap, and links the trait to attitudes towards other groups.
Sources
Morris, M. Tribal. Seed book; vault hub Books/Tribal.
Tajfel, H., & Wilkes, A. L. (1963). Classification and quantitative judgement. British Journal of Psychology, 54(2), 101-114. doi:10.1111/j.2044-8295.1963.tb00865.x https://doi.org/10.1111/j.2044-8295.1963.tb00865.x
Cialdini, R. B., Borden, R. J., Thorne, A., Walker, M. R., Freeman, S., & Sloan, L. R. (1976). Basking in reflected glory: Three (football) field studies. Journal of Personality and Social Psychology, 34(3), 366-375. doi:10.1037/0022-3514.34.3.366 https://doi.org/10.1037/0022-3514.34.3.366
Brewer, M. B. (1991). The social self: On being the same and different at the same time. Personality and Social Psychology Bulletin, 17(5), 475-482. doi:10.1177/0146167291175001 https://doi.org/10.1177/0146167291175001
Miller, K. P., Brewer, M. B., & Arbuckle, N. L. (2009). Social identity complexity: Its correlates and antecedents. Group Processes & Intergroup Relations, 12(1), 79-94. doi:10.1177/1368430208098778 https://doi.org/10.1177/1368430208098778
Tajfel, H., & Turner, J. C. (1979). An integrative theory of intergroup conflict. In W. G. Austin & S. Worchel (Eds.), The social psychology of intergroup relations. Brooks/Cole.