gfish: (Default)
gfish ([personal profile] gfish) wrote2010-10-08 02:41 am

Learning curve

"It has a steep learning curve." This is, assuming we share a cultural background, a phrase you will be familiar with. But have you ever tried to figure out what it means? What exactly does the curve in question graph?

Well, a steep learning curve means something is difficult to learn, particularly as you get started. That simply means lot of time and effort has to be expended to gain a small amount of proficiency. So until t gets large, the output of the function stays fairly small. Let us see what that might look like.



But... that isn't very steep at all! (At least not early on, when it counts. The rest I was just being fancy with because a linear plot is dull.) And if we look at one that actually is steep, it's even worse.



Now a small amount of time and effort results in a very large amount of proficiency! That's the exact opposite of what we want! The only way we can fix it is if we invert the axes.



We've finally found the shape we want, with the interpretation we want. But at what cost? AT WHAT COST? We have made time a dependent variable! The natural order of nature itself must be turned upside down in order to satisfy the logical demands of this seemingly innocuous little saying!

(For certain tiresomely literal people in my audience: I am perfectly aware there is no grand universal rule preventing this from being done. But it's weird and uncomfortable and completely at odds with the intuitive nature of the original saying.)

Conclusions: Steep learning curves are actually quite shallow, and shallows ones steep. Whoever invented this metaphor did not work with graphs very often. And from now on, if something is difficult to learn you should say it has a very shallow learning curve!

[identity profile] zzyzx-xyzzy.livejournal.com 2010-10-08 10:25 am (UTC)(link)
There are a so many different kinds of graphs you can make and have been made in the study of memory that it's entirely unclear what the "steepness" in the common phrase refers to.

However the first plots of "learning curves" were by Ebbinghaus, who among other things graphed the number of syllables of nonsense words on the horizontal and the number of repetitions required to memorize words of that length on the vertical.

[identity profile] dymaxion.livejournal.com 2010-10-08 11:09 am (UTC)(link)
It's often effort, not time. Making effort a dependent variable is less bad.
solarbird: (Default)

[personal profile] solarbird 2010-10-08 03:23 pm (UTC)(link)
Yes, this. It's effort.

[identity profile] sistawendy.livejournal.com 2010-10-08 03:58 pm (UTC)(link)
Go to bed, Fish.

[identity profile] avhn.livejournal.com 2010-10-08 05:29 pm (UTC)(link)
I've graphed this before and came to the conclusion that if I just looked at it upside down, all would be well. It's just my perspective that's off.

[identity profile] gfish.livejournal.com 2010-10-08 05:32 pm (UTC)(link)
I suppose doing things while standing on your head does tend to make it more difficult...

[identity profile] tithonium.livejournal.com 2010-10-08 05:36 pm (UTC)(link)
I agree with those above saying it's effort. But either way, it's a question of expense to reach a given level of proficiency. So even if you're talking about time, time is still the dependent variable. the dependent variable is what you're measuring in terms of the other, and 'steep learning curve' implies that a lot of [y] is required in order to learn [x]. I disagree that 'time' is 'naturally' the independent variable. It just /frequently/ is, because it's usually what one is measuring in terms of.
Edited 2010-10-08 17:37 (UTC)

[identity profile] adularia.livejournal.com 2010-10-10 05:01 am (UTC)(link)
What are you thinking in the negative range of time? Procrastinating?

[identity profile] tereshkova2001.livejournal.com 2010-10-10 11:07 pm (UTC)(link)
This doesn't address the idiom "falling off the learning curve" either, which always gives me an image of someone rock climbing up a graph.