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Why are there so many extreme opinions online?: An empirical, comparative analysis of Japan, Korea and the USA

Shinichi Yamaguchi (Center for Global Communications, International University of Japan, Minami Uonuma Shi, Japan)

Online Information Review

ISSN: 1468-4527

Article publication date: 8 April 2022

Issue publication date: 18 January 2023




This study aims to verify the following hypothesis: People with extreme opinions post on social media more than those with moderate opinions.


A social media posting model was constructed to estimate the influence of extreme opinions on the number of social media posts in Japan, Korea and the USA. For a quantitative verification, data from 5,095 questionnaire surveys were regressed using a Tobit model.


Extreme opinions were found to increase the number of social media posts in all three countries and for both surveyed topics (constitutional amendment in Japan and increasing number of foreigners in Japan, Korea and the USA). Furthermore, the higher the interest in the topic, the greater the effect. The hypothesis was thus supported.

Research limitations/implications

The survey was conducted online, and the sample size in Korea and the USA was smaller than in Japan. The topics were limited to two, and only three countries were included.

Social implications

People should use social media knowing that there are numerous extreme views online. Companies that provide social media platforms should consider measures to ensure that users are not exclusively exposed to extreme opinions.


This research conducts a quantitative analysis on the effects of opinion extremity on social media posting behavior and the resulting bias in online opinion distribution, a topic on which there is scant prior research.

Peer review

The peer review history for this article is available at:



This work was supported by JSPS KAKENHI Grant Number JP18K12882 and JP21K12586. For that, the author would like to express his deepest gratitude. Further, the International University of Japan Center for Global Communications' research associates, Kotaro Iyanaga and Hirohide Sakaguchi, and research assistant, Hidetaka Oshima, lent the author their invaluable cooperation. Thank you very much.


Yamaguchi, S. (2023), "Why are there so many extreme opinions online?: An empirical, comparative analysis of Japan, Korea and the USA", Online Information Review, Vol. 47 No. 1, pp. 1-19.



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