What determines the effect of caffeine upon memory?

In this paper, we sought to understand what determines whether caffeine affects memory so that we could learn how to use that to our advantage as students. Previous research has found the effect of caffeine upon memory is influenced by variables such as sleep, anxiety, and aerobic exercise. In our correlational study, we tested the strength of these relationships by examining naturalistic daily changes in their variables longitudinally over a period of two weeks. We measured caffeine intake by the total mg of caffeine consumed, sleep duration by the total hours spent sleeping, sleep quality by a subjective scale, anxiety by the State-Trait Anxiety Inventory, exercise duration by the total number of minutes of aerobic exercise, exercise intensity by a subjective scale, and memory performance by the n-back task at the end of each day. Data pooled and standardized across participants in our study showed that memory performance was not significantly correlated with caffeine intake but was significantly positively correlated with sleep duration and significantly negatively correlated with both anxiety and exercise intensity. The relationship between caffeine intake and memory performance was not significantly moderated by any of the study variables except for sleep duration, with memory performance showing a positive relationship with caffeine intake when sleep duration was at below average amounts.