We think of memories as something that we pick up along the way; little scars on our brains that show the journey that we have traveled. When we want to recall a memory we imagine that we go into a filing system, locate the memory and replay it from the original space on the hard drive. However this is not how memory works, not least because this is not how we perceive the world.
Memory, memory storage and memory retrieval is much more like cake making.
Our brains are like walk-in pantries with all of the different aspects of our experience (conscious and subconscious) stored in separate places on the shelves lining the walls. What we see is stored in a jar on a different shelf from what we hear, think, feel etc. The smell of an experience is placed in a jar right in the front, whereas sight is stored right at the back.
The cook in the middle puts the ingredients into the various jars as they occur. Then when that memory needs to be recalled they go to the different jars and build the memory from the different elements; they reconstruct the cake. However, it isn’t the original cake, it’s a new cake formed from the ingredients. Which is why the new cake can be a bit wrong and is partly why two people observing the same thing can recall it completely differently.
To learn something accurately we need to repeatedly make the cake, checking the recipe, using as many ingredients as possible, in order to make the connections between the correct jars really strong, bringing them to the front of the shelves.
Then eat the cake. I’m not sure how this fits into the analogy, but eating cake is a great thing to do. And using your brain requires calories.