Great expectations

We seldom eat without bringing to the table a set of expectations about the flavours we are about to experience or the pleasure that the food will bring. Even in modern temples of molecular gastronomy, where surprise is a menu staple, we mostly expect the unexpected. One way of studying the effects of expectations on the eating experience is to manipulate what information is available to the diner and then see how the provision of information influences their evaluation of food.

The results of such studies are really not surprising. We respond to information about brands, ingredients, taste properties, popularity and so on in a way that is consistent with our valuation of that information. So, told that a chocolate is made by
Lindt rather than Hershey is likely to lead us to appreciate the chocolate even more than in the absence of such labeling.

The dining context is also a source of information, as any regular restaurant goer will appreciate. Depending on your taste in environments, a loud, crowded, bustling room can either add to the enjoyment or ruin your meal. A few years ago, it was demonstrated that the same meal was rated much more highly depending on whether it was in the context of a restaurant or a cafeteria [
1]. Adding a theme to a restaurant via decoration or music, while obvious, nevertheless adds to the enjoyment of food, as long as the theme and the food are congruent with one another.

Manipulations of expectations can also lead us to change the way we respond to the sensory qualities of a food. Told, for example, that a yoghurt is full fat rather than low fat, we are more likely to rate it as creamier and smoother. This effect is a problem for getting across health messages. Low fat, low salt, low sugar can easily translate in the consumer mind to unpalatably low flavour. As a result, the food industry has become smarter in their labeling. One approach has been to consistently, and optimistically, emphasize a product’s “Great taste” along with nutrition (“99% fat-free”) information. Alternatively, nutrition messages can be framed in such a way the “bad” news itself becomes more palatable. A product labeled as 4% fat is not viewed in the same way as the same product carrying a 96% fat-free label – one message is about how much fat is present, the other is about the fact that the product is mostly fat-free.

None of this should be unexpected if we consider that enjoyment of a meal whether at home or at a restaurant involves the integration of different sources of information. Some of this is sensory information from the nose, the mouth, and the gut, some is from our expectations based on prior experiences, and some is from expectations generated by where we find ourselves eating. This is shown most clearly when we receive information about food
after we have experienced it. It is generally the case that information is far less influential once we have had a chance to experience the food. In one study [2], for example, preference for a beer to which balsamic vinegar had been added was reduced by the knowledge that it contained the vinegar, but only if the taster was told this prior to tasting the beer. This suggests both that a food’s flavour is typically the most important source of information and also that tasting is the point at which we merge all the sources of information into an overall experience.

A food’s own sensory qualities – particularly its appearance and its aroma – are also potent generators of expectations. The fact that wine tasters will describe a white wine that has been artificially coloured red with flavour words consistent with red wines illustrate just how strong an influence appearance can be. A study just published reveals that this works both ways: that is, an aroma can also set up expectations for appearance [
3]. It might not seem surprising that an ambient aroma of strawberries means that we pay more attention to a picture of strawberries presented on a computer screen, as these researchers found. However, their study was conducted on a group of 7-month-old babies. Without the presence of the strawberry aroma, these infants paid just as much attention to the image of another red fruit, tomatoes, as they did to that of strawberries. This study is an excellent demonstration of just how early we begin to integrate different types of information – visual and smell – into a multisensory memory of a food. But the research showed too just how much this memory requires repeated learning. The study took place in strawberry season, when presumably the infants received exposure to the smell and appearance of strawberries. Repeating this study out of strawberry season showed that the sensory integration had yet to become permanent, as the strawberry aroma failed to influence the infant’s attention to the image of the strawberry.

Are such findings purely academic? Another very recent publication suggests that knowing the ways in which information from one sense can set up expectations for other sensory signals could have important implications for influencing how much we eat. Studying the influence of aroma on bite size [4], the researchers point out that smaller bite sizes are associated with weaker flavour, but also with more satiation. In this laboratory study, different concentrations of cream aroma were injected directly into the back of the nose via a tube while the participants received samples of custard into the mouth. The amount of custard consumed was under the direct control of the experimental participants, and so the effect of the cream aroma on amount consumed could be determined.

Their key finding was that the presence of the cream aroma at the high concentration resulted in significantly smaller bite sizes than when no additional aroma was present. Thus, it appears that the aroma and the custard were being combined to create a more intense flavour sensation. The researchers suggested two possible explanations for why this would affect consumption. One was that the amount consumed was being regulated in order to keep the flavour intensity more or less the same – that is, when overall flavour was strong, as when the aroma was added, amount consumed, or bite-size, was reduced; when overall flavour is weak, bite size is increased. Alternatively, it is possible that, as has been shown separately, the strong cream aroma made the custard seem thicker and creamier, an effect perhaps interpreted as an intake of more calories. Either way, these findings are significant because of the control that an increase in a calorie-free component – the aroma – appears to have on amount eaten. One approach to manufacturing lower calorie foods is to reduce sources of calories – sugars and fats – or to provide calorie-free substitutes. But it may be equally effective to reduce calorie intake by reducing the amount eaten. This approach also has the benefit of keeping the food that is eaten highly palatable.

  1. Meiselman, H.L., et al., Demonstrations of the influence of the eating environment on food acceptance. Appetite, 2000. 35: p. 231-237.
  2. Lee, L., S. Frederick, and D. Ariely, Try It, You’ll Like It. The Influence of Expectation, Consumption, and Revelation on Preferences for Beer. Psychol Sci, 2006. 17(12): p. 1054-1058.
  3. Wada, Y., et al., Infant visual preference for fruit enhanced by congruent in-season odor. Appetite, 2012(0).
  4. de Wijk, R.A., et al., Food aroma affects bite size. Flavour, 2012. 1(3).