Research concludes that erotic stimuli can make men more prone to taking risks
By Jasper Hamill

Ad-men have always known that flogging products to men takes little more than a tiny bikini and acres of naked flesh - now scientists have found out why.

Psychologists have discovered that heterosexual men are more likely to take risks if exposed to erotic imagery.

In a study, Brian Knutson, assistant professor of psychology and neuroscience at Stanford University, gave a group of men $10 each and made them play a game where they could gamble either a dollar or a dime.

Before they chose to gamble, the participants were exposed to one of three images. An erotic one was generally used to stimulate a positive response; images of snakes and spiders were used to encourage a negative response, while a neutral response was elicited by office equipment. Subjects had first been tested so that if a man was to find office supplies more positive than an erotic scene, they could be swapped and the images personalised.

They found that the men exposed to positive (generally sexual) imagery were more likely to bet a dollar. The negative imagery made them more likely to make the smaller bet and the neutral one meant they could go either way.

It was the first test to prove that emotional stimuli can influence risk taking. A reaction takes place in a part of the brain called the nucleus accumbens which is thought to responsible for mechanisms of reward, laughter, pleasure, addiction and fear.

Knutson said: "Most economic theories say that if there is extra information that is unrelated to the expected value of a gamble, it shouldn't influence your ability to take that gamble. If you are in a casino and you see a beautiful woman at a roulette wheel, you shouldn't be more likely to go and play at that roulette wheel, because that woman is not telling you anything about your likelihood of winning. Yet it appears from our experiment that there is an influence."

The psychologist was unsure whether the findings could have implications for advertisers or sales people, as the exposure to the images was only fleeting and the bet made immediately afterwards.

He also suggested that a similar effect could be provoked in women, but they might need a different stimulus, such as a baby's face, because they may lack a man's visceral reaction to erotic images.

He added: "Those images are very compelling to some men. You can tell by their behaviour. It doesn't make sense from a functional standpoint because it's an image, she's not a real woman, she's not looking at you and she doesn't care about you. Yet these are quite salient and compelling images to some people."

The results made perfect sense, said Cynthia McVey, a psychologist at Caledonian University, because erotic imagery caused men to become "excited and aroused" and less likely to consider the ramifications of risk.

She said: "A man may enter fantasy mode, where he thinks I wouldn't mind taking her out for dinner and all the rest of it', which is positive and makes you feel that only good things might happen to you. If you then encountered a risk-taking opportunity when you're feeling that emotion, then it might make you take that extra risk."

McVey described an experiment during which men endured having their hand dunked in ice water. The more beautiful the assistant, the longer a man would hold his hand in the ice.

However, she said this reaction did not necessarily mean men were idiots who would do anything for a pretty face.

"If you put a nice girl beside a car, then there might be the odd person, a very unusual person, who would now think I'll get the car and then I'll get a beautiful woman', but I think we're a bit beyond that now," she said.

Advertisers know the power of naked flesh; the adage that sex sells is so over-rehearsed that it's a cliché. Yet over the past 10 years, regulation has stopped the use of over-raunchy imagery, said Ian McAteer, managing director of Edinburgh-based advertising company The Union. The only adverts that use explicitly sexual imagery tended, ironically, to be adverts directed at women, for instance for underwear or beauty products.

He said: "The use of overstimulation is very proscribed in advertising these days. The days of the hidden persuaders and subliminal messages and all that kind of stuff are long gone. What this experiment says to me is that you affect people's judgement if you stimulate them sexually. But isn't that obvious?"