Heuristics in food choice, how do we choose what to eat and how much to eat?

Heuristics in food choice, how do we choose what to eat and how much to eat?

Ian and Jill were on their lunch break from a long and busy day at work. They both worked in the same office and liked to get out of the office environment for an hour to eat their lunch. Just like on any other day Ian and Jill walked from their office down the street to the local food court. Neither Ian nor Jill were picky eaters they’d just eat whatever they felt like eating. As they got to the food court they both looked around at the large number of restaurants and cafes that they could choose from to purchase lunch. Jill looked at Ian and said “Well, where should we eat today? There are so many choices here.”

In many countries, we live in very food-rich environments. In supermarkets, we can choose from thousands of different items of food, and from this we can combine these food items into tens of thousands of different dishes, albeit with a little help from our recipe books. When we go out to eat like Ian and Jill we encounter vast numbers of dishes to choose from. Most consumers are not aware of it but on a day-to-day basis we make an estimated 200 food choices (Wansink & Sobal, 2007). Of course, we don’t like to agonise of what to eat for lunch so we like to use simple effortless strategies. The lack of any deliberation leaves us susceptible to ‘rules-of-thumb’ (mental shortcuts known as heuristics).

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So, what heuristics are involved in food choice?

When stood at the doors of the food court looking at the dozen or so restaurants ahead of us many us like to consider one attribute of food to be the most important (e.g., low in calories, inexpensive, convenient etc.). A heuristic known as the lexicographic decision rule, LEX for short, accounts for this by saying that we make our decision based on the food that satisfies an attribute the most (e.g., the food alternative with the lowest number of calories). If two foods are equal on the first attribute the second most important attribute of the food acts as the tie-breaker (e.g., convenience and inexpensive).

Academics at the Max Planck Institute in Berlin have investigated the lexicographic decision rule in food choice (Schiebehenne et al., 2007). In 2006 the researchers conducted a study at the Potsdamer Platz Arkaden, a large shopping centre in Berlin. They had students rate food along 38 different attributes (e.g., price etc.). The researchers then used the information from the students in a study were participants were shown 10 photographs of food dishes with the name of a restaurant, the price and type of food (e.g., Indian or Italian food). Participants choose a food and rated their choice on the 38 attributes. Example foods from this study include Big Mac burgers, Bockwurst with potato salad, chocolate muffins, lasagne, sushi and pizza. The results of the study found that participants did mainly consider only one attribute when making their decision about which food to eat. When tied on the single attribute with another food they simply considered the second most important attribute (is this low-calorie food as inexpensive as the second low-calorie food?). The lexicographic decision rule was able to predict the food choice that participants in this study made after considering what single attribute was of the most importance to a participant.

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Another strategy for food choice that many people use is evident in people who keep to strict diets for religious reasons or health reasons. Experienced dieters often practice rules that become habitual, for example, avoid all chocolate. When practiced frequently dietary rules become internalized and can be used as rules-of-thumb, however, this lack of conscious deliberation can leave us susceptible to other cognitive processes, even when trying to avoid sugary chocolate. The size of plates and serving utensils are just one of the things have been shown to influence how much we eat when serving our own food. People tend to serve themselves more, and eat more from larger bowls and plates than when given smaller plates, even when given the option to return for a second serving had they received a small plate (Gier et al., 2006). As for beverages, when given a tall drinking glass people pour more than when they have a short glass (Wansink & Van Ittersum, 2003).

For most of us who do not follow a particular diet and like to try different foods the lexicographic decision rule can be a great decision aid because when using this we don’t have to consider a lot different competing attributes of a food dish. In the case of Ian and Jill walking into the food court satisfying their joint desire to eat healthy the lexicographic decision rule works well to help them avoid the many fast food outlets. However, for those who are aiming to avoid chocolate (or any other single food) we should be aware of the other cognitive processes at work, after all a large plate does not mean that we all have to fill the plate completely.

Dan Edgcumbe

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