Amygdala structure and the tendency to regard the social system as legitimate and desirable


Individual variation in preferences to maintain versus change the societal status quo can manifest in the political realm by choosing leaders and policies that reinforce or undermine existing inequalities1. We sought to understand which individuals are likely to defend or challenge inequality in society by exploring the neuroanatomical substrates of system justification tendencies. In two independent neuroimaging studies, we observed that larger bilateral amygdala volume was positively correlated with the tendency to believe that the existing social order was legitimate and desirable. These results held for members of advantaged and disadvantaged groups (men and women, respectively). Furthermore, individuals with larger amygdala volume were less likely to participate in subsequent protest movements. We ruled out alternative explanations in terms of attitudinal extremity and political orientation per se. Exploratory whole-brain analyses suggested that system justification effects may extend to structures that are adjacent to the amygdala, including parts of the insula and the orbitofrontal cortex. These findings suggest that the amygdala may provide a neural substrate for maintaining the societal status quo, and opens avenues for further investigation into the association between system justification and other neuroanatomical regions.

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Fig. 1: The relationship between grey matter volume in the bilateral amygdalae and system justification in study 1.
Fig. 2: Confirmatory replication in study 2 of a positive correlation between bilateral amygdala volume and system justification.
Fig. 3: Participants’ likelihood of participating in a protest during college.


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This work was supported by the Center for Brain Imaging at NYU, and a National Science Foundation Grant 1555131 (to J.J.V.B.). The funders had no role in study design, data collection and analyses, decision to publish, or preparation of the manuscript. We thank S. Wharton and A. Skwara for assistance with data collection, and E. Jackson for assistance with manuscript preparation. We also thank E. Knowles, P. Shrout, and C. Dawes, as well as members of the Social Perception and Evaluation Lab and the Social Justice Lab at NYU for helpful comments on this programme of research.

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H.H.N., J.T.J., and J.J.V.B. designed the research. H.H.N. and L.K. collected the data. H.H.N., L.K., and D.C.-M. analysed the data with input from J.T.J. and J.J.V.B. H.H.N. wrote the manuscript with input from all other authors.

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Correspondence to H. Hannah Nam.

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Nam, H.H., Jost, J.T., Kaggen, L. et al. Amygdala structure and the tendency to regard the social system as legitimate and desirable. Nat Hum Behav 2, 133–138 (2018).

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