Assess masking behavior during the COVID-19 pandemic using Alice and Bob’s dating dilemma
Assess masking behavior during the COVID-19 pandemic using Alice and Bob’s dating dilemma

Assess masking behavior during the COVID-19 pandemic using Alice and Bob’s dating dilemma

In a recent study posted to medRxiv* preprint server showed researchers that Alice and Bob’s dating dilemma (ABD) was a strong abstraction to evaluate masking behavior during the 2019 coronavirus disease pandemic (COVID-19).

Examination: To mask, or not to mask, Alice and Bob’s dating dilemma. Image Credit: Letters-Shmetters / Shutterstock


Face masking during the current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic appears to be a deceptively simple decision dilemma given its multifaceted nature. Masking raises questions in human behavior, biology, physics, and epidemiology.

While research has shown that masks work in general, human behavior complicates the situation drastically.

About the study

The aim of the current study was to propose a game theory framework for the study of complex decision-making issues in the development of public health policy, specifically in the context of the COVID-19 pandemic. Investigators used evolutionary game theory to unravel the potential misunderstanding of masking dilemmas during the COVID-19 pandemic, particularly the consequences of dishonesty and irrationality.

The current game theory study does not include any research experiments other than simulations. The researchers formulated and analyzed the masking problem as an extended Sir Philip Sydney (SPS) evolutionary game with a hypothetical pair, Alice and Bob, influenced by the cryptographic figures in computer science and the handicap principle of evolutionary biology.

The authors assumed that Alice and Bob were professional hackers before the SARS-CoV-2 pandemic. In addition, the authors proposed ABD as a non-symmetrical four-to-four strategic-shape game. Additionally, in the current ABD model, the kinship parameter (k) depicts the closeness of the love relationship between Alice and Bob and quantifies their mutual interests in masking-or-not-making decision-making.

Finds and discussions

The study results indicated 16 possible alternatives or strategy combinations, considering the ABD problem as an asymmetric four-to-four strategic-form SPS game. Based on the 16 possible strategic combinations, the authors described six types of equilibria and their benefits, including fitness. These equilibria could be differentiated as pooling, polymorphic hybrid, and separation (signaling), and they may have different behavioral and payout aspects.

In addition, their stability may differ significantly, resulting in theoretical and practical implications. These consequences have been thoroughly and adequately documented in the existing literature. On the other hand, the authors stated that their practical implications were far more complicated.

The six kinds of equilibria theoretically derived from the game model adequately described the various norms of masking that emerged around the world as the COVID-19 pandemic progressed, despite the exhibited complications of the ABD game model. These norms cover a wide range of behaviors among masked believers, converts, skeptics, voluntary masking, universal masking, coexisting or divided world of skeptics and believers.

In addition, the formation of these norms has undoubtedly been influenced by several social, scientific and other complex factors and, most importantly, the severity of the COVID-19 pandemic. Furthermore, the authors found that these norms were currently at different levels of stability and were predicted to continue to change as the SARS-CoV-2 pandemic progressed.


According to the authors, this was the first study that used game theory to investigate masking techniques.

The study results revealed 16 strategic interactions from the proposed ABD asymmetric four-to-four strategic form game. Of the 16 strategic interactions, six can achieve equilibrium with distinct features such as pooling, separation, and polymorphic hybrid, being Nash, neutrally stable, or evolutionarily stable. The six types of equilibrium tend to reflect the distinct behavior of converts, skeptics, masked believers, universal masking, voluntary masking, coexisting, or separate worlds of skeptics and believers.

The study showed that the seemingly simple ABD game was sufficiently general to analyze population masking policies through replicator dynamics. It was also useful for exploring other complex SARS-CoV-2 pandemic decision-making issues such as aggressive tracking versus privacy protection, herd immunity versus quarantines, and lockdown versus reopening.

In addition, the authors stated that the current strategy was specifically suited to address issues of dishonesty and irrationality in simulating masking strategies, since 1) evolutionary game theory was not plagued by the rationality assumption similar to classical game theory and 2) the handicap principle and its evolutionary game model were designed to adequately deal with the probable deception in communication.

*Important message

medRxiv publishes preliminary scientific reports that are not peer-reviewed and therefore should not be considered as crucial, guide clinical practice / health-related behavior or be treated as established information.

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