The Forgetting Curve In 1885, Hermann Ebbinghaus, a German psychologist, studied memory and published his findings in a book called Memory: A Contribution to Experimental Psychology .

We forget up to 90 percent of what we learn within a week. But it doesn’t have to be that way. You can beat the forgetting curve and make your learning stick—for good.

But then my colleague told me about the Ebbinghaus Forgetting Curve, a 100-year-old formula developed by German psychologist Hermann Ebbinghaus, who pioneered the experimental study of memory.