Why We Forget What We Read
Last month I finished a book I had been looking forward to for weeks. Two weeks later, a friend asked me what it was about, and I could recall almost nothing. The plot was there, somewhere, but the details felt ephemeral, like a dream that fades a few minutes after you wake up. This is not a personal failing. In the 1880s, the German psychologist Hermann Ebbinghaus ran a meticulous series of experiments on his own memory. He memorized lists of nonsense syllables, waited, and then measured how much work it took to learn each list again. A day later, relearning a list saved him only about a third of the original work; a month later, about a fifth. Plotted over time, the savings drop steeply at first and then flatten out, a shape now known as the forgetting curve (Ebbinghaus, 1885, ch. 7). In 2015, Jaap Murre and Joeri Dros repeated the experiment and got results very close to his (Murre & Dros, 2015). ...