When I was growing up, this was a word kids would use when tormenting someone by pretending to offer something the other kid wanted, then yanking it away. I learned the use of it long before I read/knew a word like “psychological”, so I always wondered how that might have entered the lexicon. This would have been from the late 1970s in New York City.
I can cite a well-known Eddie Murphy stand-up routine from around 1983, where some kids taunt another kid who didn’t get any ice cream with “want a lick? – PSYCHE!” So it can’t have been a completely local thing. (Though Murphy did come from my neck of the woods.)
On the flip side, I wonder when it disappeared from the lexicon. My teenaged kids say they’ve never heard anyone say this, and I still live 10 blocks from where I grew up.
The television show, “Psych” got it’s name from just this usage (and a pun on “psychic”), so it’s not very long gone (it’s only been off the air a few years).
As I recall “psych” is short for “psych out” which had been used back into the 60s to mean “undermine someone’s confidence in order to defeat them.” It seems straightforward to shorten that to “psych” and alter the meaning to refer to fooling someone in any way.
" b. To gain a psychological advantage over; to intimidate, demoralize. Usu. with out. Cf. psyched adj. 1.
1963 Amer. Speech 38 205 Get psyched out, v. phr., slang term applied to losing one’s nerve while skiing downhill.
1971 E. Bullins in W. King Black Short Story Anthol. (1972) 63 Dandy thought that the way she managed things and worked the love and affection from people was like a pimp who psychs out his whores.
1976 J. Quarry in 6,000 Words 165 Pressure doesn’t psych me.
1977 I. Shaw Beggarman, Thief iii. ix. 318, I could see something was psyching him out and it worried me.
1989 Indian Bookworm’s Jrnl. Spring 16/1 The crowd in ugly mood, surges against the frail police line…They’re all staring at you, trying to psyche you out.
2001 E. Colfer Artemis Fowl v. 99 You’re absolutely right. I have no clue what’s going on. So there’s no future in trying to psych me out."
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Hm. I never thought of this usage as a shortened form of “psych(ing) out”, which is more of a strategical advantageous “make him think left then you go right” ploy than a Nelson Muntz style “ha ha!”, but I guess it could be, on a very childish level.
This is how I remember it from the early-'70s, or maybe even the late-'60s. We’d trick/fool/‘undermine someone’s confidence’ and say, ‘Psych!’ We’d also say, for example, ‘Ooh did you see how Bill psyched out Bob at lunch? Outta sight!’
So basically, when you say ‘Psych’ to someone, you are informing that person that you have successfully performed a Vulcan/Jedi mind trick upon him or her.
My friends and I used this all the time in the mid-1970s in Willingboro, NJ (Philadelphia area). In general, it meant “Ha ha, just kidding!” Often used in the context described by the OP. My kids, born in the 1990s, who live just a few miles away from where I grew up, do not use this.
In the early 60s I understood “to psych” and “to psych out” to mean exactly the same thing. They’d mostly commonly be used in the form. “I psyched you out” or “You got psyched.”