King's College London

Research portal

How epidemic psychology works on Twitter: evolution of responses to the COVID-19 pandemic in the U.S.

Research output: Contribution to journalArticlepeer-review

Luca Maria Aiello, Daniele Quercia, Ke Zhou, Marios Constantinides, Sanja Šćepanović, Sagar Joglekar

Original languageEnglish
Article number179
JournalHumanities and Social Sciences Communications
Issue number1
PublishedDec 2021

Bibliographical note

Funding Information: We thank Sarah Konrath, Rosta Farzan, and Licia Capra for their useful feedback on the manuscript. This research was partly supported by the EU Grant “GO GREEN ROUTES” no. 869764. Publisher Copyright: © 2021, The Author(s). Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

King's Authors


Disruptions resulting from an epidemic might often appear to amount to chaos but, in reality, can be understood in a systematic way through the lens of “epidemic psychology”. According to Philip Strong, the founder of the sociological study of epidemic infectious diseases, not only is an epidemic biological; there is also the potential for three psycho-social epidemics: of fear, moralization, and action. This work empirically tests Strong’s model at scale by studying the use of language of 122M tweets related to the COVID-19 pandemic posted in the U.S. during the whole year of 2020. On Twitter, we identified three distinct phases. Each of them is characterized by different regimes of the three psycho-social epidemics. In the refusal phase, users refused to accept reality despite the increasing number of deaths in other countries. In the anger phase (started after the announcement of the first death in the country), users’ fear translated into anger about the looming feeling that things were about to change. Finally, in the acceptance phase, which began after the authorities imposed physical-distancing measures, users settled into a “new normal” for their daily activities. Overall, refusal of accepting reality gradually died off as the year went on, while acceptance increasingly took hold. During 2020, as cases surged in waves, so did anger, re-emerging cyclically at each wave. Our real-time operationalization of Strong’s model is designed in a way that makes it possible to embed epidemic psychology into real-time models (e.g., epidemiological and mobility models).

View graph of relations

© 2020 King's College London | Strand | London WC2R 2LS | England | United Kingdom | Tel +44 (0)20 7836 5454