by Art Markman, Ph.D., Psychology Today
As you remember things, when they happened becomes important.
One of the most important functions of human memory is to give you information you need when you need it. If you’re programming a computer, you’d like to use any knowledge you have about programming to solve problems that come up. Your knowledge about cooking or driving is less relevant in that context.
As a result, one of the major factors that influence the structure of your memory is what psychologists call semantic similarity, or similarity in the meanings of things. If you see a duck, you will remember things that are related to ducks rather than to things very dissimilar to ducks.