Did anyone really think there was serious proof that all those blonde jokes were true? Probably not.
Then last year, scientists confirmed it: our hair colour is completely unrelated to our personality and intelligence.
So while we can now say definitively the genetic mechanism that controls blonde hair, for instance, doesn’t alter the biology of any other part of the body or brain, it still won’t stop us making assumptions based purely on hair colour.
And quite rightly so.
Because while it’s true the colour of hair we’re born with doesn’t dictate how bright, flighty or flirty we are, the colour we choose to be speaks volumes about how we’d like to be seen.
We know if we’ve got dark hair, we’ll be seen as more serious than someone who’s blonde, who’ll score high on sex appeal but not so great on intelligence or friendliness.
If every redhead got a dollar each time someone blamed an emotional outburst on their hair colour, most could retire by 40.
Every time we reach for a bottle of hair dye or instruct our hairdresser to add streaks of sunshine or warm, winter lights, we’re effectively tweaking our personality.
Our hair colour changes how others see us and treat us - and how we feel about ourselves.
When Times columnist and brunette Caitlin Moran pulled on a peroxide white wig for a fashion shoot, she said she not only felt ‘dangerously splendid’ she “could already see that being blonde would change my life: that my hair would want to take me out to places and be noticed.”