Shops are using new spy techniques to monitor customers' facial expressions, heart rate and even pupil dilation while they browse the aisles.
New technology being installed by retailers in Europe and the US, and being trialed in the UK, can spot if a customer cannot find a product, read their reaction to an outfit or spot thieves in a bid to keep up with online retailers.
Technology installed by one French bookseller is able to detect shoppers' movements and facial expressions and alert staff that they may require assistance.
The anonymous French bookseller claimed its sales rose by 10 per cent after introducing the technology.
Meanwhile stores in Italy have started experimenting with mannequins fitted with intelligent cameras which can detect customers' facial reactions to outfits.
“These systems are designed to be completely invisible so shoppers do not know they are there,” said Mark Thompson, director of retail and hospitality at Zebra Technologies.
“They are mainly designed to improve people's shopping experience but now shops are discovering they can use hi-tech systems to catch shoplifters and learn more about their customers.”
Between last August and April, the French book chain used the software to scrutinise shopper movements, and detect customer emotions such as surprise, dissatisfaction, confusion and hesitation.
The technology discreetly nudged assistants on the shop floor with a message, who could then help the customers.
A Mothercare shop in the Estonian capital, Tallinn, which used emotion-detection technology from London software firm Realeyes, showed shoppers who entered smiling spent 33 per cent more cash than those who did not.
Thermal-imaging cameras can also detect heart rate and conclude whether shoppers are fascinated or fretting.
Shoppers have also been asked to don “galvanometer” gadgets - in exchange for a discount or reward - which track moisture and resistance on the skin that indicates arousal.
The technology could save retailers thousands of pounds by ditching the laborious marketing method of interviewing shoppers and focus groups.
Simon Harrop, from British consultancy Brand Sense, said there are some ethical concerns surrounding data protection.
“We know from research that 70 to 80 per cent of our purchase decisions are actually emotionally motivated, and are not rational,” said Mr Harrop.
“If you think about buying a house, it's about how we feel going into the house, or when buying a car, it might be about what the brand stands for.
"Everyday item purchase decisions are a bit more rational, but even something like toothpaste we buy because of the confidence it gives us in the way our teeth appear and how our breath smells.
“The video technology is not just about our physical proximity to a product, but also it's about our physiological response, such as our blood flow, the pupil dilation, and that all comes back to primeval stuff of why we are attracted to a mate.
”The challenge is that our responses are minute, but the technology is evolving all the time to increase fidelity.
“It could be unethical if it's related to a specific person and captures data specific to them, but if it's just observing behaviour in general, we can argue that retailers have always been doing this.”
Mr Harrop believes the cameras could extend to food industry as well as retail.
“In supermarkets, in deciding what height on the shelves to place products, you could show shoppers a virtual reality store and see how they react, and so bypass the cost of building it first," he said.
Realeyes chief executive Mikhel Jäätma admitted there was a “grey” area surrounding consent but said it was generally believed that a disclaimer sign would overcome this.
“I think everybody is pretty mindful and no one is considering doing this without telling customers,” he said. - The Telegraph