ACUMEN  
        The Art and Science of Learning Craft  

 
 

 



Forgetting Curve


The forgetting curve illustrates the decline of memory retention in time.

In 1885, Hermann Ebbinghaus discovered the exponential nature of forgetting. The following formula can roughly describe it:

 

Where R is memory retention, S is the relative strength of memory, and t is time.

Ebbinghaus studied the memorization of nonsense syllables, such as "WID" and "ZOF". By repeatedly testing himself after various time periods and recording the results, he was able to describe the shape of the forgetting curve.

The forgetting curve describes the exponential curve that illustrates how fast we tend to forget the information we had learned. The sharpest decline is in the first twenty minutes, then in the first hour, and then the curve evens off after about one day.

The speed of forgetting depends on a number of factors such as the difficulty of the learned material (e.g. how meaningful it is), its representation and physiological factors such as stress and sleep. The basal forgetting rate differs little between individuals. The difference in performance (e.g. at school) can be explained by mnemonic representation skills.

Basic training in mnemonic techniques can help overcome those differences in part. The best methods for increasing the strength of memory are:

  1. better memory representation (e.g. with mnemonic techniques)
  2. repetition based on active recall (esp. spaced repetition)

Each repetition in learning increases the optimum interval before the next repetition is needed (for near-perfect retention, initially repetitions may need to be made within days, but later they can be made after years).

The speed of forgetting depends on a number of factors such as the difficulty of the learned material (e.g. how meaningful it is), its representation and physiological factors such as stress and sleep. The basal forgetting rate differs little between individuals. The difference in performance (e.g. at school) can be explained by mnemonic representation skills.

In a typical schoolbook application (e.g. learning word pairs), most students remember only 10% after 3–6 days (depending on the material Therefore, 90% of what was learned is forgotten.

A typical graph of the forgetting curve shows that humans tend to halve their memory of newly learned knowledge in a matter of days or weeks unless they consciously review the learned material.

A formula and the case for making time to review material: Within 24 hours of getting the information - spend 10 minutes reviewing and you will raise the curve almost to 100% again. A week later (Day 7), it only takes 5 minutes to "reactivate" the same material, and again raise the curve. By Day 30, your brain will only need 2-4 minutes to give you the feedback, "

                                                                                          Spacing Effect
 




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