kitchen table math, the sequel: Ebbinghaus' forgetting curve

Wednesday, August 6, 2008

Ebbinghaus' forgetting curve

(full-size figure here)

I've always wanted to know this!

PaperToolsPro explains the chart:

The Ebbinghaus Forgetting Curve reveals that we forget new information rapidly unless we review it.

After 20 minutes, we recall 58.2%

1 hour 44.2%

9 hours 35.8%

1 day 33.7%

2 days 27.8%

6 days 25.4%

31 days 21.1%

SuperMemo is in my future, but I haven't figured out which one.

I'll probably have to try the online version, depending on whether I can figure out the user interface.


G Johnson said...

Wikipedia and other places you can google have more on this. This includes the fit R = e^(-t/S), where R is retention, t is time, and S is "strength of memory". The specific "after 20 minutes we recall 58.2%" is for memorization of short nonsense syllables. I'd hope that connections to prior knowledge helps strength of memory--but I've not found any quick data on this curve for mathematics concepts and processes. Perhaps, like Ebbinghaus, we should record our own experiences!

Catherine Johnson said...

Hi Greg --

"Memorization with understanding" is the phrase I've taken to using lately, as I try to put these things into more usable form.

Apparently, when you encounter (or memorize) something you understand, your memory is much better. There seems to be universal consensus on this; Willingham says it (iirc), the SuperMemo guy says it, ed schools say it --- meaning is a major memory aid.

But I have no idea how much better your memory is when you're memorizing concepts or factoids or words you understand.