I am beginning to suspect that it is surprisingly common for intelligent, competent adults to somehow make it through the world for a few decades while missing some ordinary skill, like mailing a physical letter, folding a fitted sheet, depositing a check, or reading a bus schedule. Since these tasks are often presented atomically - or, worse, embedded implicitly into other instructions - and it is often possible to get around the need for them, this ignorance is not self-correcting. One can Google "how to deposit a check" and similar phrases, but the sorts of instructions that crop up are often misleading, rely on entangled and potentially similarly-deficient knowledge to be understandable, or are not so much instructions as they are tips and tricks and warnings for people who already know the basic procedure. Asking other people is more effective because they can respond to requests for clarification (and physically pointing at stuff is useful too), but embarrassing, since lacking these skills as an adult is stigmatized. (They are rarely even considered skills by people who have had them for a while.)
This seems like a bad situation. And - if I am correct and gaps like these are common - then it is something of a collective action problem to handle gap-filling without undue social drama. Supposedly, we're good at collective action problems, us rationalists, right? So I propose a thread for the purpose here, with the stipulation that all replies to gap announcements are to be constructive attempts at conveying the relevant procedural knowledge. No asking "how did you manage to be X years old without knowing that?" - if the gap-haver wishes to volunteer the information, that is fine, but asking is to be considered poor form.
(And yes, I have one. It's this: how in the world do people go about the supposedly atomic action of investing in the stock market? Here I am, sitting at my computer, and suppose I want a share of Apple - there isn't a button that says "Buy Our Stock" on their website. There goes my one idea. Where do I go and what do I do there?)
Strictly speaking, the weight of an individual can fluctuate even in the course of a day, due to the consumption or excretion of fluids. It can fluctuate more permanently when you lose or gain body mass in the form of fat or muscle.
I'm under the impression that, in contrast, measured I.Q. of an individual is supposed to stay more or less within the same approximate range throughout the course of that individual's life (with obvious caveats for brain damage, senility, and as you say, exceptional individuals at the extremes of the distributions).
From what I know, there are high correlations between an individual's IQ test scores at different times, especially in the short run. Depending on the study, it ends up being something like 0.95 in the short run and 0.7-0.9 between different ages (I'm just quoting rough ballpark figures from memory -- they of course differ between studies and age spans). Some impressively high correlations were found even in a study that compared test scores of a group of individuals at 11 and 77 years of age.
On the other hand, people can be coached to significantly impro... (read more)