At the risk of repeating myself... it depends on the properties of the marshmallow-test task. If it is such that my intuitions about it predict the actual task pretty well, then I should just start taping pasta. If it is such that my intuitions about it predict the task poorly, I might do better to study the system... although if there's a time limit, that might not be a good idea either, depending on the time limit and how quickly I study.