People who spend an unhealthy amount of time hanging out with focus groups say it's often spooky the way that attention seems to home in on just two of the ideas on view.
When a room full of people is shown a spectrum of potential creative strategies for a brand there will be one that, when prompted, a majority say they like best; but there will be a totally different execution that, unprompted, they all want to talk about and all have strong views on.
So which one do you run? Creative teams have never had any hesitation on that score. Time was, of course, that the decision was down to the marketing director - or, apocryphally, and in less politically correct times, the chairman's wife.
These days, of course, there might just be a third way. How about letting the audience choose - not in a focus-group session but live, in their homes, at the point of delivery? Actually, this is not a new question.
J. Walter Thompson and Kellogg's were among the first to experiment with this sort of thing a decade ago when they offered cable viewers the option of choosing between a number of alternate endings to a commercial.
That relied on clunky technologies. But we've moved on since then - these days, voting (because that's essentially what we're talking about) is conducted via a choice of return paths, including the internet, conventional phone lines, and, arguably most importantly of all, SMS text messaging.
It's the sort of interactivity that's been the staple of shows such as Big Brother and Popstars the Rivals for at least the past couple of years.
But it's odd, isn't it, that these techniques have barely made an impact on the way the advertising community goes about its business?
That might be about to change, though. Nike and its advertising agency, Wieden & Kennedy, have just unveiled the next stage of the Stickman campaign.
It will feature commercials that showcase the talents of wannabe ball-juggling superstars and the audience will be invited to whittle the field down in classic Pop Idol talent-show style. Votes can be cast using text, e-mail or your digital remote.
Could this merely be the beginning? Are interactive techniques increasingly going to be used to shape more involved aspects of the creative strategy?
This, after all, could be the instant version of the Millward Brown research process.
Steve Henry, the creative director of HHCL Red Cell, says that engagement has always been one of the primary goals of all good creative treatments.
In the past, the agency has toyed with all sorts of ways of making the viewer less passive. For instance, quiet commercials that force you to turn the sound up; or competition details that flash across the screen so quickly you have to video them and play them back in slow motion.
But how come interactivity has become such a staple of mainstream TV programming such as Big Brother and yet the advertising industry hasn't explored it more? "It is a balancing act because in the creative process you do tend to want authorial control," Henry responds. "On the other hand, this sort of thing is exciting for everyone to have the possibility of that degree of interactivity. Ultimately, it would be counterproductive if it became too gimmicky. But people do want to exercise control whether it's something as simple as customising their mobile phones or something more fundamental such as doing all their banking online. In effect they're demanding interactivity."
In fact, you start to realise that what we currently call interactive television advertising isn't really interactive at all. It's merely a system by which you invite the advertiser to continue making his one-way pitch to you at an even more intense level.
Jon Williams, the interactive creative director of Publicis Dialog Group (which developed a commercial where viewers could select from various creative alternatives for the charity the Depaul Trust), says we could be on the verge of a revolution. There's already evidence that in your average living room, it's becoming socially unacceptable to click on the interactive icon, thus leaving the broadcast stream and going to dedicated advertiser locations. It's all right if you're on your own but ultimately selfish if others are watching.
So the emphasis may well shift to ways in which audiences can interact directly with commercial messages.
He adds: "You engage in a deeper relationship when you get people interactively. Research shows that the communication has more cognitive resonance - if consumers feel they have influence and involvement in what's on screen then the greater their feelings towards the brand will be."
Williams is comfortable with the idea of having an ad in one break with a cliffhanger ending, then asking the audience if, say, they want the guy to get the girl or lose the girl. In the next break, you see the outcome.
"It could be like the Gold Blend commercials. People were hugely involved with those. Imagine how much more involved they'd be if they could vote on it."
But Ray Howard, the integrated creative director of J. Walter Thompson, says that for that to happen, attitudes would have to change massively - in agencies especially.
He states: "Most people still look at a budget in terms of how glamorous the TV shoot is going to be. Many advertisers have been experimenting with this sort of thing and Nike could well be the catalyst to push other brands forward. It will be fantastic when we can get people glued to the next instalment of a commercial in the same way that they're glued to the next instalment of EastEnders."
Williams seconds that. "It's high time people woke up to the potential of digital and it's great that Nike are doing this. It'll effectively put a stick of ginger up the industry's backside," he says.