That's the prevailing tone as the nation enters the semiannual wallow in conspicuous consumption and obligatory obsolescence known as the fall fashion season, with its palette of "new" shades: a stupendous boon to a woozy economy, but potentially the greatest mental-health hazard since the Bee Gees.

Think of it: Science has shown conclusively that the colors we wear have the most profound and intimate relation to our psyches and our effect on others. Yet we dutifully cede control over them to a handful of cigar- sucking satraps from Seventh Avenue.

And how do these oracles choose the hues that will shape our mood? On little more than blind caprice: a fuddled combination of weavers' whimsy, designers' fantasies and the transient spasms of pop culture. Punk, funk, disco, retro--even a new movie "gives a new handle" for colors, says Bernie Ozer, vice president of the behemoth Associated Merchandising Corp. "It gives 'em the adrenaline." Just as we can thank "Brideshead Revisited" fetishism and "Chariots of Fire" for last year's mossy-tweedy rack binge, and "Flashdance" for the current rash of denuded clavicles, Ozer thinks "An Officer and a Gentleman" could cause a sartorial stampede to blue and white.

Which is fine if you want your visual identity dictated by a cologne-sodden French eccentric or some coke-nosed dandy in Beverly Hills. If not, the following principles may help in finding a color scheme that is suitably yours. Here's Looking at Hue, Kid

First, know whether you're coming or going. To the human eye, longer wavelengths (the "warm" hues of red, orange and yellow) appear to advance on the viewer; shorter waves ("cooler" greens, blues and violets) seem to recede. Each group has measurable physiological impact: Exposure to the Warms raises blood pressure, pulse rate and body temperature; Cools have the opposite effect. In a red-light environment, muscle reactions are significantly faster; and young rodents irradiated with red light experience abnormally rapid growth. (Swell for rat-ranchers--but, um, what's that noise in the darkroom?)

Colors also alter perception. In red light, lengths appear longer, weights feel heavier and time seems to pass more slowly; under green light, the effects are reversed. (On a boring date with a 7-foot tubbo? Consider the Arboretum!) One noted color therapist manipulates patients' fantasies by using the word "calm" written in green, "serenity" in dark blue, "courage" in red. Another advises warmish hues for the depressed. Blue has been prescribed to cure headaches, nervous hypertension and chronic insomnia. One intriguing anomaly: West Coast jails are wall-testing a shade called Baker-Miller Pink, which seems to make prisoners more tractable and less anxious.

And your wardrobe can control the mood of your associates. Albert Mehrabian, professor of psychology at UCLA, says it's a function of three factors: hue, level of arousal and dominance (see below). The most pleasing colors, in order, are blue, green, purple, red, orange and yellow. To enhance the effect, increase saturation and brightness. The arousing hues are ranked red, orange, yellow, violet, blue and green; amplify the impact by raising saturation but lowering brightness. Combine high pleasure with high arousal to produce "excitation or elation" and high pleasure with low arousal for a "comforting, relaxing impact." Unpleasant, high-arousal colors "make others feel discomfort, distress or even anxiety"; and low-pleasure, low-arousal colors are just "boring or depressing." In addition, Mehrabian says, "greater complexity, variability or novelty of design make for a more arousing impact." Got it? That's just the beginning. Case History No.1

You're a 26-year-old female publicist looking to hook Mr. Right, an engineer who's taking you to an outdoor restaurant. He's a solid, conventional guy who thinks men should take the initiative; you're a frisky soul who opts for a green plaid skirt and orange sweater and hopes for a post-prandial frolic at the disco.

Your relationship is doomed. For one thing, studies show that orange, red and yellow tend to stimulate appetite (hence the decor of most fast-chow joints). Thus, on top of the tension your colors have already caused him, your get-up could drive the boyo to gorge himself insensate, leaving you with the check, a Bromo nightcap and a lesson in the Heimlich maneuver.

For another, you're way off the chromatic norm. Research by costume consultant John T. "Dress for Success" Molloy indicates that American men prefer women to wear (in order of preference) pale yellow, beige, pale pink, navy, black, white, rust, tan and red. First choice for sexy lingerie is red; black is second. And he found that gents were turned off by ladies in gray, green, bright yellow, orange, mustard and--with the exception of accountants and engineers--lavender. Sales bear this out. Ozer says that orange, yellow and green are always tough to sell, whereas "shades of purple or grape are always good." (Perhaps this is why, in fashion argot, orange and yellow are colors that dare not speak their names, appearing instead in exotic synonyms: coral, mango and marigold; maize, platinum, curry and mustard.)

Moreover, your get-up is wrong for his job. Molloy's studies show that you have to adjust your color to your catch. Scientists, engineers and accountants prefer solid, conventional colors and dislike patterns. (And you look like a pile of luau leftovers!) Old-money types want "the classic upper-middle-class" combinations--blue and beige, beige and gray, blue and gray. If you're after a blue-collar fella, go monochrome, he says. For lawyers, blue, beige, white or pale yellow. Men in high-risk occupations prefer women in low- risk color schemes and yearn for blue, soft beige, rust and nonaggressive pastels. Professors are into rumples and earth colors; artists and musicians go for hot reds, oranges, yellows and greens. Dentists, Molloy found, are hopeless: "Almost nothing turned them on."

And if you had made it to the disco? Worse yet. A famous Soviet study concluded that when subjects were bombarded with sound vibrations, their ability to perceive red and orange diminished, but sensitivity to green and blue increased. Three spins around the floor in that sweater, and you would have disappeared like Judge Crater.

Now the good news: You're wearing the right stuff for an outdoor eatery. Insects are less attracted to yellow, orange or white objects. But watch the swatting from your co-diners in dark blue, red or brown. Case History No. 2

You're a 38-year-old male mediator called in to handle a contract squabble between the elderly owners and disgruntled employes of a restaurant. Hoping to relax both sides, you wear an old brown tweed suit with a pale lilac shirt and dark maroon foulard tie--acceptable, you trust, to the lady you're meeting for drinks later.

Without exception, everybody thinks you're an odious geek.

For openers, your suit is a loser. Molloy insists that dark gray and navy inspire respect and credibility in the upper middle class; whereas gray and pin stripes provoke bad vibes with lower middles, who respond best to solid blue. And brown, though a familiar Reaganism, turns every sector off and is "one of the worst suits made and should be avoided," Molloy says.

Your shirt is also wrong: Wear white to inspire confidence in men over 50. And foulard ties, unlike other sorts, are redolent of the Ivy League, which may irritate groups prone to class resentment.

For your date, you had the right idea. Although Molloy says that most women are attracted to navy and maroon, it's also true that "men who wear bright shirts with dark suits, and bright contrast26-year-old feming colors are considered clever," and "men wearing bright red ties are quite sexy." (Rodney Dangerfield, call your service!) But you blew it with the shirt. Real men don't wear purple, says Jack Hyde, head of the menswear design and marketing department at New York's Fashion Institute of Technology. The industry found this out after the pink- shirt craze of the "Ivy" '50s "dropped dead as soon as everybody had enough." When merchandisers tried to cozen gents into lavender, disguising it as "helio," they found that "men didn't like it no matter what you called it." Last year's epicene delirium over heathers and plums was a temporary Anglophiliac aberration. Wide World of Color.

To psychologists, that's not surprising. If the symbolic significance of colors varies from culture to culture, human preferences do not. Environmental psychologist Robert Sommer studied color associations and found, "In ancient Tibet, north was yellow, south was blue, east was white, and west was red. In Ireland, north was represented by black, south by white, east by purple, and west by a dun color." Yet color expert Faber Birren writes that "color preferences are almost identical in human beings of both sexes and all nationalities and creeds." In order of popularity: blue, red, green, violet, orange and yellow--"the eternal and international ranking"--for adults, that is. One researcher found that yellow is the most fascinating color to infants; but as children age, they lose their liking for it in favor of first red, then blues and greens.

Another study argues that blonds prefer blues and brunets reds because of genetically dictated differences in eye pigmentation. Nordic races become green- sighted from thin light; Latin and tropical races develop red sight from bright sun. Both, however, readily accept purple--the blending of red and blue.

Of course, color appeal varies with with context. As Leatrice Eiseman points out in Alive with Color, it is no accident that fabric softeners are packaged in soft pastels and artificial sweeteners in cotton-candy pink. Yellow houses, with their subliminal suggestion of sunny optimism, sell better than any other color. And the most popular jellybeans are red and black. Least favorite: white and purple. Case History No. 3

You're a 32-year-old female systems analyst having a job interview with a suburban computer firm. You've clad yourself in the latest charcoal power-duds, cranking down the pleasure-vibes until you look as ruthlessly competent as a sand shark. That's safely within Molloy's prescription: Navy blue or gray skirt suits for Washington and other tory venues; elsewhere beige, camel, black, dark brown, deep maroon and rust. And nix on pastels, pink, yellow, red, orange and lavender.

That's just the toggery to fit the third of psychologist Mehrabian's color-affect factors--dominance (vs. submission). Since the tone of those staid grays and stately black- and-white pairings is "associated with formality and rigid adherence to conventions," he says, "its impact makes the wearers seem more dominant. Because it has a more restraining effect on others around them, they (the wearers) become the more dominant stimulus."

But the last thing these cybernetic explorers at your job interview are looking for is rigid adherence and restraining effect. They hire a slovenly ding-dong wearing something that looks like a paisley pup tent. You get the boot.

Of course, anyone discomfited by the current I-Got- Mine recession-beater look can simply wait around. The cycle, says Ozer, takes about four years: one to get from European shows to mass merchandisers, and three to run its course. "Colors don't switch, they evolve. A gray could start in flannel, then evolve into sweat fabrics, and become heather the third year."

It may even take longer in tory Washington, one of the "more urban, sophisticated cities which wear darker colors. Or, you can simply opt out of the whole ritual. And tacontrast26-year-old femke comfort in recalling that classical Greece, which went 900 years without a major fashion change, managed to produce Homer, Aristotle and Pericles --and not a single Aubergine, Claret or Teal.