So you’re about to hurl yourself on to the singles scene with a personal ad. Are you planning a conventional assault, along the lines of “outgoing brunette with GSOH seeks genuine guy”? Or do you intend to march in with all guns blazing: “Rich King Arthur hunting fit Guinevere for Round Table frolics”?

Actually, your choice of words may not matter as much as you think. And it probably doesn’t matter as much as the magic 70:30 rule. If your ad doesn’t conform to it – with 70 per cent of the ad describing you, and 30 per cent describing your ideal soul-mate – then your doormat is unlikely to be crushed under the weight of replies. Too much about yourself and you risk looking royally self-centred; too little and Guinevere will think that you’re shifty.

This enlightening discovery was made by Richard Wiseman, Professor for the Public Understanding of Psychology at Hertford-shire University. He persuaded 40 men and 40 women to write 25-word personal ads – then asked another set of volunteers to circle the ones that appealed.

The most popular ads were not necessarily the wittiest, the most sincere or the sleaziest. Professor Wiseman says: “Some ads didn’t get circled at all, while others were surprisingly successful. But it wasn’t immediately clear why the top ads did so well.

“When I was looking through them, though, I noticed that some people were completely self-centred, talking only about the traits they had. I read other ads and thought, ‘I don’t know anything about you – I only know what you’re looking for’. This factor – how much the ad focused on ‘self’ and ‘other’ – seemed to be a major variable.”

It led Wiseman to a hunch – that there may be a “golden ratio” for the perfect personal ad, in which a certain proportion of information is devoted to the writer and the rest to potential suitors.

Wiseman’s team rated each ad according to how many words were used to describe the writer and how many to describe potential respondents, and plotted these against the number of replies that each ad attracted. As he reveals in his new book Quirkology: The Curious Science of Everyday Lives, the graph peaked at the 70:30 ratio. The closer an ad conformed to this proportion, the more replies it elicited.

Could there have been something qualitatively better, such as the choice of words, about those ads? Might the 70:30 rule be a red herring? “The answer is we don’t know,” Wiseman says. “But I doubt it because we got a nice curve that peaks at 70:30.” Wiseman would like to study a larger selection of personal ads to see if the rule holds up.

If proved, it will be the kind of offbeat insight that people find irresistible. Quirkology is stuffed with them: whether your surname influences your choice of career (Wiseman offers himself as evidence for such a phenomenon); the serious, scholarly experiment to find the funniest joke in the world; how people can be made to recall things that never happened; the vain attempts to find evidence for astrology; and, of course, how to be a hot date (of which more later).

Wiseman says that the book is intended to have more than just novelty value. He wants it to inspire undergraduates to reclaim social psychology as a useful, real-world discipline; over decades, he says, it has been hidden away in the laboratory and scrubbed until sterile. Today, psychological experiments are carefully controlled but, since the orderliness of the lab does not reflect the messiness of everyday life, the results are “meaningless”.

“Psychology has become far too narrow,” insists Wiseman, 40, a trained magician who excels at experiments that capture the public imagination. “We only look at a tiny number of things and ignore the elephant in the room. For example, I know a huge number of psychologists and they know a lot about short-term memory. So they can tell you how many digits we can remember. But if you ask them about personal relationships they’ll say they don’t know. If you ask them, ‘Can you detect lying?’, they’ll say, ‘No, I don’t do that’.

“And yet, that’s real life. That’s where the real psychology is. We have dragged psychology into the laboratory and we only focus on things where we can get really good controls. For the most part, those studies don’t have any implications for people’s lives at all – they’re meaningless. I think that’s a bit sad, especially as so much of it is funded by taxpayers’ money.”

So, one of his academic excursions into the real world became a voyage through the psychology of attraction. “Psychology has been around for so many years and we still don’t know why we find one another attractive.”

The discovery of the 70:30 rule of personal ads was serendipitous (a chapter is devoted to coincidence). At last year’s Edinburgh Science Festival, Wiseman had been studying winning techniques used by speed-daters when one luckless participant said that personal ads were also failing to deliver. “I thought that sounded interesting because there’s a huge amount of psychology in personal ads. You’ve got 25 words to impress someone, and that’s your lot. So you need to choose those words carefully.”

Other scientists, such as the evolutionary biologist Robin Dunbar, had already spotted the psychological goldmine that personal ads represented, and contended that the ads amounted to little more than boiled-down versions of evolutionary theory (broody female seeks rich, intelligent male for long-term relationship; randy male seeks curvy female for noncommittal sex). Wiseman argues that this approach isn’t illuminating: “As a social psychologist I’m interested in behaviour and what elicits replies. It’s one thing to say you’re looking for a sexy woman with great eyes; but if that doesn’t bring you any women at all, let alone sexy ones with great eyes, then what’s the point?”

As well as discovering the 70:30 rule, he also unearthed a startling gender difference in the ability of men and women to pinpoint ads with mass appeal. He gave all the ads to all the volunteers, and asked them to predict which ads would prove popular. “When the guys looked at male ads, they’d instantly go, ‘that one will attract women’ and ‘that one will, too’. They were dead on, absolutely right – those ads did attract a lot of women.

“But women were blind to which ads attracted the men. So they’d say, ‘that’s a really good ad’ and no guys went for it. Or ‘this is a terrible ad’ and loads of men went for it.” He suggests that men are after quantity and women pursue quality. Somehow, this makes men better at picking out the ads that will draw a bigger response.

Conversely, a woman is more likely to dismiss ads that aren’t going to attract her particular Mr Right. The professor concludes that a woman who wants her ad to attract plenty of replies should employ a man to write it. Readers can join an online experiment to test this theory (go to www. quirkology.com).

As for speed-dating, Wiseman’s research indicates that some subjects, such as films, make dismal ice-breakers. He set up five tables for his 100 speed-daters; each table was allocated a different topic. “You walked past the film table and everyone was arguing and you realised you’d pushed those people into a very dark place,” he says, seemingly untroubled by how many epic romances may have been smothered at birth through his study techniques. “But at the travel table people talked about their holidays and seemed really energised.”

Amazingly, some speed-daters boasted a 100 per cent hit rate – which meant that everyone they met wanted their phone number. Yet they weren’t necessarily the best-looking people in the room. Their secret? Asking open-ended questions that provided scope for a lighthearted exchange.

Wiseman’s favourite was, ‘If you were a pizza topping, which one would you be?’

“It gets people to open up – it’s not a closed question. You can take it in lots of different ways and whichever way you take it, it’s going to be quite funny. But if you ask people for their favourite film, it might be something serious.” More importantly, he says, having a shared, humorous experience brings people closer and makes it more likely that they’ll want to meet again.

Does the pulling power of a shared joke explain the enduring popularity of GSOH in the personal columns? Evolutionary psychologists says that women like funny men because humour is a marker of intelligence. Do men like funny women, then? “I bet you men don’t circle ads that make them laugh,” Wiseman says. “When women offer a GSOH, it means ‘I laugh’, not ‘I’m funny’”.

So women want men who make them laugh. Men want women who’ll laugh at their jokes. Who needed a psychologist to tell them that? Quirkology: The Curious Science of Everyday Lives, by Richard Wiseman (Macmillan, £14.99)

Lonely no longer

Jacqueline Sawyer, 47, a fundraiser for the World Health Organisation, replied to an ad in the London Review of Books by Richard Gray, 50, in 2005: “Physicist with big dirt bike and swim fins seeks female pillionist to explore molecular gastronomy.” She lives in Geneva; he splits his time between there and Auckland. They married in December.

Jacqueline: I’d resigned myself to being on my own but thought I might as well give this a go. Richard’s ad was smart, but he wasn’t a total nerd because he mentioned a dirt bike. I wrote and asked him what molecular gastronomy was and we started e-mailing. I was in Switzerland, but it turned out he worked part-time in Geneva and would be there in three weeks! When we met he was how he’d seemed in e-mails: eccentric. I’d cheated because I’d looked him up on the web and found a photo. Some friends did think personal ads an odd or dangerous way to meet people, but I don’t think you know someone you meet in a bar any better.

Richard: It was the first time I’d written an ad like this, and the ironic tone was a way of distancing myself from the embarrassment of it. When Jacqueline wrote she seemed interested in what I’d written and like an interesting person herself. We got on by e-mail, then when we met it was the same. It was a bit traumatic knocking on her door for the first time. My first thought was how attractive she was, but also formidable. That hadn’t come out in her e-mails. Now it’s one of the things I really like about her.

Calling all lonely hearts

Are you a single guy looking for love and within easy reach of London? Want to take part in a times2 dating experiment? Look at the two ads below. If either ad appeals to you, send a few paragraphs about yourself to personalad@thetimes.co.uk with your selected ad number in the subject line. Please reply to only ONE of the ads. All e-mails will be read. You could be invited on a genuine date.

No1: Me? Well-travelled, fun-loving female, likes intelligent banter, good food and surprises. You? Easy-going Londoner with GSOH, interest in current affairs and enthusiasm for your job.

No2: Female, 24, attractive and articulate, fun-loving and friendly, personable and petite, into art, travel and trashy films, seeks interesting and interested, unpretentious guy for cosy chats and Italian meals.

Personality check

The Q test

What to do: Using the first finger of your dominant hand, trace the capital letter Q on your forehead.

Result: Some people draw it so that they can read it, with the tail of the Q on the right side of their forehead. Others draw the Q so that it can be read by someone facing them, with the tail on the left side.

Conclusion: This test is designed to measure whether you are “self” or “other” centred. The two types have a very different way of seeing the world, and one type is no better or worse than the other.

Type 1: Self-centred people tend to draw the letter Q so that it can be read by themselves. They tend to come across as being “the same person” in different situations, and their behaviour is guided more by their own values than by the needs of others. They pride themselves on being straight and expect others to be honest with them. They are not good at lying but are adept at detecting lies in others.

Type 2: People who are other-centred tend to draw the Q so that it can be seen by someone facing them. They tend to be concerned with how other people see them. They are happy being the centre of attention, can adapt easily to different situations and are skilled at influencing the way in which others see them. They are often good at lying but not so good at detecting lies.

Right/left-brain test

What to do: Find out whether you are a right-brain or left-brain thinker by interlocking the fingers of your hands and placing one thumb on top of the other.

Result:If you placed your right thumb on top of your left thumb, then you tend to be left-brain dominant and are more logical, verbal and analytical. If you placed your left thumb on top of your right thumb, then you tend to be right-brain dominant and excel in visual, spatial and intuitive tasks.

Conclusion:The brain works in two general modes. In one mode (called the “right-brained”) it is more intuitive, visual and creative. In the other (called “left-brained”) it is more logical, sequential and language-based. All of us work in both modes, but everyone tends towards one or the other. It is like having an artist and an accountant arguing in your head – and you keep flipping between the two.

Times recommends

• Jamie Oliver's boiling over
• Family homes for the 21st century
• What makes men commit?