In the last 50 years, there has been a boatload of research—that’s the technical term, by the way—confirming what most of us know intuitively: there is a definite connection between time and learning, with a higher quantity of the former generally leading to an increased amount of the latter. (For a brief review of the research, see the paper I put together a couple of years ago.) In fact, this direct association was first articulated, at least in a published paper, by the educational psychologist, John Carroll.