Sneaky age filter? You must be young enough to remember your SAT scores.
I can remember mine just fine.
If you're really looking for smart people, use "Answer this word problem in two or more paragraphs. Write your answer on the sheet of paper provided. In cursive."
Not wanting to learn cursive is like not wanting to know lower case just because caps lock exists.
Doing this may well expose you to age discrimination lawsuits, since it's just sneaky indirect age filtering.
Another example would be if you required a minimum SAT score of 1601. Sure, someone could have gone off and taken the SAT as an adult or a young child but in reality it is mainly an age filter.
My kids are learning cursive in elementary school right now, FWIW.
By definition, people who know more things are smarter than people who know fewer things. That's just how it works.
For centuries, people have striven to improve themselves through the acquisition of knowledge and skills. It is a quirk of recent generations that so many members take pride in their lack of knowledge.
I'm repeatedly bewildered by my Millennial colleagues who proudly say "I don't know what that means," or boast "I don't know what that is" with no sense of shame.
Imagine, you have two people. Person A knows cursive, person B does not. Person B knows the ins and outs of Newtonian physics, person A does not.
Which person is smarter? Which person would the cursive test say is smarter?
What you seem to have mistook for people not knowing things without shame, is people valuing knowledge not by the preponderance of its quantity but by its total when multiplied by its utility.
Otherwise I do not envy the shame you must feel at lacking the knowledge of which plants are edible, how to.clean a carcass, how to fashion a needle from bone and an axe from stone, the mixture of clays to use to make your bricks, and all manner of other once-necessary tidbits whose usefulness has lapsed for the general population.
One could learn this skill in their 20s or beyond, but there's an opportunity cost – why not something else that would actually improve work performance, or that you enjoy doing?
I still wish I'd been taught in elementary school, though, because it would've been really useful as a student. Some of our teachers discreetly handed out practice booklets to students who'd "expressed interest" (their parents taught them the basics and teacher noticed); most of us were not so lucky.
Communication skills, teamwork skills...
How to cook better, maintain relationships better, keep a tidier space...
Not perfect! But time well spent.
But of course this is a lot of unnecessary steps compared to the usual method: length of work and education history +18 years.