A woman is drinking at a bar. She is alone; perhaps she is waiting for a friend. A man sidles up to her. He is nervous, unsure of himself. He is not a classic lothario, nor is he classically cool. He is probably alone too. “Your roots are showing,” he says.

She looks round, confused. Perhaps she has misheard. “Your roots are showing,” he says again, gesturing weakly at her hair. She furrows her brow. “Excuse me?”

The guy tries a different tack. He is sweating. “You know,” he says, “you look just like my little sister.”

You may never have come across this bizarre phenomenon before, but in various forms it is being practised as a seduction technique around the world. Negging, as it is called, is in essence a trick. The idea is to undermine a woman's confidence by making backhanded or snide remarks – give a compliment with one hand, and take away with the other. It is about control, putting the man in charge of the interaction by pushing the woman to earn his approval.

Someone appears to have given an implicit promise: verbal negativity means sexual success. Those two lines in the opening scenario are both real approaches recommended by seductionscience.com, one of a massive range of websites giving advice on this and other pick-up techniques.

Here are a few lines that women I interview have had used on them. “You look amazing. What have you done?” “If your face was as good as your legs I'd have to marry you.” “Nice eyes – even though one is bigger than the other.” “How brave of you to wear an outfit like that,” and even: “You have a great body. Are you bulimic?” (The last interviewee adds that she was, at the time, bulimic.)

A day spent browsing seductionscience.com – which is full of pleasant little tidbits like: “all women will turn into whores and gang-bang the whole football team if you can bring down her anti-slut defense” – is not a happy day. It offers more stock lines, like “I like that outfit you’ve got on, but your shoes don’t really match.” “Your nose is a little red. You’re like an Eskimo.” It explains: “Negging women is ideal for really hot girls – 8s, 9s, and 10s. For an average girl (6s, 7s), you don’t want to use value zingers. All you need to do is demonstrate social value – you don’t need to lower hers. Hers wasn’t that high to begin with.”

It seems, though, that these tactics can sometimes work. I speak to Rebecca*, who admits that she fell for negging when it was used on her in a bar. “I had been feeling quite low, as had recently ended a long-term relationship, and he came up to me and said something like 'you're a bit less hot than your friend, but it's OK, because I fancy you.' Obviously I am a smart, intelligent, confident and successful woman, so should have thrown something at him; but instead I was charmed.

“Anyway, at his house I found he had a spreadsheet of all the women he was seeing, colour coded with days and nights. Do I think he was using those techniques sociopathically, instead of natural charm? Yes. I think he was terrified of having a typical relationship, and he had set lines so he didn't have to risk actual intimacy.”

"Negging" and the pick-up artist was born on internet message-boards in the early '90s, and became a vast subculture, with varying strategies and tribes. It became a global phenomenon following the publication of a book by a music journalist, Neil Strauss. The book was called The Game, and it chronicles Strauss's headlong journey through this peculiar world just as it was starting to gain momentum, and his own metamorphosis into a pick-up master, teacher and guru.

The internet age taught the nerdy kid who was picked on at school that the world was theirs for the taking. The geek shall inherit the earth. Women, who retained an untamed sense of mystery, didn’t fit the matrix. So this community turned the opposite sex into a logical problem which could be solved. These men went online and started comparing notes and running experiments. They stole aspects of neuro-linguistic programming, evolutionary psychology, and some of the techniques of the salesman – the “close”, and so on. Then they hit “the field” looking for “targets”. They wrote field reports detailing what worked, and what didn't. From this, the early pick-up artists were born.

I put out an appeal online to look for someone who had successfully used negging and would be willing to defend it, and get an immediate response from Dan. “Yes, of course it works,” Dan tells me. “I like to think of it like currency: every insult increases the value of my compliment stock - which I then choose to spent wisely at maximum value and the most opportune moment for maximum effect to make my acquisition.”

There it is: “acquisition”. The lingua franca of scientific seduction is pretty unpleasant. Talk of “targets”, “acquisitions”, “sets” and so on put my teeth on edge. Language has power, and if every interaction with the opposite sex is coloured by a certain vernacular set – in this case the metaphors are all militaristic or hunting ones, perhaps with video games as their origin – then that is likely to colour the way the people who use it think about women at a fundamental level, even if they did not already think of them in this way.

But, there is another truth here. The description might be unpleasant, but what is being described is actually quite close to how ordinary flirtatious conversation works. “Writing this kind of stuff down as if its some kind of sensational trick just gives women a reason to get suspicious about a totally normal part of human interaction,” says a (male) commenter on the discussion thread I started. “It's nothing more than good natured teasing, that someone decided to coin as 'negging'. It's just a normal part of flirting. What's the big deal?”

How many of us have teased, or been cheeky, or been the recipient of such, without thinking? The problem I have is with the systematising, the same as explaining a joke scientifically – it kills it. Flirtation is not a war, requiring battle-plans and set-pieces, it is just a part of how humans interact with each other. The systematisation of this natural interaction, however, turns it into a manipulative deception.

There are really three levels of negging users. The first are the proper pick-up artists featured in The Game, who use neuro-linguistic and other more serious tricks, a sort of mind-control for seduction, which is creepy because it undermines female agency of choice and control – but also because it appears, at least superficially, to work. “I suppose I would like to think I am an individual,” says Rebecca, who fell for the pick-up artist, “but it turns out in emotional terms I'm depressingly predictable.”

The second are those like Dan, who sees himself as using his extant charm as a basis, and simply spicing it up with a few tricks here and there. The third and most common level consists of the people don't quite understand these theories, but are too shy to approach anyone any other way than with rote lines. Those are the ones who are making fools of themselves in bars, with clumsy attempts at negs.

The clichés are no longer “do you come here often”, or “nice ass” or “hey baby”; now, especially since the publication of The Game, negs are the new passé. Some of the creepier or more aggressive users have been on the more unpleasant websites, and have used the inherent hatred of women they found there to confirm their loneliness. It can be a downward spiral of misogynistic confirmation-bias.

Dan makes one last appeal for the defence. He admits that there are aspects of the community that have little respect for women. But, he says: “at the same time, there are decent, well-meaning guys out there who want to have meaningful relationships, and who get very sad that things keep going wrong for them, who just need a few pointers about how their behaviour is perceived – and what kinds of approaches would work better; and why.”

Perhaps the hypothetical shy, awkward guy in the bar I described at the beginning of the piece is looking for just that, and perhaps he has a better chance of finding it with this framework around him. But, I feel, it is more likely that framework will help him cement the idea of women as a different, inferior species, to be manipulated, hit with "negs", and preyed-upon.

The really odd thing is that the conclusion Strauss reaches in The Game, the holy bible of pick-up artists, is that picking up women is a lonely, empty, mechanical life. Strauss ends the book in a healthy relationship, which he is clear he arrived at despite – not because of – his tactical approach. The subculture that still worships him ignores this fact, feasting on the beginning of the book and ignoring the personal development at the end. Strauss's final line is: “it was time. . .to leave the community behind. Real life beckoned”.

*some names have been changed

Nicky Woolf tweets as @NickyWoolf