The Science of Music and Memory
The Forgetting Curve and the Practice of Remembering
Failing to recall some of yesterday's learning is ordinary. Forgetting varies with the learner, material, and conditions, so review works better as an adjustable routine than a fixed formula.
Forgetting is a feature, not a failure
In the late 19th century, Hermann Ebbinghaus memorized nonsense syllables and plotted changes in retention. Later work has also found a rapid-then-slower decline, but the curve changes with the material, method, and learner. It is not one universal equation.
Relearning can improve later retention, but each review does not flatten the curve by a guaranteed amount. A practical approach is to expect some forgetting, test what you can recall, and adjust the next review from that result.
Recalling beats rereading
There is also science about how to review. Trying to recall something with the book closed (retrieval practice) beats reading it again — an effect so robust that researchers call it the testing effect, one of the most replicated findings in learning science.
The slight struggle of trying to remember is itself what strengthens the memory. Rereading, by contrast, produces a comfortable feeling of familiarity that is easily mistaken for knowledge. That moment in an exam when the page 'looked familiar' but the answer wouldn't come? That's the gap between recognizing and recalling.
Making it happen in real life
The theory is simple; managing review schedules in a planner is not. The realistic answer is to embed review into routines that already repeat: tie learning to your commute, make the three minutes before sleep a recall session, and meet the same material in more than one format — reading, listening, testing.
Audio makes it convenient to revisit familiar material, but exposure alone does not automatically flatten a forgetting curve. After a short listen, recall the main points without looking. Re-exposure and active retrieval serve different roles and work well together.