Background: There's this effect when you have some idea, i.e. that eating other people is (probably) cool, you join the group of like minded people, you talk about how tasty people are, everyone agrees with you, which reinforces the idea, and you all share literature and articles and youtube videos and whatnot on how cool it is, and the longer you all participate in the people eating community the more sure you are that it's cool because of all the friend confirmation and the info you see and share and so on reinforces the belief stronger and stronger, and you don't meet people with opposite ideas that often, don't read criticism on eating people that often, etc. And the people eating idea is no longer just probably cool to you, you become sure about it with all your heart and defend it fanatically.

I am pretty sure I've read about this in some Peter L. Berger's book, however I cannot find it.

What is the name of this effect? (i.e., whereby being part of a group strengthens your belief in the beliefs held by the group)


3 Answers 3


It seems like you are talking about a number of social processes related to internalising group norms. With regards to the influence that groups can have on beliefs, check out:

Groups internalize norms by accepting them as reasonable and proper standards for behaviour within the group. Once firmly established, a norm becomes a social fact, and thus, a part of the group's operational structure, and is difficult to change. With that being said, newcomers to a group can change a group's norms. However, it is much more likely that the new individual entering the group will adopt the group's norms, values, and perspectives, rather than the other way around.

You also describe a process by which individuals are attracted to groups initially. You might want to look into the concept of homophily. This is the "tendency of individuals to associate and bond with similar others." There is substantial sociological and psychological research on this topic. Shared beliefs cause relationship formation, but presumably also, relationships cause increases in the likelihood of shared beliefs.


There is also the related phenomenon of 'Group Polarisation' (see Myers and Lamm, 1976; Isenberg, 1986), where groups are found to make more extreme decisions and hold more extreme opinions than its constituent members. Not sure if that's specifically related to what you're looking for but I think it's important to keep in mind.


  • Isenberg, D.J. (1986). Group polarization: A critical review and meta-analysis.. Journal of Personality and Social Psychology, 50, 1141. PDF
  • Myers, D.G. & Lamm, H. (1976). The group polarization phenomenon.. Psychological Bulletin, 83, 602.

All the points Jeromy made in his first answer can be integrated when you view this from the perspective of Self Categorization Theory (Turner et al., 1987) or newer develoments in social psychology which link Social Identity Theory and Self Categorization Theory (Haslam et al., 2009). To be sure, what I am about to say refers to the situation that an individual does already identify with a certain group.

The basic idea is that within a social context, certain cues can make the membership with a certain group salient, which leads to self categorization as a group member (instead of categorization as an individual). This in turn will lead to a heightened awareness of and conformity to norms, values or behaviours that belong to the group. Certain behaviours might even be essential to the definition of that group, like in your example. To provide a (hopefully) more realistic example, certain health-related behaviours like eating certain kinds of foods can be a defining feature of group identity. Oyserman et al. (2007) showed that

Racial-ethnic minority participants view health promotion behaviors as White middle class and unhealthy behaviors as in-group defining (Studies 1 and 2). Priming race-ethnicity (and low socioeconomic status) increases health fatalism and reduces access to health knowledge (Studies 3 and 4). Perceived efficacy of health-promoting activities is undermined when racial-ethnic minority participants who identify unhealthy behavior as in-group defining are asked to consider their similarities to (middle-class) Whites (Studies 5-7).

So, certain norms, values or behaviours might be relevant to the definition of a group and thereby important for the social identity of a person. As an answer to your question, a term that might fit is Self Categorization.


Haslam, S. Alexander, Jolanda Jetten, Tom Postmes, und Catherine Haslam (2009). Social identity, health and well-being: An emerging agenda for applied psychology. Applied Psychology 58, 1–23.
Oyserman, D., Fryberg, S. A., & Yoder, N. (2007). Identity-based motivation and health. Journal of Personality and Social Psychology, 93(6), 1011.
Turner, J. C., Hogg, M. A., Oakes, P. J., Reicher, S. D., & Wetherell, M. S. (1987). Rediscovering the social group: A self-categorization theory. Basil Blackwell.


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