Humans can reason across multiple domains (e.g., syllogistic, conditional, relational reasoning). Previous research has often investigated these domains in isolation, hence often identifying domain-specific strategies. A fundamental question in cognitive science is, however, if we apply rather a more general reasoning process or more domain-specific mechanisms. To approach this question and allow for analyses and modeling across domains, we first present a general data set that is well-grounded in the state-of-art of reasoning research and covers not only syllogistic, conditional and spatial reasoning, but also includes a test battery (e.g., memory). Second, we investigate relationships between the domains and present a preliminary step towards cross-domain modeling by predicting an individuals' syllogistic conclusion based on behavior observed in the other domains. Our results show that domains are heavily interrelated with subtle differences between domains, highlighting the need for explanations that integrate subtle domain-specific strategies in a general theory of human reasoning.