Psychological theories of emotion and cognition agree that emotional experiences play an important role in decision making and risk evaluation. For emotions to influence decision-making, individuals need to perceive these emotional signals (i.e. interoception), and appraise them appropriately (e.g. attribute as an internal state). These processing stages have been found to be abnormal in some forms of mental illness. In gambling behaviour, it is assumed that abnormal levels of arousal are a source of reinforcement and can lead to problematic gambling participation. Yet, the underlying mechanisms remain unclear, and emotional signals alone (e.g. heart rate changes) do not reliably differentiate people with and without gambling problems. The current project will clarify the role of arousal in disordered gambling to close this knowledge gap by using a novel approach to separate the contributions of arousal perception, and the influence of risk and ambiguity on arousal and the appraisal of arousal. Work package (WP) 1 will record psychophysiological measures of arousal in people who gamble, and assess their relationships with the subjective perception of arousal. WP 2 will examine the influence of risk and ambiguity on the ability of arousal to predict decision making. WP 3, will investigate whether unrelated (‘incidental’) arousal is attributed to the gambling episode and influences decision making in gambling behaviour. Combining computational modeling and psychophysiological measurements is a new experimental approach which will give additional insights in identifying which of these emotional dimensions are perturbed in gambling. The proposed research will have implications for gambling policy, and targeting emotional components in prevention and treatment of gambling addiction.