It’s important to remember the things you learned, particularly when studying for an equivalency exam like the College Level Examination Program CLEP® Test.

Wired Magazine just came out with an article that describes memory retention in terms of how one forgets, specifically the pattern and rate at which one forgets material they just learned. It’s a study in cognitive psychology that has been known for some time but is just now picking up momentum.

Rendering of Projected Forgetting Over Time
"SuperMemo is a program that keeps track of discrete bits of information you've learned and want to retain. For example, say you're studying Spanish. Your chance of recalling a given word when you need it declines over time according to a predictable pattern. SuperMemo tracks this so-called forgetting curve and reminds you to rehearse your knowledge when your chance of recalling it has dropped to, say, 90 percent. When you first learn a new vocabulary word, your chance of recalling it will drop quickly. But after SuperMemo reminds you of the word, the rate of forgetting levels out. The program tracks this new decline and waits longer to quiz you the next time."
Wired

It works like this; one studies Spanish or French on a Saturday. It is likely that he or she will remember 99% of their study session an hour later. However on Monday, just two days later, his or her memory retention has dropped 10%. A week later, retention has lost up to 50%. This continues on exponentially. Cognitive psychology has found through research that we can significantly reduce this forgetfulness by revisiting our studies at specific intervals in time, the time at which we are most likely to forget. This is called the spacing effect. Recalling learned knowledge at known intervals, i.e. when recollection has dropped to 90% in 2 days, brings your retention back up to normal levels. At this point, it takes 8 days to fall to 90% at which point you repeat the cycle. The curve for forgetting (see below,) begins to fade.

There are now a couple of software applications available to help remind us when to study: SuperMemo and Mind Burn, perfect for studying CLEP® practice questions!