November 2009 - Memories of earlier experiences are a major factor in our decisions as to what we eat and what we don’t eat. They also play a central role as to whether or not a new product is accepted. Sensory researchers at the European Sensory Network believe that these memories are often more important than direct sensory comparisons. They have therefore placed “memory for foods” at the centre of their research.

One of the most important themes in sensory research is understanding how consumers decide.  Usually researchers proceed from the assumption that the consumers'  perceptions and preferences are central to his or her  decisions, and try to evaluate them. When a new version of a product is being market-tested, for instance, various difference tests are performed to determine whether or not the consumer is able to perceive a change in the product’s ingredients. If this is the case, the next question is whether this change could be a risk to the product’s acceptance. In such tests the subjects would then be given both products to directly compare them. Claire Sulmont-Rossé of the INRA research institute in Dijon France states that, “Such a situation rarely happens in real life. Normally consumers can only compare their impressions of the new product in relation to earlier experiences with a similar product. In every-day situations consumers base their decisions on their memories of earlier experiences with foods, and not on the basis of actual perceptions.”

True-to-life testing

To be able to experimentally test this memory for foods in a way that assures that the results reflect the behaviour in a real-life situation, it is important that the test is set up to be as true-to-life as possible. On this point there is wide agreement among sensory researchers.  To this end one must consider the particular characteristics of this special form of memory: among other things, in real life, first and foremost one is geared to recognise the changes (Have I already eaten something like this before? Is this the same thing I had before, or is it something different?). An exact identification and designation is almost never sought. Jos Mojet and Ep Köster, from the Centre for Innovative Consumer Studies (CICS) at Wageningen University and Research, The Netherlands explain that, “Under natural conditions the memory for foods is mostly formed incidentally or implicitly without the person affected having a conscious thought about his actual intake of the food. It is seldom that one really notices how something tastes – rather, one simply eats and enjoys without any particular focus.”

For these characteristics to be correctly observed and analysed, the researchers have developed experimental trial designs in which these everyday conditions are reproduced accurately. To be certain that subjects experience the food only in an incidental way, as would be the case in daily life, the subjects are first given a “learning session”, which obscures the true goal of the experiment. In the second part of the experiment, the memory test, the person is unexpectedly asked whether the test product served at that moment is identical to the product that was tasted in the first session, or whether it has specific differences.

Memory filters through personal priorities

In part, the results of such an experimental design differ significantly from the results garnered from direct discrimination tests. The memory of product characteristics will  not retain a 1:1 ratio; rather they will be “filtered” through personal priorities. Léri Morin-Audebrand from INRA, Dijon reports that, “For instance, in an experiment with a custard dessert, it was shown that the test subject had a more precise memory of the particular level of sweetness than of the intensity of the aroma or the exact consistency of the dessert.” In the memory for foods, it seems that one concentrates on “important” characteristics, and ignores characteristics that were perceived to be “unimportant”. Food memory is selective and can distort, and it creates expectations. In practice, that can reach the point that differences which are clearly detectable in direct product comparisons, fall by the wayside in “natural” comparisons with memory imprints. Another question is in what way the judging of a taste as pleasant or unpleasant influences memory. The researchers have found evidence that sensory characteristics that were disliked were remembered better than those that were liked.

The connection between the feelings of satisfaction and satiation after eating is also relevant to the study of the memory for foods, and is an interesting subject for research. The memory stores the closely interwoven perceptions of the sense of taste and the perceptions of the digestive organs. For sensory research, methods that would make it possible to determine a consumer’s satisfaction with a foodstuff regardless of his or her degree of satiation would be of special interest. Ep Köster emphasises that, “Since memory allows people to imagine eating experiences, it is possible to test the appropriateness of a particular food for a particular situation using completely imaginative methods.”

A child's play task

Another interesting characteristic of the memory for foods is its consistency across different age groups. Whereas explicit memory gradually develops as a child grows, and notably decreases with old age, it appears that the implicit memory for foods is relatively unaffected by ageing. Monica Laureati and Ella Pagliarini from the University of Milan have found that pre-school children can answer such questions as “Did you also eat this product last time?”, and “Do you find this product better, worse, or the same as last time?” as competently as young people and older grown-ups. The researchers point out that, “The results from the respective tests are comparable, which gives an interesting perspective into the eating and drinking behaviour of children.”

Source:
ESN-Workshop "Characteristics of memory for foods: Consequences for sensory and consumer science", at the 8th Pangborn Sensory Science Symposium, Florence, Italy, 27th July 2009

Contact:

Ep Köster
Wildforsterweg 4A
3881 NJ
Putten
Netherlands