Unironically, yes. The brain is really weird about a lot of shit. It’s not that difficult to make it believe something if you’re committed.

I got involved in this around a decade ago learning a bunch of “brain hacking” stuff. Can confirm, it is real. Can’t say it’s something I’d recommend to the average person, though. It’s a fast track to some major instability if you aren’t used to playing around with your own thought processes in detail.