In fashion terms, the rule of hair couldn't be more simple: the bigger it is, the richer you are.
Glossiness, high shine and tamed flyaways – these are all by the by: time was, you were nobody until your hair took up most of the room. Thankfully, 'dos have deflated a little in recent years, with stars and stylists opting for a more natural look. They've been using minimal products, and called an amnesty on the lungfuls of hairspray and the scalp-punishing back-combing of yesteryear.
But big hair has made a comeback, appearing most recently above the smiling faces of fashion luvvies Cheryl Cole and Sarah Jessica Parker. After so many seasons of sleek blow-drys and elegant chignons, their riotously bouffant locks, primped and oomph-ed, were shamelessly redolent of the lacquered coifs of the Sixties and starchy 1980s power 'dos.
It has something to do with X Factor, of course – what doesn't these days? But Cole, the well-beloved Geordie sparrow, has flown the nest and taken a spot as judge on the American version of the TV talent contest. It was at her first public appearance for the show that her enormous new hair-style blocked out the sun, or stole the limelight at least.
Big hair is an essentially American trope, conjuring the healthy, bouncy athleticism of the pre-war outdoors movement, which was revisited to honeyed and golden effect in the Seventies. The Sixties take on the style was more structured, developing into ever more towering beehives, as sported by the likes of Twiggy and Dusty Springfield.
In the following years, big hair of the afro variety became a means by which black women could assert their autonomy, refusing to have their locks chemically straightened or braided into more "tamed" styles. Later incarnations in the Eighties reimagined the aesthetic by way of synthetic products, with hair becoming larger and larger until it practically threatened to engulf the burgeoning yuppie culture.
Big hair, sprayed and stiffened until it became almost a helmet, was a must-have accessory for women shouldering their way into the workplace during the ultimate "power" decade. Any natural resonances disappeared under a weight of curling tongs and diffusers, as the look became hyperbolically styled and structured.
And this is what Cole has been channelling, as she attempts to mark her territory as Queen Bee on the X Factor judging panel. No woman should go into battle with flat hair, and it's no coincidence that Paula Abdul, her rival on the show, has a bouffant too.
Of course, the other reason for the perennial popularity of the trend is that it makes you look thinner. Starlets usually rely on enormous handbags for this effect, but the directive this season is a clutch bag or nothing, so red carpet attendees are putting their faith, and neuroses, in the eternal power of big hair.
Everybody's favourite Geordie miss, Cheryl Cole makes the transition to Stateside by ratcheting up her hair several notches. After all, everything is big in America. She told British press she was taking a suitcase full of HobNobs with her; perhaps they contain some special sort of follicle-stimulating nutrient.
The doomed queen elevated hair to heights not seen before or since. Her towering do consisted of hair powdered and pinned over padding and wire frames, decorated with fruit, feathers, figurines and stuffed animals. Servants had to walk behind her holding a pole to keep the hair upright.
The model and actress was the coolest thing about the Seventies, and her hair took centre-stage. Her enormous afro has become iconic in its own right, symbolising Black Power and a new sort of ethnic elegance. And, it proved a brilliant hiding place for love-struck rock stars such as Mick Jagger and Marc Bolan.
Model Marisa Berenson had fashion on her side – her grandmother was the designer Elsa Schiaparelli. With her doe-like eyes and rosebud mouth, she was the perfect poster girl for the Seventies incarnation of big hair – and has been much cited on the catwalks this season by designers looking to channel some of her preppy-girl cool.
Everything about the supermodels was big – their eyes, lips, breasts, hair and paychecks. Crawford, with her God-given tawny limbs and abundant locks, was the most obvious ambassador for Eighties big hair, which was blow-dried into huge, sweeping cowlicks, and back-combed to within an inch of its life.
Sarah Jessica Parker
A naturally curly girl, Parker has previously favoured a voluminous blow-dry – but nothing yet of these proportions: now it looks like it lifts off in one piece. No doubt she's referencing the disco 'dos of Studio 54, which was so closely linked with the Halston label of which she is creative consultant.