Lev Vygotsky was a developmental psychologist who created a more nuanced model for thinking about a student’s skill level in a given subject area. Schools might traditionally think of Alice as having, say, a “7th grade math level” and Bob as having a “5th grade math level,” because Alice can do more kinds of problems than Bob can.
Vygotsky pointed out that often it makes more sense to think of any given student as having a “zone of proximal development” ie a range of “math levels” that they’re capable of performing at depending on the circumstances. For example, it may be that Alice can perform at a 7th grade level in the usual standardized testing circumstances; but if you give her a friendly partner to write things down on the paper for her, she can manage an 8th grade reading level. If you have that person ask her certain sorts of helpful questions (like in Polya’s How to Solve It), or help lay out the problem in her head, she can do even better. On the other hand, if she’s short on sleep, hungry, and using a calculator she’s not familiar with, Alice may only be able to do 6th grade level math. So we could say that Alice’s ZPD encompasses the 6th through 9th grade math levels (her “trailing edge” and “leading edge,” respectively)
The main point I’ve heard this used to make before is about the general value of providing “scaffolding” in helping people increase their skill level at a variety of tasks (such as having lots of scratch paper, plenty of time to think, or someone else writing things down for you). This applies in personal growth/development as much as anywhere else, but I think the model provides another useful insight in that domain: personal development work can be aimed at improving performance in either the leading or trailing edge.
Trailing edge personal development looks maybe a lot like crisis management (a la Ozy’s post) – reducing the terribleness of things that happen on your worst days, or improving your ability to manage to execute basic functionality in such situations.
Leading edge personal development reminds me a lot of what I think Eliezer has worked quite hard on in himself (though of course I don’t know him that well, so I’ve no idea if this is an accurate description) – to strongly optimize for what he can accomplish in a fairly small number of peak hours per week, and not worry too much about how much he’s able to get done the rest of the time.
Of course we can split these categories arbitrarily small – perhaps in particular it’s very common for personal development work to also target the middle of the ZPD, which looks like improving what you can do on an average day, in an average state – the place you inhabit like 80% of the time or whatever. It seems to me that Matt Fallshaw has done a pretty nice job of optimizing his average-day functionality.
I suspect that all of these things are good kinds of work to do for at least some people in some situations. I suspect it’s interesting to notice which kinds of improvement you tend to do, and to have this model in mind when you’re trying to do personal development (because the kind of work you need to do to push forward your leading edge may not serve you particularly well if what you’re actually trying to do today is shore up your trailing edge). It seems possible it also explains one dimension along which people’s self-improvement “styles” may differ in a way that I expect would make self-improvement skills very hard to transfer naively, but which may be a very easy “translation” to make if you’re consciously aware that you’ll need to do so.