A model poses in front of a Z-one car by South-African producer Perana designed by Italian design company Zagato during the first media day of the 79th Geneva Car Show.

London - Draping a model seductively over the product on sale has long been a ploy beloved of advertisers.

But now scientists claim they have discovered exactly why sex sells - and it isn’t just because consumers think that if they buy the car they can get the girl.

Researchers found seeing an attractive man or woman in an advert excites the areas of the brain that make us buy on impulse, bypassing the sections which control rational thought.

The scientists, from the University of California, monitored the brain activity of 24 adults while they were shown a series of adverts. Some employed “logical persuasion” (LP) - straightforward lists of facts about the product - while others used “non-rational influence” (NI) - such as an image of a woman leaping over a fire hydrant as it sprayed.

The results, published in the Journal of Neuroscience, Psychology and Economics, showed that the LP adverts provoked significantly higher levels of activity in areas of the brain involved in decision making.

Study author Dr Ian Cook said: “These results suggest that the lower levels of brain activity from ads employing NI images could lead to less behavioural inhibition, which could translate to less restraint when it comes to buying those products.” - Daily Mail