Being tested for a concussion? Trying to convince a police officer you’re not high as a kite? This won’t really help you – normal people can’t do it anyway. It’s rarely used as a “brain works” thing, especially if an authority figure asks, they’re just rattling you a bit. If you decide to squarely designate yourself “the kind of person who obviously practiced reciting the alphabet backwards”, be sure to follow up by further segmenting that to “by that I mean geek, not drunk/druggie”.
But, either way, if you want to say the alphabet backwards, here’s a way to mnemonic it. It’s partly by some guy on reddit, partly me adding stuff back in that I forgot over and over.
When first asked, your try will probably be “ZYX”. Good job, like most people, you know the last three. If not.. learn them.
Next, we’ll name two states – West Virginia and Utah. Their abbreviations are “WV UT” which are the next four. I don’t have a universal reason those are the two states, but if nothing else perhaps you can eek out “W” as the fourth from last (before X) and thus go “Oh yeah, WV. UT”.
Next, the phrase “It’s our cue, pee on Martin Luther King Jr”. This is not recommended behavior, nor is it any reflection on his legacy. It’s merely a sentence that has the appropriate letter sounds – “tS R Q P on MLK Jr”. Since you’ll have forgotten the order of things, it actually overlaps by a letter – you just said “UT”, so peek at your own prior answer and go “starts with T. Oh yeah, iTS R Q..”. The main tripup is feeling that “cue” should have something like “to” after it (perhaps notice that you just said T) and that Jr only stands for J, (MLKJ, nor MLKJR). Again, it might help that you said R just then, by the “its”.
Next, do a jihg (and misspell it with h) because you’re fed up (or chased by feds, if you wish). Again, one letter overlap – with any luck the “MLKJ” will lead you to “J.. oh yeah, JIHG.. FED”.
There’s no overlap for the next bit. In fact there is no next bit – you are here supposed to realize you said “D”, and through sheer brainpower figure out that “CBA” is the finishing three. In summary:
ZYX (think of how it ends..) WV UT (West Virginia, UTah) SRQPONMLKJ (t-> It’s our cue, pee on MLK Jr) JIGH FED (j->do jig with bonus h, because fed up) CBA (d->that’s hella early in the alphabet – I’ll reverse ABC live)
Practice a bit and you’ll convince yourself you can do it. Try it again in a few days or hours (set an alarm or something) and patch what you ended up forgetting after all. Try again in another same unit (day, hour) if it’s still there, do another in a week. Two of those, and done – stuck forever. It may well be that you just remember it in a day, then in a week, and realize this whole exercise was sufficiently absurd to stick it in your brain. Go forth and wait years for a situation where you might be able to earn bragging rights with it, hope it’s still there by then.
If you actually manage to do it enough times to make the sentences and words fade out (like you were supposed to do with the alphabet song, but it never happened and you still have to start singing it to access alphabetic order) knowing it actually has real live uses if you deal with alphabetized data (like a library, or the herbal supplements at walmart) – you’re often presented with “You’re on M, need to go to F, how far is that?”. It’d be better to actually know the alphabet as a non-sequential thing, like knowing the ordinal for each letter (A=1 B=2 C=3 .. but so that you can do ordinal->letter->ordinal in arbitrary order, not by singing and counting) but a solid compromise is being able to do both “F..GHIJKLM.. six more between” and “M..LKJIHGF.. six in the other direction”.