Left to right: Dakota Fanning, Charlize Theron, Meg Ryan and Renee Zellweger. Click photo for their brunette versions.

In Hollywood as in life, blondes are said to have more fun.

But if you are looking for angst -- soul-baring, guts-spilling, Oscar-worthy angst -- grab a brunette.

At least that is one explanation for the recently darkened tresses of such A-list blondes as Charlize Theron, Renee Zellweger and Meg Ryan as they throw themselves into edgy roles.

Even tiny Dakota Fanning covers her fair-haired demureness with a dark wig to play a spooky kid in the movie "Hide and Seek."

"Darker hair is more sinister looking, more serious looking, more smouldering and calculating," says Brad Johns, the hair stylist and artistic director known for his blond magic at Avon Salon and Spa in Manhattan.

"Blond is more innocent but sexy, angelic but devilish, playful but a little silly," says Johns, a native of McKees Rocks who does Natasha Richardson's hair.

"You take home the brunette to your mother, but you go out with the blonde," says R.J. Sexton, owner of Atomic Hair Salon in Ross, quoting an expression. "Some guys are stupid that way. They love blondes."

Of course, these are mere stereotypes. There are plenty of examples of serious actresses, including Cate Blanchett, Meryl Streep and Kate Winslet, who have not had to turn to chestnut hair dye to take on meaty roles.

Plus blondes can pull off scary -- or downright psycho -- roles if they are ice-cold blondes, Johns said. Think of Glenn Close in "Fatal Attraction."

Sonni Abatta: Fleeing the blonde stereotype. Click photo for larger image.

But the sunny blonde/stormy brunette dichotomy is one that Hollywood executives have perpetuated over the years with varying degrees of subtlety.

Remember how in the TV sitcom "Bewitched," Elizabeth Montgomery went brunette to play Serena, the mischievous, bad-girl cousin to Samantha's blond good-girl witch?

That was about as subtle as her twitching nose.

Today, Zellweger, Ryan and Nicole Kidman have morphed into brunettes to play unglamorous roles that have acting oomph. Zellweger is playing a Depression-era wife of a boxer in the upcoming "Cinderella Man," Ryan shed her cute-as-a-button image to play a lonely brunette teacher in the gritty drama "In the Cut," and Kidman went brunette and big-nosed to be a suicidal Virginia Woolf in "The Hours." And Reese Witherspoon won't be legally blond to play Johnny Cash's wife in the upcoming "Walk the Line."

Then there's Theron, whose raven hair set off her dark blue dress at the Golden Globes. She has gone dark to play an amoral secret agent in the upcoming movie "Aeon Flux," a live-action version of an anime series.

"Our culture still carries very, very deep metaphoric values of dark and light," says Robert Thompson, a media and popular culture professor at Syracuse University. "We call them 'dark roles.' I suppose dark roles call for dark hair. In westerns, the bad guys wore the black hats and the good guys wore the white hats. This kind of metaphoric thinking can do some bad stuff. In unconscious ways, it can apply to race."

Thompson said Hollywood directors sometimes shy from a blonde in a dark role because "the stereotype of the real pretty, traditional American ideal of blond beauty carries such baggage that it would take the first 40 minutes of the movie to just downplay it. It's not worth the trouble." A brunette also will bring more audience empathy, he says, than a young blonde.

Lucy Fischer, director of the film studies program at the University of Pittsburgh, said, "I don't think anyone has to dye one's hair to be taken seriously anymore." The over-the-top parody of the "dumb blonde" still operates for laughs in movies such as "Legally Blonde" but is no longer the norm.

Fischer said actresses sometimes dye their hair to distance themselves from a romantic comedy image. Ryan moved from buttercup blonde in "Sleepless in Seattle" to mousy brown teacher in the dark thriller "In the Cut."

"Meg Ryan's career is in trouble," Fischer said. "The romantic comedy wasn't playing so well after the breakup of her marriage. ... Women have more image problems as they age," especially if they have been known for feel-good comedies.

Dark hair is also a great attention getter. It's not just actresses who are jumping on the brunette bandwagon. Britney Spears, Nicky Hilton and Ashlee Simpson have gone darker, too.

So has Sonni Abatta, KDKA-TV reporter. Her new darker hair is close to her natural color.

"I consider this my social experiment and an effort to look more natural and get away from the blonde stereotype," Abatta said.

"You are treated quite differently, mainly when you are out at bars or in clubs," she said, although she has noticed no difference at her job.

But some of her viewers are clamoring for the old blonde Sonni back. "I am getting a lot of angry callers. 'We hate her.' "

But she laughs and thinks she looks more natural as a brunette.