Abstract:We developed a simulation game to study how well decision makers understand two fundamental aspects of complexity in cybersecurity: potential delays in building capabilities, and uncertainties in predicting cyber-incidents. Analyzing 1,479 simulation runs, we compared the performances of a group of experienced professionals to an inexperienced control group. Experienced subjects did not understand the mechanisms of delays any better than inexperienced subjects. Both groups also exhibited similar errors when dealing with the uncertainty of cyber-incidents. Our findings highlight the importance of training for decision-makers, and lay the groundwork for future research in uncovering mental biases about the complexities of cybersecurity.