When we listen to something that resonates, a conflict starts in our minds. On the one hand, our brain elaborates on the material, connecting it to more mature pictures. On the other hand, there's an urge to forget what we heard and watched.

There's a sweet spot when forgetting an idea balances elaboration.

That's when we should process notes.

Forgetting vs. Learning

Hermann Ebbinghaus in 1880 was the first to experiment with memory retention. His observations suggested that humans tend to halve their memory of newly learned knowledge in a matter of days or weeks. He called this model the Forgetting Curve.

Later scientists showed that review of the learned material reinforces learning. In particular, Bryan and Harter in 1903 describe a rapid rise in proficiency at the beginning of a training program followed by a period of slower learning. We now call their model the Learning Curve.

Many researchers built the experimental edifice from those pioneer works. What is surprising is that the rate and shape of forgetting and improvement are fairly common across different tasks.

The best interval to review notes

We are learning machines as much as we are forgetting machines. But those opposing forces are not equally strong. Forgetting is the inevitable destiny of thoughts and ideas.

The sweet spot for note review and processing is soon enough to avoid losing all the information, but late enough so that our brain has time to digested thoughts. For ordinary ideas, something between 2 and 3 days. For ideas that strongly resonated, a couple hours might be enough as emotional attachment tends to speed learning.