The curious case of the forgetting curve

The learning curve is a common phenomenon we see in Knowledge Management. As an organisation acquires more knowledge, their performance increases as they "climb the learning curve".  However without care and attention, the curve can reverse, and become a forgetting curve. Here is a case history where that happened.

I have blogged before about our Bird Island exercise, probably the longest running KM experiment in the world, and about how it demonstrates in a very clear way that Knowledge management can drive performance.

It is like a lab experiment in KM, with very clear learning points.

We had an interesting twist to the game a couple of weeks ago, where we had two people in the class who had done the game before, about 6 months ago. Now you might expect that this previous experience and knowledge would give them an edge.  They ought to remember some of the key design principles from the game, and they should therefore be well ahead of the other teams based on this knowledge.

So I put these two people with experience into the same team, to see if this would happen.

Well, it happened to an extent. The two people remembered some bits and pieces, and these included some high level design principles, and a few tips and hints. However much of the other detail required to succeed had been forgotten over the intervening 6 months. They built a tower slightly taller than the other teams, but one third the height of their performance 6 months previously.

As one of them said in the debrief "a little knowledge is a dangerous thing".

The graph above shows their performance 6 months previously, where the 5 bars on the left represent how they gained knowledge through their previous Bird Island experience. The red line is the learning curve they went through in the game.

The greay bar on the right shows their performance 6 months later, built with the help of a hazy memory and "little knowledge" from the previous exercise.and therefore how much had been lost in the interim. The green line is therefore their forgetting curve.


This result reinforces recognition of the frailty of human memory as a long term knowledge store, and therefore the need to support that memory through some sort of capturing and recording. Even 6 months is too long to leave knowledge in memory alone. We need to be capturing it as we go, even as an aide memoire, otherwise we lose it.

Or even worse, we retain a little knowledge, and find that it is just enough to be dangerous.