If psychology has told us anything over the last 50 years, it is that we cannot trust the evidence of our senses. When we think about a product we always tend to think in terms of a single sense: How much do I like the smell of this new product, what does the colour of that one remind me of, or ‘wow’, the packaging of this brand feels distinctively different.

Our brains, however, are constantly taking in information that impinges on each of our senses (including what we see, hear, touch, taste, and smell), and using that information to form the rich and varied multi-sensory experiences that fill our lives. Thus knowing what something ‘looks’ like isn’t simply a matter of knowing what a person sees, it also (somewhat counter-intuitively) depends on what they happen to be smelling at the same time. Similarly, what a person ‘feels’ when they touch that distinctively-different new packaging has as much to do with what they hear when they touch it, as with what is going on under their fingertips.

There’s no such thing as white!

Take, for example, the perception of whiteness and softness of your sheets whey they come out of the wash. It is all about what you see and feel, right? Wrong. Many companies have been infuriated by the results of their sensory evaluation panels showing that, when they add a ‘clean’ fragrance to their new laundry detergent, their consumer panels start saying that their clothes ‘look’ noticeably cleaner, and that their whites look whiter than ever before.

What is going on? How can it be that changing a product’s fragrance changes what people see? Well, recently, cognitive psychologists and cognitive neuroscientists have started to provide some intriguing answers to these questions.

Sensory overload

It turns out that the human brain is fundamentally limited in its capacity; That is, it simply cannot cope with all of the different sights, sounds, and smells, etc., that assail the senses at any one time. Consequently, our brains use a number of heuristics, or cognitive short-cuts, in order to reduce the amount of information we have to process, and hence avoid ‘sensory overload’.

Over the last few years, researchers have started to uncover some of the key rules such as super-additivity (the idea that individually weakly effective signals, such as a faintly perceptible taste and a just discernible smell, can be combined by the brain to give rise to a flavour percept that is far stronger than the sum of its parts), sensory dominance, and multi-sensory suppression that govern how we combine the various different sensory cues and triggers present in a product, package, or environment. Much of the current excitement in the field of sensory design revolves around how a better understanding of the rules of multi-sensory integration can be used to inform product design, innovation, and evaluation.

As an experimental psychologist, I help companies by designing the experimental paradigms that demonstrate/quantify how these neuroscience principles can be used to innovate. My work also involved helping to develop tests that can deliver rapid answers to questions such as, which of these new fragrances will make a consumer’s clothes feel softest after the wash?

For example, research published by my group here in Oxford has shown that adding the appropriate fragrance to a laundry detergent will make your clothes feel as much as 5% softer. Similarly, food and drink can be made to taste 12% sweeter simply by getting the colour right (i.e., by using the sensory dominance exerted by people’s eyes over their perception of flavour), the colours associated in nature with the ripening of fruits tend to be particularly effective here.

Meanwhile, the super-additivity rule is currently being used by a number of companies to make flavours taste as much as 30% more intense while simultaneously cutting the cost of the raw ingredients.

Multi-sensory conflict

While the benefits of getting the overall multi-sensory product experience (or Gestalt) right can be dramatic, the costs associated with getting the multi-sensory components of a brand’s image wrong, or even simply neglecting one particular kind of sensory impression, can have disastrous consequences.

Just think of a beautiful meal: No matter how enticing the food smells, no matter how beautiful it looks, if it happens to be served at the wrong temperature (e.g. cold when it should have been hot) the whole experience will be ruined. As this example shows, one needs to consider all of the senses when designing a product/experience that people will enjoy.

It was the conflict between the various individual sensory cues that led to the spectacular failure of clear Tab released by Coca-Cola some years ago. Given that customers expect a drink that tastes like cola to have a very dark colour, trying to sell a cola that is as clear as lemonade is bound to confound a consumer’s expectations and hence most likely result in product failure.

Is it any wonder then that more and more companies are now all starting to use these neuroscience insights in order to design new products and packaging that can more effectively stimulate the senses of their consumers? Companies such as Nestlé, Unilever, Procter & Gamble, ICI, Firmenich, and Baiersdorf are all jumping onto the multi-sensory bandwagon.

Products and packaging

While many sensory evaluation panels have traditionally tended to evaluate products in the absence of their packaging, research is now starting to show that you cannot evaluate them both in isolation. The packaging can, and often does, have a dramatic effect on people’s perception of the product within. Consequently, changing the colour of the can will change a consumer’s perception of what’s inside, no matter whether the product is a soft drink or a deodorant spray.

Even 7-Up tastes a lot more lemony/limey to people when more yellow is added to the colour on the can. Similarly, adding a picture to the packaging can also impact significantly on people’s product perception: Foods can be made to taste hotter simply by putting a picture of a chilli pepper on the packaging.

Multi-sensory marketing

Sensory marketers have also started to emphasise the multi-sensory appeal of their products and services. Open any magazine, or turn on the TV and one cannot help but see marketers attempting to appeal to many, if not all, of their potential customers’ senses. Adverts for ‘new thicker’ Fairy washing-up liquid encourage you to ‘indulge your senses’, while those for various perfumes talk of ‘seducing’, ‘surprising’, ‘intoxicating’ and even ‘indulging’ your senses. The strap-line for one perfume even suggested that ‘I sense therefore I am’.

It would appear that any class of product can be sold on the basis of its multi-sensory appeal. Adverts for Lexus cars promise to cater to all six of your senses, while Unilever released five new Magnum ice creams, each one targeted at a different sense.

Tourist boards have also started to promote various travel destinations on the basis of their multi-sensory appeal: ‘Come to your senses in Helsinki’, for example. Meanwhile, the Greek tourist board promises that all of your senses will be stimulated if you choose to holiday there. Adverts for holidays in Scotland promise that you will not only ‘see it’, but also ‘hear it’, feel it’ and even ‘smell it’. In fact, one chain of British travel agents has even started releasing the scent of coconut oil into its high street branches, presumably hoping to conjure up memories of exotic foreign holiday by stimulating its customers’ noses.

From intuition to insight

We are now at a particularly exciting point in the development of the field of sensory (or multi-sensory) design. Traditional approaches, those based primarily on intuition, trial-and-error, and sensory consumer panels, are increasingly starting to be replaced by the novel approaches to product design and development based on the more complete understanding of the mind of the consumer, as increasingly being revealed by neuroscience.

One might ask, therefore, whether the latest insights from brain science spell the end for traditional consumer sensory evaluation panels. Well, there is certainly a palpable tension in many companies now between the more traditional approaches to product development and evaluation and those novel techniques that have recently started to emerge from psychology and neuroscience.

However, while the full potential of these new areas, such as neuromarketing, neurobranding, and neuroergonomics, etc., has yet to be seen, I would nevertheless argue that the most profitable approach for companies would be to actually try and integrate the strengths of these two very different approaches.

For, when thinking about multi-sensory design, it is important to start by considering which product or packaging features a consumer notices and/or is conscious of. What are the sensory attributes that make a product stand out from the rest in the consumer’s mind. Sensory evaluation panels are well placed to provide answers to this kind of question.

However, as a cognitive neuroscientist interested in multi-sensory design, I would then take this information, that what matters is, say, the ‘feel’ of a product’s packaging, and set about trying to change it — not by changing what the consumer feels, but instead by altering the sound that the packaging makes when they touch (based on the underlying neuroscience principles of multi-sensory perception).

And, given the increasing pace of new developments and understandings emerging from neuroscience research, there can be little doubt but that in the years to come we are going to see an increasingly-rapid shift in sensory design — a shift from intuition to insight through the better understanding of the cognitive neuroscience, or mind, of the multi-sensory consumer