When a man thinks his partner is cheating on him, chances are fifty-fifty that he's right. But if a woman suspects her nearest and dearest of being unfaithful, she's correct a whopping 85 percent of the time.
Special intuition? No, simply numbers - as compiled in "Love by Numbers," a wide-ranging and sometimes wacky look at the figures and trends behind how and who people love, drawn up by Australian statistician John Croucher as a tongue-in-cheek way, so to speak, of making sense out of romance and sex.
"Ask men what makes their blood run cold when your partner says it to you and number one in all the surveys I've seen is, 'We have to talk.' Men don't want to talk and if she does she's either going to leave him, found somebody else or found something out about him," said Croucher, a professor at Macquarie University, as an example.
"The second one was 'Who was that woman I saw you talking to?' I think for women it was 'What's for dinner?'"
Among the many tidbits in Croucher's book, the result of years of research plus a study of people's behavior in speed dating, are things as disparate as the fact that 68 percent of men think a woman's invitation to have coffee is really an invitation to have sex, or that 11 percent of respondents in the United States have ended a relationship because of a cat.
Given that some 60 to 90 percent of physical communication between humans is due to unspoken signals, a sizeable chunk of the book is devoted to how to translate that body language in the most useful way.
Guys, want to look attractive to women? Wear a red shirt and chat up another woman - or better yet, two women. But if you're a woman, men find you more appealing if you're alone.
A woman who flips her hair or crosses her legs is trying to get a man's attention, as is one who strokes a rounded object like her drinks glass. But if she puts her purse behind her this is not a good sign - the bag is an extension of herself, and she's hiding.
Though Croucher acknowledges that some of the answers, particularly those dealing with sexual partners, are subject to some adjustment, many are a useful guide to how humans think.
"It just tells us about human nature, I suppose... It's like asking a man how tall he is, he'll add on 2 to 3 cm (0.8-1.2 inches) - but if you ask a woman her weight she'll take off 3 kg (6.6 lb)," he said.
"It's a fun thing but it's also a serious thing because you can actually look at the way the rest of the world behaves and their attitudes and human nature and relationships."
One of his personal favorites? The question about whether people would marry their current partner if they knew then what they know now - which in some cases yields negative replies from up to 70 percent of women.
"They ask people do you still believe in love at first sight and do you think you married your soulmate, and only 39 percent of people think they've married their soulmate," he said.
"Twenty-one percent thought they'd married their soulmate but turned out to be wrong, and 32 percent were sure that they didn't. So fewer than 2 in 5 married their soulmate."
Oh, and to answer another one of a relationship's more treacherous questions: 52 percent of men say they would lie if asked by their partner, "Does my bum look big in this?"