With Stuart Rose saying Marks and Spencer is now focusing on what the customer wants, this year's great performance indicates M&S has understood that the expectations of its customers have changed and it has responded ­accordingly.

Our research shows more than 50% of the customer experience is based on emotion, with many front-line service jobs bringing complex communication challenges that require workers to respond appropriately to the subtleties of what their customers want and expect. Over the past few years, M&S has gone through the pain of adapting to the changing expectations of its customers, working to deliver a better service and store environment.

M&S realised the need to redesign the customer experience in a noisy and increasingly commoditised marketplace where trust and reassurance is key. The transition is not complete but if M&S continues to meet customers' physical and emotional expectations it should continue to have strong results.

Both Tesco and Morrisons repor­ted outstanding half-year results - but for very different reasons. ­Beyond Philosophy, an advisory consulting organisation that focuses on building great customer experiences for its clients, has undertaken research and identified the 20 emotional triggers that drive the customer experience. Tesco's success may be characterised as being heavily centred on the triggers 'safe' and 'exploratory', while Morrisons strategy is centred more on 'safe' and 'focused'. In other words, consumers feel safe that Morrisons and Tesco will provide the experience, products and service they expect.

Interestingly, the strength of these results suggest that both Morrisons and Tesco are actually exceeding those expectations in the first half of the year.

Morrisons and Tesco both claim to offer low prices, relative to the competition, indicating that the market they compete in is commoditising. As a result, grocers must find a way of differentiating themselves. At Tesco this is based on one-stop shopping, while at Morrisons it is a more concentrated experience.

A simple but fundamental issue that arises when initiating a customer experience strategy is how to generate it. From where should you start to ensure you end up with a customer experience that produces the benefits you are looking for, and one that customers will recognise and recommend? Sainsbury's 123% rise in interim profits this week is a reflection that in part it understands this difficulty - investing in both in-store improvements and training for management and shopfloor workers to provide faster and friendlier service.

With the busy Christmas period here again and aisles filling up with shoppers hunting for mince pies and wine, Asda, Morrisons, Sainsbury's et al need to set a clear customer experience strategy founded on understanding their customers' expectations - or risk losing out to Tesco again this year. Retailers must be brave enough to look at the customer experience they are delivering - and the one they want to deliver.

As many consumers break out of their normal shopping routines during the Christmas period, supermarkets have an opportunity to pull in new customers. Grocers need to look at the customer experience as a way of differentiating themselves in order to retain these customers.

Retailers must also consider all areas in which shoppers interact with the business - the internet, direct mail, call centre, in-store. All these channels need to be considered, because problems can arise from well-intentioned variations.