50 years in search of the consumers’ true motivations

The European Sensory Network is celebrating the 75th birthday of its co-founder and scientific advisor Egon P. Köster, sensory expert and Professor emeritus of Experimental Psychology.



People only eat what tastes good to them and only buy what they like. Yet the question of what is accepted by whom is not easy to answer. Consumer sensory research attempts to get to the bottom of this question and to discover which product attributes are decisive and which preferences influence the consumers' purchasing decisions. Egon Peter Köster, nestor of applied consumer sensory research in Europe, is Professor Emeritus of Experimental Psychology, and as such has a deep understanding concerning the twisted paths of human decision-making.

Ask coffee drinkers in Germany why they like their coffee, and 80% will most probably reply, “Because it is mild”. However, almost no one can explain what he or she means by this expression. Also, in direct taste  comparison tests in which a variety of coffee sorts are tested; mild sorts are not clearly preferred. So are the consumers lying when asked to describe their preferences? “Yes,” says Prof. Egon P. Köster, “but not out of maliciousness.” The problem is that they have never consciously analysed what they experience while eating and drinking. Thus they have great difficulty when they all at once try to articulate that experience. Köster believes that, “Essentially, the normal consumer doesn’t have the slightest idea why something does or doesn’t taste good. The word “mild” comes up because the word appears in connection with coffee in almost every coffee advertisement.”


Direct questions are misleading

“In consumer sensory research, you don’t get very far asking direct questions; the answers you get will most probably be misleading,” discloses the psychologist. For over 50 years Prof. Köster has been researching the real wishes of the consumer and the reasons behind their behaviour, which is often hard to predict. He is convinced that, “If you really want to find out what influences the consumer, whose choices are greatly determined by unconscious processes, you need to do it indirectly.”

This was shown e.g. in two connected milk experiments that were conducted in Holland. In the first test, milk with various levels of fat content was placed before a group of consumers who were then asked to indicate the one which they usually drank (1.4% fat content); they failed in the task. However, in the run-up to a second experiment researchers told the participants that only a portion of the milk samples were from Holland and that the rest were imported at cheaper prices and sold in Holland at the same price as the domestic brands. Now the majority of those taking the test were suddenly able to reliably identify the milk that they usually drank.


The stomach is more trustworthy than the head

Köster’s interpretation of the milk experiment was that, “Obviously the test persons show a more spontaneous ”gut” reaction than an “analytical” one when confronted with a story that raises emotions. It angered the test subjects that out of pure greed someone would replace a product that consumers like with a substitute; this made the subjects more critical and inhibited the rational control of their spontaneous feelings.” Interestingly, in such a state, which is mainly controlled by the subconscious, the ability to detect subtle differences increases more – as was the case in the milk test – than by tackling the problem analytically. 

Consumers often choose subconsciously and intuitively in everyday situations. In such situations they are very sensitive to changes in what they are used to. When something does not fit to the expectations stored in the subconscious, people will generally react quite negatively. Köster finds, that “from an evolutionary standpoint this makes sense. In the history of humankind, when the so called “near senses” - smell and taste - perceived a change, this meant a potential danger of poisoning. This could be best prevented by spitting out whatever had an unfamiliar taste and thererfore did not meet expectations formed by former experiences.” Whether or not a product will be accepted does not depend on its sensory properties alone; it depends at least as much on the consumers’ expectations, which are for the most part unconscious.


The strength of imagination

Köster states that modern consumer sensory research test methods should take this relationship between sensory properties and consumer expectations into consideration. “It is important to not only ask test participants if they like or dislike the tested product, but also take into account the day to day situations in which it is consumed. What might taste good in a laboratory setting doesn’t necessarily taste good in a daily real-life setting. This problem can be solved e.g. through verbal or pictorial sketches that help the test persons to imagine themselves in the real life situations in question. As Köster and his co-workers were able to show, judgements that are collected by such means are more reliable than data collected without this kind of support.


The best is not always the first choice

As E.P. Köster sees it, consumer research comes up short when it takes note of the test ratings alone and brings the product to market readiness solely because it has the highest test results. “We often observed that such products were at first successful but then suddenly flopped. One  reason for this is that the consumers’ preferences are continuously changing. Among other things people are always looking for new experiences to allay their boredom by bringing more variety into their lives. The best long term success is achieved with products that are rated positively on first consumption, but that are also complex and multi-layered. This allows the consumer to continually discover new aspects. “Such products can satisfy the basic human need for excitement and stimulation.

ESN pays tribute to the Organising Committee of the 2nd European Conference on Sensory Consumer Research of Food and Beverages in the Hague, entitled "A Sense of Diversity", who took the initiative and organised a special session of their congress devoted to the work of E.P.Köster


Expert-Interview with E.P. Köster


Download press release (PDF)

in English (link)

in German (link)

For additional information or digital picture files please contact the ESN press office. (E-mail)

This text is also available on openpr.de


Photo: zhong/aumkii