Ingroup Bias in a Social Learning Experiment

32 Pages Posted: 11 May 2021 Last revised: 18 Sep 2021

See all articles by Xue Xu

Xue Xu

School of Economics, Nankai University

Wenbo Zou

Nankai University

Date Written: May 11, 2021


Does social learning and subsequent private information processing differ depending on whether the observer shares the same group identity as the predecessor whose actions are observed? In this paper, we conduct a lab experiment to answer this question, in which subjects first observe a social signal and then receive a private signal. We find that subjects put greater weights on the social signal if they share with the predecessor the same group identity that is induced in the experimental environment. We also provide suggestive evidence that such ingroup bias cannot be explained by an ingroup-outgroup difference in beliefs of the predecessor’s rationality. Moreover, heterogeneous effects of group identity exist in weights given to the subsequent private signal: Compared to when the predecessor is an outgroup, those who have learned from an ingroup predecessor put a greater (smaller) weight on the private signal if it contradicts (confirms) the social signal. We conjecture that such group effects are consistent with that group identity is a framing device that can be easily replaced by alternative decision heuristics.

Keywords: ingroup bias, social learning, belief updating, laboratory experiment

Suggested Citation

Xu, Xue and Zou, Wenbo, Ingroup Bias in a Social Learning Experiment (May 11, 2021). Available at SSRN: or

Xue Xu

School of Economics, Nankai University ( email )

Weijin Road 94
Tianjin, 300071

Wenbo Zou (Contact Author)

Nankai University ( email )

94 Weijin Road
Tianjin, 300071

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