Memory

The idea of that chapter is simple: One major characteristic of long term memory is its stability. In other words, information is anchored deeply in the brain.

However, I am sure you all have the same experience that without regular practice, information that we learn gradually fade out from our memory. The very theory proposed by the Polish researcher Piotr Wozniak and summarized by Krogerus and Tschappeler is this: The amount of time it takes for us to forget what we learn is predictable. To go one step forward, if we want to make a piece of information our long term memory, we should be reminded while we are in the process of forgetting.

More importantly, it is not necessary to be reminded very many times to secure a long term memory. Based on the work of Wozniak, refreshing of the memory should ideally be done one, ten, thirty, and sixty days after encountering a new piece of information,

This is called spaced repetition.

PS. For medical students (and almost everyone else), the obvious difficulty is how to set up a reliable system of regular revision and refreshing. That's another story.