So what happened to the gender gap in the Scottish independence polls? The weekend’s seismic YouGov poll not only put the yes campaign in the lead for the first time – by 51% to 49% (excluding don’t knows) – but showed support for independence among women was up 14 points in a month to 47%. In other words, the long-running gender gap in the yes campaign – which has ranged from 9-22% – appears to have been practically eliminated. How come?

First, the more that voters engage, the more likely they are to vote yes. According to research by Edinburgh University, “Provision of information does affect [the likelihood to vote yes] mainly by reducing indecision … especially when a balanced set of arguments is presented, since the ‘change’ option is the one which carries more uncertainties compared to maintaining the status quo.”

It seems women were more disengaged at the start of the campaign. This is partly because arguments seemed technical and abstruse, partly because debating styles were aggressive and aimed at winning plaudits from the usual suspects – male supporters and commentators – and partly because the editorial line of most papers in Scotland has been pro-union, making “a balanced set of arguments” hard to find.

That’s changed dramatically over the past six months, with the nationwide emergence of grassroots campaigns, often organised by women with no party political involvement or experience in formal politics. Women for Independence has thousands of members and has organised more relaxed “women-friendly” events, at community centres near schools before pickup time, outside shopping malls and at weekend coffee mornings. There have been fewer “sages on the stage” and far more informal mass chats. I spoke at a Women for Indy afternoon event in the large, deprived, peripheral housing estate of Castlemilk, near Glasgow. The main attraction was the local woman, standup comedian and BBC Scotland soap opera star Libby McArthur. That strategy – of celebrities talking informally in their home towns – has been a big success with women. Street stalls have distributed free, in-depth analysis in publications such as the Wee Blue Book, produced by web campaigner Wings Over Scotland and a small mountain of YouTube videos and websites.

Second, as the penny dropped that women, not men, held the key to a yes vote, the focus of the wider yes movement changed to give more prominence to powerful female speakers such as the actor Elaine C Smith and Business for Scotland director Michelle Thompson. Artwork has also featured images of women, not men – the Spirit of Independence has become the iconic image of the campaign.

Third – as commentators like myself suggested some time ago – women have always been less likely to be “heart nationalists”, more likely to admit if they don’t know and more open to quiet discussion and persuasion, not heated Punch and Judy argument. In a testosterone-fuelled world of political analysis, that type of engagement was wrongly dismissed as dithering and indecision. It wasn’t.

Finally, the general vibe has changed. Female voters now sense optimism about the possibility of real change, where there was previously a sense of uncertainty and difficulty. That is partly due to a change in tone by the once ebullient Alex Salmond, who stopped shouting, opened up a wider set of issues than currency – including health, poverty, bedroom tax, austerity and Trident – and scored with female voters in the first TV leaders’ debate, despite being judged the loser by political commentators.

Salmond’s wider subject choice, combined with the new, less smug tone produced a victory among all groups in the final televised debate, and was a game-changer.

However, all of that overlooked the contribution from the deputy first minister, Nicola Sturgeon, whose calm, surgical dissection of the former Scottish secretary Michael Moore led to his replacement by the more bullish Alistair Carmichael – himself demolished by the impressive Sturgeon in a subsequent TV debate. Sturgeon’s approval ratings in Scotland have topped those of all male performers including Salmond for more than a year – in a less sexist society, she would unquestionably have been named Person of the Match.

More than all these slugging contests involving professional politicians though, the positive, creative energy generated by the wider yes movement has been its greatest achievement – even attested to by unionist commentators such as the Spectator’s Alex Massie, who said: “This vigorous political carnival … has been a revolt against politics as usual: a cry, from the heart as much as from the head, for a different way of doing things.” The recent YouGov poll supports that view – 60% of those sampled thought the yes campaign was more positive than negative, while views of the no campaign were precisely the other way around.

Relentless positivity, combined with well-constructed arguments by local, articulate, non-party-political female yes volunteers, and a less aggressive tone from yes-supporting men, has made yes a more attractive proposition.

Of course with a week to go, there is still plenty to fight for – indeed one new poll puts the no campaign back in front. But there’s a dedicated and well-organised band of female yes volunteers in every town ready to make sure the mould of Scottish politics is well and truly broken next Thursday – in more ways than one.