"Woo" wasn't a good search due to the homonym, and "woo woo" led to lots of matches in stories of children imitating fire engine sirens, but adding "astrology" and "occult" as additional terms led to some useful matches.
On my first pass, the oldest reference I found was in Nicholas Evans' novel The Loop (1999), p. 244:
And anyway, being a woman in the macho world of wolf research was hard enough without everyone thinking you'd gone woo-woo, the term her mother used to scorn everything from astrology to vitamin pills. And in truth, although Helen didn't doubt there were more things in heaven and earth than could be seen with the aid of a microscope, on the woo-woo scale she was definitely at the skeptical end.Hey, it's even a book with a skeptical character!
Next, by adding "astrology," I found a slightly earlier nonfiction reference, Kate Bornstein's My Gender Workbook (1998), p. 121:
Don't get me wrong, I believe in a lot of woo-woo stuff. I'm a double Pisces with a Taurus Moon. I was born in 1948, the Year of the Rat. I use several I-Ching software programs on my computer, and I've been reading tarot cards for nearly thirty years.Not a skeptic, in that case.
Then, by adding "occult," another earlier nonfiction reference by sociologists of religion, James R. Lewis and J. Gordon Melton, in Perspectives on the New Age (1992), p. 3:
I also found that the characterization of New Age psychism as being "woo-woo" and "airy-fairy" was true of only some of the more public New Age channels.But then, pay dirt--a source going back to May 1844 that looks like a likely candidate for the origin of the term, in The North British Review, vol. 1, no. 11, p. 340, in a review of (or excerpt from?) Report by the Commissioners for the British Fisheries of their Proceedings of 1842, "Our Scottish fishermen" (pp. 326-365):
When beating up in stormy weather along a lee-shore, it was customary for one of the men to take his place on the weather gunwale, and there continue waving his hand in a direction opposite to the sweep of the sea, using the while a low moaning chant, Woo, woo, woo, in the belief that the threatening surges might be induced to roll past without breaking over. We may recognize in both these singular practices the first beginnings of mythologic belief--of that religion indigenous to the mind, which can address itself in its state of fuller development to every power of nature as to a perceptive being, capable of being propitiated by submissive deference and solicitation, and able, as it inclined, either to aid or injure.Though this isn't enough to be certain, this looks like a very likely origin of the term.
Thanks to Adam for prompting this search.
UPDATE: Josh Rosenau at Thoughts from Kansas points out a 1986 St. Petersburg Times story:
Are cookbook publishers that desperate? … This season they present us with two "new and unique" horoscopic cookbooks - A Taste of Astrology by Lucy Ash and Cosmic Cuisine by Tom Jaine - adding another dimension to star-inspired cookbooks.In the comments below, I point out two older cases of "woo woo" I've found in ghost stories as a sound:
Both authors are British (of undisclosed signs) but they are, most uncannily, on much the same woo-woo wavelength. They do not suggest casing out a potential romantic partner according to sign language.
Groff Conklin's 1962 The Supernatural Reader, p. 101 has these two sentences, but the page context isn't available from Google Books: "Someone else giggled, and from the darkness beside the building came a high-pitched, 'Woo-woo!' I walked up to Sam and grinned at him."
Cecil John Richards, Wind Over Fowlmere and Other Stories, 1953, p. 116: "...going 'woo-woo woo-woo-woo' in its deep gruff voice just over my head. ... And then Hargreaves led us once again into the realm of the supernatural."
UPDATE (May 7, 2010): Anton Mates found and posted this news item from 1984 at Josh Rosenau's blog and in the comments below:
THE NEW AGE SOUND: SOOTHING MUSIC BY SINCERE ARTISTS
Philadelphia Inquirer, The (PA) - Sunday, October 21, 1984
So who is this New Age audience? Mostly upscale folks in their 30s and early 40s, the ones weaned on Baba Ram Dass and Woodstock and hallucinogenics, macrobiotic diets and transcendental meditation.
George Winston, who practices yoga and who currently has three albums on the jazz charts (his five Windham Hill recordings have reportedly sold more than 800,000 copies; his LP December has just been certified gold), has jokingly called this crowd the "woo-woos." In a 1983 interview in New Age Journal, Winston, asked if he knew who comprised his audience, answered that there were some classical fans, some jazz, some pop and "all the woo-woos."
"You know," he added, "there's real New Age stuff that has substance, and then there's the woo-woo . A friend of mine once said, 'George, you really love these woo-woos, don't you?' and I said 'Yes, I do love them,' and I do. I mean, I'm half woo-woo myself."