Old Kaioshin describes his own ability as a psychic power:
Chapter: 479 (DBZ 285), P10.1-5
Context: Elder Kaioshin explains his ‘ability’
Elder Kaioshin: “With my psychic powers, I can take the hidden power which anyone has, no matter how amazing a master they may be, and draw it wa~~ay, wa~~ay out above their limits. Ehehehehe…Have you ever heard of an ability like that?”
Kaioshin and Kibito: “Oooh!”
Goku: “Wh-what?...Ain’t that the kind of ability you hear about fairly often?”
Elder Kaioshin: “Wh-what are you talking about…?! Above their limits! Above! There de~~efinitely isn’t anyone else that incredible! [ ] Hey, you over there, you were the one who pulled the sword out, right? Come over here a little. If someone could pull that sword out and swing it around, then once I get through with them they’ll de~~efinitely be able to become the best in the universe.”
It's also made to sound as though his technique is not different from that of MasterMolesterGuru's, merely that it goes beyond its capabilities. So it's fair to say that it's a psychic ability that Guru learned/created.