How identity fusion predicts extreme pro-group orientations: A meta-analysis

ABSTRACT

Researchers have productively tested identity fusion theory, aiming to explain extreme pro-group orientations. However, the strength of effects, types of measurements, and study contexts have varied substantially. This first meta-analysis (90 studies from 55 reports, 106 effects, N = 36,880) supported four main conclusions based on the available literature: (1) identity fusion has a strong and positive but very heterogeneous relationship with extreme pro-group orientations; (2) its effect is significantly stronger than that of social identification; however, some evidence suggests that this difference is primarily observed in published rather than unpublished studies; (3) the verbal identity fusion scale has the best explanatory power; (4) identity fusion is most strongly associated with extreme collective action, followed by a willingness to sacrifice oneself, fight or die for the group, and outgroup hostility. We discuss the findings’ implication for identity fusion theory. Based on the literature’s limitations, we highlight avenues for future research.

KEYWORDS:

• Extremism
• identity fusion
• social identity
• violence
• meta-analysis

Notes on contributor

A.H.V., J.R.K., L.K., and K.B. designed the study. A.H.V. and L.K. conducted the literature search and coded the studies. K.B., J.R.K., L.K., and A.H.V. analysed the data. A.H.V., J.K., L.K. and K.B. drafted and revised the first version of the manuscript. A.G. and A.V. provided critical feedback and revisions. J.R.K., K.B., and A.G. revised the manuscript. A.V., A.H.V. and L.K. provided critical feedback.

Acknowledgments

We thank Dinh Hung Vu for assisting in the coding of the studies. J.R.K. was supported by an EEA Norway Grants, 2020-2024 for the project APVIOLEXT (PL-Basic Research-0011). A.V. was supported by grant PID2021-126085OB-I00, funded by the Ministry of Science, Innovation, and Universities of Spain. A.G. was supported by ERC Advanced Grant, Agreement nr. 101018172, A Multi-Theory Approach for Preventing and Reducing Radicalization leading to violence-MULTIPREV, and grant PID2021-124617OB-I00 from the Spanish Ministry of Science and Innovation.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The full dataset, R code, and supplementary online materials (SOM) are available via https://osf.io/za4rj/?view_only=3980c9e81fac401e83ce6837f41e4f67.

Notes

¹ In this paper, we use the term “heterogeneity” strictly in the statistical sense, as referring to the variability in size of the association between fusion and outcomes within and between studies.

² Please note that 95% CIs or p values cannot be calculated for less than 3 effects.

Additional information

Funding

The work was supported by the EEA Grants/Norway Grants [PL-Basic Research-0011]; European Research Council [101018172]; Ministerio de Ciencia e Innovación [PID2021-124617OB-I00]; Ministerio de Ciencia, Innovación y Universidades [PID2021-126085OB-I00]