CORNY ads using bikini-clad babes to flog everything from cars to corn plasters are definitely here to stay, according to brain scientists who have discovered exactly why sex sells: it drives our brains to say, “What the hell,” when considering risky financial moves.

The study, in the journal NeuroReport, says that when young men are shown erotic pictures, they are significantly more likely to make a larger financial gamble than when shown neutral images such as an office stapler, or scary ones such as snakes. The research, performed by Brian Knutson, a professor of neuroscience at Stanford University, California, and Camelia Kuhnen, a finance professor at Northwestern University, Illinois, scanned the participants’ brains during the experiment using functional magnetic resonance imaging (fMRI).

The scans showed that erotic images and risky financial decisions boost activity in the same area of the brain, the nucleus accumbens. It appears that the stimuli reinforce each other, regardless of the fact that they bear no relevance to each other — just as a picture of a bikini-clad woman splayed on the bonnet of the car says nothing useful about the car’s performance or reliability. The link may be due to the fact that risk-taking, possession- grabbing and sexual conquest could all be linked in our ancient evolutionary brains. It’s an area that needs further research.

The small-scale study involved only 15 heterosexual men, but the guys proved all-too consistent in their spend-it response to sultry photos. Kuhnen says that the same link may also hold true for women, only they couldn’t test it because it’s too difficult to find an erotic image that would appeal to many different heterosexual women.

This isn’t the first time that Knutson and Kuhnen have comeup with disturbing news about our brains’ irrational economic habits. In 2006, they reported how the buzz that City share-traders get from share deals is akin to the pleasures of orgasm and the high from cocaine. They found that share-dealing lights up the same part of the brain as sex or Class A drugs. But they also found a downside. Such brain activity can and often does override the frontal cortex — the seat of reason. Thus, the share-dealers’ global trading decisions can be phenomenally illogical.

And now it looks as if they are going to get their comeuppance.

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