I can't imagine pictures in my head, so regardless of how long I will think about pink elephant, you will see nothing.
For people like you, they can always fall back to the old "$5 wrench" method...
IMHO, thermorectal cryptoanalysis with soldering iron is much more effective for similar price.
OK. I'll just think about something else. I don't know why people think tricks like this work on anyone but the extremely simple-minded.
I don't know how your brain works, but for most people just hearing/reading the words "pink elephant" will cause their System 1 to immediately bring that concept into their consciousness.
This isn't "simple minded" it's just how brains work, and the alternative of having to actively think about a word to remember what it means, would be much slower.