It is almost a century since the US economist George Taylor came up with the revolutionary "hemline index" - the idea that when the economy is good, women's skirts get shorter, and when times are hard hemlines fall. Now the fashion world has finally offered up an alternative indicator of the country's economic state. Cropped, bobbed or floor-sweeping, the length of women's hair may no longer be seen as a result of the vagaries of fashion, but as an accurate barometer of the nation's wealth.
Japanese researchers have found that when economies are doing well, women wear their hair long; when there is a slump, they cut it short. While many may be sceptical of forging a link between the disparate worlds of finance and fashion, that the current vogue for short hair comes at a time when the British economy is experiencing its biggest downturn for decades is proving too much of a coincidence for some to ignore.
"There could definitely be a pattern in the UK too," said Susanna Sallstrom-Matthews, cultural economist at the University of Cambridge and author of The Consumption of Beauty. "People enjoy fewer material pleasures in periods of recession, so want more visual pleasures, and there's more variation among short haircuts than long."
With the rising cost of living keeping shoppers off the high street, it seems the style-conscious among us are choosing to update their look in a more economic way – with an edgy haircut.
After more than a decade in which long, largely unstyled hair has been the order of the day – years in which the country was also enjoying uninterrupted economic growth – the current influx of short styles certainly offers more variety.
"Long hair was so popular in the 1990s, it was really dull ... I think we might be moving away from this conservatism in fashion now," said Caroline Cox, author of Good Hair Days: A History of British Hairdressing.
Meanwhile Robert Frank, author of The Economic Naturalist: Why Economics Explains Almost Everything, pointed out that "shorter hairstyles require more regular cutting ... The trend for shorter styles is a bit of a puzzle".
While model of the moment Agyness Deyn's edgy blonde crop has attracted the most attention this summer – and been imitated by celebrities and ordinary women alike – bobs are also proving popular.
"We are receiving a number of requests for an 'Agyness' from our more adventurous clients," said Tori Markham of high-street hairdressers Toni & Guy.
Deyn's crop may have been described by Vogue as "the haircut of the decade", but the eagle-eyed may have noticed that her style appears to have been borrowed from an icon of another era – 1980s model Jenny Howarth. With a snip of the scissors and a liberal application of bleach, Deyn has tapped into Howarth's punky, anti-establishment style – a look that also coincided with a recession.
A browse through the fashion annuals reveals numerous other parallels. Jean Harlow's sassy short style was the perkiest thing about the Great Depression of the 1930s; as economic prospects improved in the 1940s, hair got longer, was set and pulled back from the face in the "victory roll" style.
Such a vogue for long locks continued well into the Fifties, when the glamorous styles of the film actresses Elizabeth Taylor and Vivien Leigh were much emulated, while floppy ponytails were popular among younger girls.
"In periods of prosperity, people are busy, so they have no time to consume – or produce – beauty. In the 1950s the country was very prosperous, but terribly boring aesthetically," said Ms Sallstrom-Matthews.
This fashion for long hair continued through the 1960s and 1970s, with Audrey Hepburn's chic up-do giving way to the long, centre-parted hippy look.
"It is difficult, because in most eras you have more than one significant style. Late 1980s Britain had the short, punky look, but also the mainstream, big-haired Dynasty girls," said Ms Cox.
"Since the early 1990s hair has been getting progressively longer – so long that hair extensions became perfectly acceptable – and now we're having to go short. Long hair has started to have connotations people don't want, like footballers' wives."
While the huge power of celebrities to spark, or to extinguish, a trend cannot be underestimated, the jury is still out on whether other economic forces might be at work here too.
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