Caffeine and cognition: a cognitive architecture-based review

Caffeine is a chemical that is commonly ingested by people daily to modify their behavior. Its physiological and psychological effects have been studied extensively for theoretical and applied reasons. We briefly review the current information on caffeine's physiological effects. We then review caffeine's effect on cognition and summarize these effects as changes in cognitive architectures (a fixed set of mechanisms to explain cognition), which provide a unified way to represent the changes. Modeling the effects of caffeine on an individual's physiology, as well as their cognitive function, is a logical addition to cognitive architectures because caffeine moderates cognitive performance. Cognitive architectures have recently been connected with physiological simulators, allowing physiological variables to interact with cognition. This combination provides a natural way to represent caffeine in current cognitive architectures and model how cognition and physiology interact, and use such models in system design. Our review notes how caffeine influences several aspects of users' capabilities that will influence system performance. It also notes gaps in the caffeine literature needed to improve models of users, including studies on the distribution of half-life, the need for the use of dosages vs. doses, and task-based effect studies.