Our Ability to Forget

Today I'd like to present you with a simple theory.  This is the Ebbinghaus forgetting curve:

It theorizes that our forgetfulness is exponential, with a much larger rate of forgetting in the first hour than the rest of the first day.  As far as I know, this research was conducted by asking subjects to remember as many nonsense syllables as they could, and the graph shows the average rate of forgetting those nonsense syllables over a period of a month.

There are a few things to note here:
1) It is much easier to remember organized information than it is to remember nonsense syllables.

2) Every human is different and thus, this graph is merely an estimation of an average and not necessarily representative of every person.

That said, we can still make some generalizations according to this graph.  First, the graph shows that cramming can, in fact, be effective.  Discarding sleep as a factor for now, it seems that cramming up until 20 minutes before a test can yield a roughly 58% retention rate.  If you happen to cram the night before, it looks like you can still retain roughly 35% of what you studied.  Better than nothing, right?

Further research shows that a higher degree of original learning yields a lower degree of forgetting.  This supports exactly what your teachers and parents and tutors have all told you: starting to study several days before an exam is more effective.  Though you tend to forget more over time, the repetition of learning (e.g. studying days before a test) is like the generation of a new graph each time, and if you're already remembering 20-25% coming in, the amount that you have to learn gets smaller each time.

So let this research be further support as to why you should start studying days ahead of your exams.  As a side, I've also heard (and experienced) that studying for short bursts of time is more effective than continuous hours of work.  Thus, it's recommended that we attempt to have focused study for 30 minutes, take a 10-15 minute break, and repeat.  Our brains can experience information overload, which is why a 6-hour marathon study session can be ineffective and inefficient.

All of that said... I'm off to start studying for my exam that's tomorrow.  Oops.