True, Helsinki is not the first place that springs to mind when studying the buying habits of British consumers.
But Ambler needed to borrow a piece of hi-tech medical kit that would allow him to see exactly what was going on inside consumers' heads as they went shopping. The device, called (take a deep breath) a Magnetoencephalograph (MEG), measures electrical activity in the brain and the European Union-funded MEG in Helsinki was the only one available.
Once installed in the MEG suite at Helsinki University, Ambler played his subjects a shopper's-eye film of various supermarket fixtures and asked them to go on a virtual shopping trip. He used the MEG to record millisecond by millisecond exactly what went on in their brains as they made their choices from the brands on offer.
It is commonplace wisdom these days that brands are primarily mental constructs and they exist not under lock and key in the office of the brand owner, nor even on the shelves of the supermarkets that sell them, but in the minds of consumers.
As a result of his experiment, Ambler can now take this argument one stage further. He is now able to suggest exactly whereabouts in the minds or brains of consumers brands might exist.
"At least part of brand equity seems to reside in a small area of the brain above and behind the right ear called the right parietal cortex," Ambler says. "It's a part of the brain that expresses plans and purpose. We know this because that is the part of the brain that lit up in all our subjects when they expressed an intention to buy. This we take as evidence of the location of brand equity."
Finding out what consumers really think about products and communications has long been a major preoccupation of the advertising and marketing industries. They have always been swift to appropriate techniques from other disciplines if it looked like they might shed light on the murky and elusive mind of the consumer.
Researchers such as Ambler have now begun to ask whether the comparatively new medical discipline of neuroscience, which studies the workings of the brain, has anything to offer marketers interested in finding out how consumers really react to their products and commercials - as opposed to how they say they react.
The technique employs traditional neuroscientific methods to determine the drivers behind consumer choice.
Researchers map brain patterns to reveal how they respond to a particular ad or product. The insight provided can be used to develop new (hopefully more effective) advertising campaigns and branding techniques.
The resulting field of study has become known as neuromarketing. It aims to address a broad range of marketing topics such as brand communications, merchandising and product development by using medical technologies to bypass conventional information gathering and study the patterns of brain activity that might reveal how a consumer is actually evaluating a product, packaging or advertisement.
An example of how neuromarketing techniques can side-step weaknesses in qualitative research is provided by the psychologist David Lewis of the research company Neuromix. He, too, has been studying shopping habits, this time by equipping volunteers with portable Electroencephalograph (EEG) helmets resembling colanders with electrodes.
He says: "I sent some young men round Bluewater shopping centre and asked them about their experiences when they returned. There was much banter about Ann Summers and the respondents claimed it was their favourite shop.
"However, when we checked their accounts against the EEG data, we discovered that really they weren't that interested in Ann Summers at all. The shop that really lit up their brains was the Nike store next door, where they were deeply excited by some new blue trainers. They clearly felt that they were expected to respond to sex although they were much more interested in shoes."
Three main technologies are employed in neuromarketing. The best known is functional Magnetic Resonance Imaging (fMRI), a technique first used in 1992, which measures blood flow to different parts of the brain and provides detailed moving images of changing patterns of brain activity.
Then there are MEGs, widely used in psychiatry and the development of drugs, which measure electrical activity within the brain. Finally, there are EEG, which measure electrical activity taking place on the surface of the brain.
There has been much hype around the subject during the past year or so, with articles particularly in the US press describing the new field as "Orwellian" and suggesting that any day now we will all be turned into automata as marketers learn to "press the buy button in our heads".
"If only", would be the response of many in the industry. Predictably, the reality is less exciting. Even its strongest advocates admit that neuromarketing is still scarcely beyond the embryonic stage when it comes to insight and commercial application. Lewis likens the current position to the Wright brothers at Kitty Hawk. "We know our machine flies.
We believe it has enormous potential to transform marketing once companies have become more familiar with and trusting of the concept. But it is still at a very crude stage of development."
"We are at the primary rather than the applied stage of research with these techniques. We are still establishing whether this technology provides valid information and what sort of questions we can reasonably ask of it," Ambler agrees. He is in the process of looking for funding for further studies.
If it is early days for primary research in neuromarketing, applied neuromarketing research is scarcely a twinkle in a handful of entrepreneurial eyes. Research for this article turned up just two UK companies capable of commercial neuromarketing techniques, another two in the US, as well as one each in Germany and Denmark.
They have had, at most, a handful of clients between them. Coca-Cola is said to have looked at the use of MRIs in the US. DaimlerChrysler has funded some exploratory research in Germany and, a couple of years ago, Ford Europe conducted a pilot study of the use of EEGs to assess advertising in the UK.
The field is small and the number of people with experience of it, but no vested commercial interest, is even smaller. But, like almost everyone who has looked at the subject, Pat Farrell, the global manager for consumer insight at Ford, is excited by its potential to provide deep and accurate consumer insight. Ford recently tested the use of EEGs in assessing commercials. "There is no refuting what your brain is doing. Our test showed us what part of the stimulus had been remembered, at what points people were emotionally involved and whether they were really paying attention at all."
He is reluctant to divulge much detail - it gives too much commercial advantage, he says. But he describes some of the general insights provided by the technique. "We learned, for instance, that very often the endframe kills communication. Loss of engagement occurs when the action is resolved.
So the learning was 'don't resolve the plot before you have got your key message across'. We found that men engage well with car ads but women only switch on when people are involved. We also learnt that music is much more important than we thought. It seems to switch on memory and deepens emotional response."
Farrell's measured conclusion is that: "Our neuromarketing experiments showed potential to be significantly reliable." Ambler is even more positive about the potential for neuromarketing. "In time, this science is going to develop. When it does I can't overestimate how big an impact this is going to have - in time," he says.
A less objective commentator, Dr Clint Kilts, a professor in the department of psychiatry and behavioural sciences at Emory University and a co-founder of the Brighthouse Institute strategic marketing consultancy in Atlanta, Georgia, predicts the application will become common. "We will eventually see these techniques becoming part of the decision-making process up and down companies, and many large businesses will have their own neuroscience divisions."
However, even the most ardent supporters concede that it is likely to be decades before it becomes widespread - if only because it is going to take that long to train up enough people with sufficient high-level skills in both marketing and neuroscience.
In the meantime, despite its clear potential, neuromarketing faces resistance (or at least wariness) on three very different fronts. The first are what you might call practical objectors. These tend to be the people who actually might have to integrate neuromarketing insights into their work.
Farrell, for instance, is concerned that the very act of administering neuromarketing techniques will alter outcomes. "Sitting in a metal tube with wires attached to your head isn't exactly the same as watching TV at home, is it?" he reasons. Also, the fact that much of the technology is immobile and rare means that respondents, such as Ambler's 18 volunteers, have to travel, often some distance, to be interrogated.
There is also the question of price. It costs between £500 and £1,000 to put just one respondent in an MRI or MEG machine. A recent MRI study by the Brighthouse Institute cost $250,000, putting such research beyond the means of most marketers.
On the other hand, EEG technology is far cheaper (not much more expensive than group discussions) and more portable but, according to some, it sacrifices depth and quality of information, which is the whole point of studying the brain.
Then there are what might be called philosophical objections. Russ Lidstone, the head of planning at Lowe, has rebuffed approaches from neuromarketing companies recently, largely on the grounds that the analysis provided was too mechanical. "It was all interesting but I worry about the black-box technology. The idea of analysing ads second by second seems dubious. It's the same argument used against much pre-testing: if you analysed Shakespeare that way you would edit out most of the plot."
A more emotional case is made by those with ethical concerns over where neuromarketing might lead. Neuromarketing appears so invasive and powerful that it has raised the spectre of what some consumer groups in the US are calling mind-control; it exacerbates the worst excesses of consumerism, they argue.
Gary Ruskin, the head of the US-based consumer group Consumer Alert, believes neurological marketing is unethical because it will amplify what he sees as marketing-related diseases such as obesity and anorexia. "It is hard to think of a single benefit that could result from teaching corporate marketers how to press a 'buy button' in the minds of individual Americans," he insists. "Is there really a person in America who is insufficiently impelled to eat more Pepperidge Farm cookies or drink more Coke?"
Almost certainly not. But the California-based Center for Cognitive Liberty & Ethics (CCLE), a research and policy charity that describes itself as "devoted to protecting freedom of thought", concludes that neuromarketing really doesn't represent a significant threat.
"There is no doubt that we as consumers are being programmed all day long. Look at muzak, supermarket lay- outs, advertising. But neuromarketing seems to be simply a more advanced version of what we already have got. It is just a difference of degree, not kind," Richard Glen Boire, the director of CCLE, says.
Gemma Calvert, a co-founder of Neurosense, which is pioneering the use of MRI technology in UK market research, seconds that. "This technology simply helps marketers do things they already do, but more effectively. There is not even the possibility that we will be able to control people's thoughts. The main benefit isn't so much new learning as new certainty. It confirms much that we already think we know but we are not sure we know."
Calvert is currently cogitating on the issue of why low-fat crisps don't taste as good as normal crisps. She is trying to find the key cues - visual, taste and textural - that will allow manufacturers to make our experience of low-fat crisps as close as possible to full-fat versions.
That is a comparatively benevolent application. But it is not difficult to see the potential for using such insights in a less beneficial way - especially once the field is more advanced. As Lewis puts it: "In 100 years' time, the techniques and technology being employed will bear as much relation to what we are using and doing today as the Wright brothers' piano-wire biplanes do to a 747."
It seems neuromarketing is such a sharp new tool with such potential for good or ill, that advertisers will have to be very careful they don't cut themselves.