“I get sick of people taking my psych intro class and coming back next year and not remembering anything,” Melody Wiseheart, a psychologist at York University in Toronto, told me. “It’s a waste of time and money; people pay a lot for college. As a teacher, too, you want to teach so that people learn and remember: That’s your job. You certainly want to know when it’s best to review key concepts—what’s the best time, given the spacing effect, to revisit material? What is the optimal schedule for students preparing for a test?”
