How do people choose what to eat? Food preferences are shaped by a variety of biological and social factors, including consumers' personalities.
Studies conducted in Germany, the United States, New Zealand, and France have shown that people who are more intellectually curious and open-minded are more likely to favor less conventional diets, such as plant-based diets. This effect could not be attributed solely to their social class, income, or level of education.
Cognitive factors may also be involved, as suggested, for example, by a 2007 study of a cohort of 8,170 English people that linked the IQ of 10-year-olds to vegetarianism twenty years later.
In a recent study conducted in France, we sought to determine whether cognitive style might be a psychological factor influencing the food choices of more than 7,000 adults.
The underlying idea was that a dietary choice followed by a minority— a plant-based diet, which is intellectually and socially more demanding—would require cognitive resources to sustain it. Conversely, one might expect that in France, an omnivorous diet would require less thought, since it is essentially driven by the majority culture and is therefore adopted unconsciously. As indicated by certain surveys and field observations conducted, for example, in Canada, our dietary choices are often the result of preferences acquired unconsciously through cultural immersion from a very young age.
A British study published in 2015, which examined samples of Americans and Australians, shows that many meat eaters justify their habits by citing the “4 N’s”: eating meat is considered natural, normal, necessary, and nice. This cultural perception of meat stems from an intuitive rather than a reflective way of thinking.
Psychologist and Nobel Prize winner in economics Daniel Kahneman has popularized two modes of thinking that we use in our daily lives: the automatic mode, which is impulsive, intuitive, and engages effortlessly, and the reflective mode, which is slower and more intellectually demanding because it involves mental processes such as reasoning based on logical or mathematical rules.
Everyone switches between these two modes throughout the day, but with certain preferences. This is exactly what the cognitive reasoning test measures—a short version of which is provided here —and it differs from IQ tests.
The higher the score on this test, the more capable individuals are of setting aside an intuitive idea that arises spontaneously when faced with a logical problem and instead providing an analytical answer that turns out to be correct.
The most well-known question on the test is the one about the baseball and the bat: a bat and a ball cost €1.10 in total. The bat costs one euro more than the ball. How much does the ball cost? The most common answer is 10 euro cents. However, this is incorrect: if the ball costs 10 euro cents, the bat would have to cost €1.10, which would bring the total to €1.20. The correct answer is therefore 5 euro cents (a ball costing 5 euro cents plus a bat costing €1.05 does indeed total €1.10).
When you tally up the correct answers to a series of questions like this one, you get a score that provides a stable, long-term measure of one aspect of a person’s logical reasoning ability. This measure is often linked to IQ, understanding of scientific concepts, and other indicators of cognitive performance—or even susceptibility to false beliefs.
What do we know about the links between cognitive styles and diet? For now, not much, since there are virtually no studies on this topic. Among the few published studies, one conducted in South Korea found that, in the context of diet, scoring higher on the aforementioned cognitive reasoning test was associated with paying closer attention to the nutritional information listed on food products.
In an initial study conducted in France, we assessed 6,200 participants aged 18 to 90 from diverse socioeconomic backgrounds using a cognitive reasoning test. The participants also reported their dietary habits and preferences in several ways.
For example, they were asked to identify with one of the categories provided (vegetarian, omnivore, etc.) and indicate which foods they excluded from their meals. Participants were also asked to answer questions regarding their agreement with the perceptions of meat as “necessary,” “natural,” “normal,” and “delicious” (the “4 Ns” mentioned above). Finally, other sociodemographic factors were also taken into account (such as age, gender, and educational level) in order to conduct analyses while controlling for their effects.
The results showed that participants who scored low on the test—and whose cognitive style was therefore more “intuitive” than “reflective”—were more likely to believe that meat was essential to health and that eating it was normal. This was true regardless of their gender or level of education. Furthermore, they were significantly less likely to exclude meat from their diet.
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Conversely, people who identified as vegetarians scored slightly higher on the test than omnivores. In fact, more than 60% of vegetarians scored above the average for the omnivore group, indicating a greater propensity for analytical thinking among vegetarians.
A second online study conducted with a sample of 1,063 paid participants aged 18 to 78 confirmed this finding and showed that it was independent of other psychological factors such as self-esteem or the simple tendency to enjoy reasoning, also known as the need for cognition.
Our findings, based on two samples totaling nearly 7,300 participants, therefore suggest that cognitive styles are linked to our eating habits, particularly to a preference for more sustainable and healthier foods.
Of course, the link we see between analytical thinking and a preference for plant-based foods might not be observed in a country like India, where meat consumption is not the culturally dominant status which is his in France.
