App-based Epidemic Game to Model Belief-Behavior Mapping and Cost Incentives in Voluntary Quarantine: A Randomized Controlled Trial

BackgroundUnderstanding the drivers of protective behavior during infectious disease outbreaks is critical for public health policy. App-based experimental epidemic games (epigames) offer a novel method to study these behaviors empirically, but their external validity--how well in-game choices reflect real-life beliefs--still needs to be rigorously tested. MethodsWe conducted a two-week randomized controlled trial (N=567) using the Epigames smartphone app at the American University of Iraq - Baghdad (AUIB) campus in the Middle East. This app used Bluetooth communication to sample the contact network between participants in sub-minute resolution and simulated the spread of a hypothetical respiratory virus through this network. Participants were randomized into two groups with differing opportunity costs (in-game points) for adopting voluntary quarantine within the game that would protect them from the simulated infection: Group 1 (Low Barrier) faced a small point difference between quarantine and non-quarantine choices, while Group 2 (High Barrier) faced a much larger difference. The optimal point difference between groups was determined by a Willing to Accept (WTA) pilot survey prior to the epigame. We measured real-life health beliefs and in-game beliefs through surveys at the beginning of the epigame, including questions on susceptibility, severity, self-efficacy, and benefits, to calculate the correlation between the two and to construct a Health Belief Model (HBM) parameterized by game data. We also measured self-assessment of game realism and behavior via an exit survey. ResultsReal-life and in-game beliefs showed moderate positive (Spearmans coefficient {rho} from 0.13 to 0.36) and statistically significant (p-value < 0.05) correlation across all survey measures, suggesting indicator (behavior) parallelism between real-life and the epigame. The exit survey also yielded positive self-assessment of context and behavior realism during the epigame. While simple aggregate analysis showed no significant difference in quarantine rates between Groups 1 and 2, a Poisson regression model revealed a significant crossover interaction. High economic barriers significantly reduced quarantine adoption among participants with low in-game motivation (interaction coef. = -2.22, p < 0.01). Perceived benefits appeared to moderate this effect at a near significance level (coef. = +0.33, p < 0.08). Demographic factors such as gender appeared to be significantly correlated with quarantine choice (p < 0.01). Analysis of the contact network measured with the app through Bluetooth showed assortative properties of several belief variables. ConclusionThis is the first systematic pre-registered study on the external validity of app-based epigames and the impact of economic cost and individual beliefs on protective behaviors. We found that economic barriers act as a "gatekeeper" for quarantine during the game, suppressing action among the skeptical while allowing highly motivated individuals to act. The significant correlation between real-life, in-game beliefs, and network structure suggests that epigames are a valid experimental tool for network-aware behavioral epidemiology. This warrants further studies for replication, examining variance across settings, and addressing limitations (e.g., crosstalk between groups) and technical issues (e.g., Bluetooth connectivity) in the study design. Study pre-registration: https://osf.io/qev6n/