The right side of his curve is encouraging: even years later, Ebbinghaus could expect old random gobbledygook to take him measurably less time to learn than new random gobbledygook. Once he learned something, a trace of it remained within him forever. Unfortunately, the left side is a disaster: our memories rush out of our ears like water through a net. The net stays damp, but if we’re trying to keep something substantial in it—like telephone numbers, the names of people we’ve just met, or new foreign words—we can expect to remember a paltry 30 percent the following day.
