The pitch is: haunted by the ghost of her lost love, Scottie forces Lucie to dye her red hair in platinum blonde. Thus, by this capillary metamorphosis, Lucie reaches her destiny: to transform into passional fantasy and, incidentally, to die.

You may not have seen "Sueurs froides" (1958), cult film by Alfred Hitchcock, but whether you like it or not, this scene serves the collective unconscious. The same goes for the screenplays of Jean Harlow and Marilyn Monroe for the brown-blond tandems of David Lynch's "Mulholland drive" or Woody Allen's "Vicky Cristina Barcelona". The sociologist Michel Messu, author of "An ethnologist at the hairdresser", confirms this: if today one woman out of three colors hair (38% of the under 40 have already done so), if the " tutos "and" influencers "cardboard on the Web, if the colors are seasonal as in fashion (the" bronde ", marriage of brown and blond, being cited as the" it "of the spring-summer 2014 collection) a thriving marketing field, the history of cinema is not for nothing.

The coloring of the hair, an identity game

Hobby at high risk in antiquity (the Romans had the smart idea of ​​poisoning themselves with metallic cyanide), a practice still marginal in the 50s (the fatal days when Marilyn Monroe burned the scalp), coloring is indeed democratized at the speed of lightning, surpassing its only utilitarian function (hiding the traces of age) to become a playground of identity open to all. "In a society marked by the cult of singularization, this game takes on an unprecedented scale," insists Michel Messu.

"But let us not forget that coloring has always been linked to the quest for behavioral attributes, which was, yesterday, the myth of the sweet blonde and the bristling, feminist brunette, an archetype inherited from romantic literature, still active in the popular imagination but which the twentieth century loved to divert. The cinema (still him) has blurred the values ​​attributed to colors, inviting individuals to play with several facets of their personality, " continues the sociologist.

Thus, under the effect of cosmetic innovations (activation by oil, end of ammonia ...), coloring has imposed for women as a common practice. In a few decades, it has lost its role as a sociocultural marker and its subversive dimension (the punk period). An invariant, however, persists: the fascination for blonde. An obsession that could be explained, according to theories, by the secular representations of Aphrodite, or, according to the Canadian anthropologist Peter Frost, by the fact that "sexual selection favors bright colors but also rare colors."

Last track: we would worship this color because the natural blonde would be doomed to disappear from the planet in the coming decades. A persistent rumor among geneticists working on the subject (it has never been confirmed by the World Health Organization) and which may have convinced more than one to opt this summer for the "blonding" .