Self-categorization theory is a theory in
social psychology
Social psychology is the scientific study of how thoughts, feelings, and behaviors are influenced by the real or imagined presence of other people or by social norms. Social psychologists typically explain human behavior as a result of the ...
that describes the circumstances under which a person will perceive collections of people (including themselves) as a group, as well as the consequences of perceiving people in group terms.
Although the theory is often introduced as an explanation of psychological group formation (which was one of its early goals), it is more accurately thought of as general analysis of the functioning of
categorization
Categorization is the ability and activity of recognizing shared features or similarities between the elements of the experience of the world (such as objects, events, or ideas), organizing and classifying experience by associating them to a ...
processes in
social perception and interaction that speaks to issues of individual identity as much as group phenomena.
It was developed by
John Turner and colleagues, and along with
social identity theory
Social identity is the portion of an individual's self-concept derived from perceived membership in a relevant social group.
As originally formulated by social psychologists Henri Tajfel and John Turner in the 1970s and the 1980s, social ...
it is a constituent part of the
social identity approach
The term social identity approach refers to research and theory pertaining to social identity theory and self-categorization theory—two intertwined, but distinct, social psychological theories. Haslam, A. S. (2001). Psychology in Organizations ...
. It was in part developed to address questions that arose in response to social identity theory about the mechanistic underpinnings of social identification.
[ Haslam, A. S. (2001). Psychology in Organizations. London, SAGE Publications.]
Self-categorization theory has been influential in the academic field of
social psychology
Social psychology is the scientific study of how thoughts, feelings, and behaviors are influenced by the real or imagined presence of other people or by social norms. Social psychologists typically explain human behavior as a result of the ...
and beyond.
[Postmes, T. & Branscombe, N. (2010). Sources of social identity. In T. Postmes & N. Branscombe (Eds). Rediscovering Social Identity: Core Sources. Psychology Press.] It was first applied to the topics of
social influence,
group cohesion,
group polarization
In social psychology, group polarization refers to the tendency for a group to make decisions that are more extreme than the initial inclination of its members. These more extreme decisions are towards greater risk if individuals' initial tendenci ...
, and
collective action
Collective action refers to action taken together by a group of people whose goal is to enhance their condition and achieve a common objective. It is a term that has formulations and theories in many areas of the social sciences including psych ...
.
[Turner, J. C., Hogg, M. A., Oakes, P. J., Reicher, S. D. & Wetherell, M. S. (1987). Rediscovering the social group: A self-categorization theory. Oxford: Blackwell] In subsequent years the theory, often as part of the social identity approach, has been applied to further topics such as
leadership
Leadership, both as a research area and as a practical skill, encompasses the ability of an individual, group or organization to "lead", influence or guide other individuals, teams, or entire organizations. The word "leadership" often gets v ...
,
personality
Personality is the characteristic sets of behaviors, cognitions, and emotional patterns that are formed from biological and environmental factors, and which change over time. While there is no generally agreed-upon definition of personality, mos ...
,
outgroup homogeneity, and
power.
One tenet of the theory is that the self should not be considered as a foundational aspect of
cognition
Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thoug ...
, but rather the self should be seen as a product of the cognitive system at work.
Aspects of the theory

Levels of abstraction
Drawing inspiration from cognitive psychology,
[Turner, J. C. & Reynolds, K. J. (2010). The story of social identity. In T. Postmes & N. Branscombe (Eds). Rediscovering Social Identity: Core Sources. Psychology Press.] self-categorization theory assumes that the self can be categorized at various levels of abstraction. In other words, humans may categorize the self as a singular "I"(personal identity), or as a more inclusive "we"(social identity). In the latter case the self is cognitively grouped as identical and interchangeable to other stimuli within that category.
It is argued that it is this variation in self categorization that underpins many intergroup phenomena,
including those described in social identity theory.
To demonstrate the notion of varying
levels of abstraction
{{Multiple issues, {{context, date=March 2018
{{unreferenced, date=August 2009
The principle of abstraction is a grouping principle, whereby a hierarchy is adhered to with higher levels of abstraction placed near the top with more specific concep ...
and inclusiveness, three types of self category are often given as examples.
The lowest level of abstraction is given as a personal self, where the perceiver self categorizes as "I". A higher level of abstraction corresponds to a social self, where the perceiver self categorizes as "we" in comparison to a salient outgroup (them). A highest level of abstraction is represented by ''we humans'', where the salient outgroup is animals or other non-humans. A common misconception is that these three example categories represent ''the'' self categories that humans use. Instead, the theory posits that there are innumerable self categories that a perceiver may use (see,
online category formation), and in particular that there are a myriad of different personal and social identities that a perceiver may invoke in his or her day-to-day life.
The misconception may also be attributable to the early writing of Turner where a singular social identity was contrasted against a singular personal identity.
This however predates the formal statement of self-categorization theory.
Accentuation
In self-categorization theory, categorizing people does not simply involve the redescription of characteristics and categories present in social stimuli. Rather, salient ''social categories'' form the basis of a social world that is enriched with meaning. This is achieved through a non-conscious process of accentuation, where ''differences between'' social categories are accentuated along with the ''similarities within'' social categories.
The resulting augmentation of social content allows the perceiver to interact with others with greater confidence and ease.
The accentuation component of self-categorization theory stems from prior research that demonstrated an
accentuation effect
Accentuation effect occurs when something (be it a person, place or thing) is placed into a category. The differences between the categories are then exaggerated, and differences within the categories themselves are minimised. Memory of anything th ...
for categorized non-social stimuli.
A prototypical example of non-social accentuation came from Tajfel and Wilkes, who found that when a categorization scheme corresponded to line length participants would view lines belonging to different categories as more different than if no categorization scheme was present.
Consistent with the idea that an efficient cognitive system would, where possible, use the same systems regardless of the social or non-social nature of the stimuli,
self-categorization theorists have demonstrated similar effects for social stimuli. For example, Haslam and Turner found that a perceiver would describe another person as more or less similar to themselves as a function of the likely categorization scheme.
Depersonalization and self-stereotyping
According to self-categorization theory, depersonalization describes a process of
self-stereotyping. This is where, under conditions of social category
salience and consequent accentuation, "people come to see themselves more as the interchangeable exemplars of a social category than as unique personalities defined by their differences from others".
Under these conditions a perceiver directly bases their behaviour and beliefs on the
norms, goals and needs of a salient ingroup.
[Brown, R. J. & Turner, J. C. (1981). Interpersonal and intergroup behaviour. In J. C. Turner & H. Giles (Eds.), Intergroup Behaviour (pp. 33-65). Oxford: Blackwell..] For example, if a person's salient self-category becomes 'army officer' then that person is more likely to act in terms of the norms associated with that category (e.g. to wear a uniform, follow orders, and distrust an enemy) and less likely to act in terms of other potential self-categories.
Here the person can be said to be accentuating the similarities between his or herself and other members of the 'army officers' category.
Turner and colleagues stress that depersonalization is not a loss of self, but rather a ''redefinition'' of the self in terms of group membership.
A depersonalized self, or a social identity, is every bit as valid and meaningful as a personalized self, or personal identity.
A loss of self is sometimes referred to using the alternative term
deindividuation
Deindividuation is a concept in social psychology that is generally thought of as the loss of self-awareness in groups, although this is a matter of contention (see below). For the social psychologist, the level of analysis is the individual in ...
. Further, although the term
depersonalization
Depersonalization can consist of a detachment within the self, regarding one's mind or body, or being a detached observer of oneself. Subjects feel they have changed and that the world has become vague, dreamlike, less real, lacking in significa ...
has been used in
clinical psychology
Clinical psychology is an integration of social science, theory, and clinical knowledge for the purpose of understanding, preventing, and relieving psychologically based distress or Mental disorder, dysfunction and to promote subjective mental ...
to describe a type of disordered experience, this is completely different from depersonalization in the sense intended by self-categorization theory authors.
The concept of depersonalization is critical to a range of group phenomena including social influence, social
stereotyping, in-group
cohesiveness
Group cohesiveness (also called group cohesion and social cohesion) arises when bonds link members of a social group to one another and to the group as a whole. Although cohesion is a multi-faceted process, it can be broken down into four main co ...
,
ethnocentrism
Ethnocentrism in social science and anthropology—as well as in colloquial English discourse—means to apply one's own culture or ethnicity as a frame of reference to judge other cultures, practices, behaviors, beliefs, and people, instead of ...
, intragroup
cooperation,
altruism
Altruism is the moral principle, principle and moral courage, moral practice of concern for the welfare and/or happiness of other human kind, human beings or animals, resulting in a quality of life both material and spirituality, spiritual. It ...
, emotional
empathy
Empathy is the capacity to understand or feel what another person is experiencing from within their frame of reference, that is, the capacity to place oneself in another's position. Definitions of empathy encompass a broad range of social, cog ...
, and the emergence of
social norms
Social norms are shared standards of acceptance, acceptable behavior by groups. Social norms can both be informal understandings that govern the behavior of members of a society, as well as be codified into wikt:rule, rules and laws. Social normat ...
.
Determinants of categorization
In self-categorization theory the formation and use of a social category in a certain context is predicted by an interaction between
perceiver readiness and category-stimulus fit. The latter being broken down into
comparative fit and
normative fit.
This predictive interaction was heavily influenced by
Bruner's accessibility and fit formula.
A social category that is currently in use is called a ''salient'' social category, and in the case of a self category is called a ''salient social identity''.
The latter should not be confused with ''level of identification'', which is a component of perceiver readiness.
Perceiver readiness
Perceiver readiness, which Turner first described as ''relative accessibility'',
"reflects a person's past experiences, present expectations, and current motives, values, goals and needs".
It is the relevant aspects of cognition that the perceiver brings to the environment. For example, a perceiver who categorizes frequently on the basis of nationality (e.g., "we
Americans
Americans are the citizens and nationals of the United States of America.; ; Although direct citizens and nationals make up the majority of Americans, many dual citizens, expatriates, and permanent residents could also legally claim Amer ...
") is, due to that past experience, more likely to formulate a similar self category under new conditions. Accordingly, ''social identification'', or the degree to which the group is valued and self-involving, may be thought of as an important factor that affects a person's readiness to use a particular social category.
Comparative fit
Comparative fit is determined by the meta-contrast principle—which states that people are more likely to believe that a collection of stimuli represents an entity to the degree that the differences between those stimuli are less than the differences between that collection of stimuli and other stimuli.
For predicting whether a group will categorize an individual as an ingroup or outgroup member, the meta-contrast principle may be defined as the ratio of the average similarity of the individual to outgroup members over the average similarity of the individual to ingroup members. The meta-contrast ratio is dependent on the context, or frame of reference, in which the categorization process is occurring.
[Turner, J. C. (1999). Current issues in research on social identity and self-categorization theories. In N. Ellemers, R. Spears, & B. Doosje (Eds), Social identity: Context, commitment, content (pp. 6-34) Oxford, UK. Blackwell.] That is, the ratio is a comparison based on whichever stimuli are cognitively present. For example, if the frame of reference is reduced such that potential outgroup members are no longer cognitively present, ingroup members regard the individual as less similar to the group and are less likely to categorize that individual as belonging to that group.
Normative fit
Normative fit is the extent that the perceived behaviour or attributes of an individual or collection of individuals conforms to the perceiver's knowledge-based expectations.
[Oakes, P. J., Haslam, S. A. & Turner, J. C. (1994). Stereotyping as social reality. Oxford, UK and Cambridge, MA: Blackwell.] Thus, normative fit is evaluated with reference to the ''perceiver readiness'' component of the categorisation process.
[Brown, P. M. & Turner, J. C. (2002). The role of theories in the formation of stereotype content. In C. McGarty, V. Y. Yzerbyt & R. Spears (Eds), Stereotypes as explanations: The formation of meaningful beliefs about social groups. Cambridge.] As an example of the role of normative fit in categorization, although a collection of individuals may be categorized as an entity on the basis of ''comparative fit'', they are only labelled using the specific social category of "science students" if perceived as hard working. That is, they fit the normative content of that category.
Online category formation
Self-categorization theorists posit "self-categorization is comparative, inherently variable, fluid and context dependent."
They reject the notion that self concepts are stored invariant structures that exist ready for application.
Where stability is observed in self perception this is not attributed to stored stable categories, but rather to stability in both the perceiver and the social context in which the perceiver is situated.
[McGarty, C. (1999). Categorization in social psychology. Sage Publications: London, Thousand Oaks, New Delhi.] This variability is systematic and occurs in response to the changing context in which the perceiver is situated. As an example, the category of
psychologists can be perceived quite differently if compared to
physicists
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe.
Physicists generally are interested in the root or ultimate caus ...
as opposed to
artists
An artist is a person engaged in an activity related to creating art, practicing the arts, or demonstrating an art. The common usage in both everyday speech and academic discourse refers to a practitioner in the visual arts only. However, the ...
(with variation perhaps on how
scientific
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
Science may be as old as the human species, and some of the earliest archeological evidence ...
psychologists are perceived to be).
In self-categorization theory contextual changes to the salient social category are sometimes referred to as shifting
prototypicality.
Although the theory accepts that prior categorization behaviour impacts present perception (i.e., as part of perceiver readiness), self-categorization theory has key advantages over descriptions of social categorization where categories are rigid and invariant cognitive structures that are stored in comparative isolation prior to application. One advantage is that this perspective removes the