When babies identify meaningful cultural differences

Note: This piece first appeared in the New York Times on August 19, 2016 as “Babies Watching People Eat”.

You may not be surprised to learn that food preference is a social matter. What we choose to eat depends on more than just what tastes good or is healthful. People in different cultures eat different things, and within a culture, what you eat can signal something about who you are.

More surprising is that the sociality of food selection, it turns out, runs deep in human nature. In research published this month in the Proceedings of the National Academy of Sciences, my colleagues and I showed that even 1-year-old babies understand that people’s food preferences depend on their social or cultural group.

Interestingly, we found that babies’ thinking about food preferences isn’t really about food per se. It’s more about the people eating foods, and the relationship between food choice and social groups.

While it’s hard to know what babies think before they can talk, developmental psychologists have long capitalized on the fact that babies’ visual gaze is guided by their interest. Babies tend to look longer at something that is novel or surprising. Do something bizarre the next time you meet a baby, and you’ll notice her looking intently.

Using this method, the psychologists Zoe Liberman, Amanda Woodward, Kathleen Sullivan and I conducted a series of studies. Led by Professor Liberman, we brought more than 200 1-year-olds (and their parents) into a developmental psychology lab, and showed them videos of people visibly expressing like or dislike of foods.

For instance, one group of babies saw a video of a person who ate a food and expressed that she loved it. Next they saw a video of a second person who tried the same food and also loved it. This second event was not terribly surprising to the babies: The two people agreed, after all. Accordingly, the babies did not look for very long at this second video; it was what they expected.

But when the babies saw the second person do something less expected — when this second person instead hated this same food that the first person loved — the babies looked much longer.

In this way, we were able to gauge infants’ patterns of generalization from one person to another. If babies see someone like a food, do they think that other people will like that food, too? And if so, do they think that all people will like the same foods, or just some people?


We found some surprising patterns. If the two people featured acted as if they were friends, or if they spoke the same language, babies expected that the people would prefer the same foods. But if the two people acted as if they were enemies, or if they spoke two different languages, babies expected that they would prefer two different foods.

It was as if cultural lines were being drawn right in the laboratory. And in the babies’ minds there seemed to be something special about the link between culture and food: When the babies saw people liking and disliking inedible objects, we didn’t observe the same patterns of results.

One thing you may be wondering — and we were, too — is whether this is all about the foods people like. Whether you like grits or kale may depend on cultural identity. But there are some things that are disgusting to all humans, regardless of culture. Do babies intuitively know this?

Indeed, they seem to. When the babies in our studies saw a person act disgusted from eating a food, they expected that a second person would also be disgusted by the same food — regardless of whether or not the two people were in the same social group.

We also discovered something interesting about what babies identify as meaningful cultural differences. Babies from monolingual English-speaking homes saw language as a marker of different cultures; as noted above, if two people spoke two different languages, babies expected that they would prefer two different foods.

In contrast, babies from bilingual homes assumed that even two people who spoke different languages would like to eat the same things. Thus babies have the potential to learn different things about the foods and people around them, depending on their social environments.

Parents of young children may want to take note of our findings. Infants are not just learning to eat the foods they are given; they are also learning by watching adults eat, and figuring out who eats what foods with whom. By introducing babies to social contexts in which adults make healthful food choices, parents may help children learn the cultural norms of healthful eating themselves.

Katherine Kinzler is an associate professor of psychology and human development at Cornell University, and scholar with the project Virtue, Happiness, & the Meaning of Life.

Virtue Talk podcast: “Early learning about food is really learning about people” – Katherine Kinzler

virtuetalklogorsClick the link below to hear our scholar and Associate Professor of Psychology and Human Development at Cornell University Katherine Kinzler discuss her work in child food preferences (with collaborators Zoe Liberman, University of California, Santa Barbara; and at the University of Chicago, Samantha Fan, Amanda Woodward, Boaz Keysar); and how working with scholars in our project across the fields of psychology, philosophy, and theology has impacted her approach to thinking about her research.

Next week on The Virtue Blog, we’ll post related writing by Kinzler.

Katherine Kinzler | Virtue Talk

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Katherine Kinzler (left) with Candace Vogler at our June 2016 working group meeting.

Katherine Kinzler is Associate Professor of Psychology and Associate Professor of Human Development at Cornell University and Scholar with the project Virtue, Happiness, & the Meaning of Life. Read more here.


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Food Preferences, Temperance, and Virtue

Baby eating dragon fruit
Adobe stock photo.

The concept of habit plays a central role in Thomas Aquinas’ moral theory, and in his analytic psychology more generally. He identifies habits as one of the fundamental principles of human action, together with the capacities of intellect, passions, and will – appropriately so, because habits are nothing other than stable dispositions of these capacities, which enable them to operate in coherent, appropriate ways. Habits are subject to moral evaluation, just as actions are, and the habits of the passions and the will are always either virtues or vices, just as human actions are always morally good or evil. Even more fundamentally, habits of some kind are necessary to the functioning of both the appetites and the intellect. Without some kind of internal development and formation, the appetites and the rational powers of the human creature cannot function at all, or can only operate in rudimentary and ineffective ways. By implication, human action as we know it, whether from our experience as agents or by observation of others, is almost always shaped by habits of some kind, formed out of natural (or supernatural) principles of operation through processes of training and development. Human existence and action is ultimately grounded in natural principles, but the innate principles of human action do not enter directly into our ordinary experiences – rather, we act and interact with one another through the structures set up by the stable dispositions of our virtues, vices, and other habits.
These are claims about the origins and structuring principles of human action, and as such, they invite comparison with other kinds of claims about human psychology, including those set forth by contemporary experimental psychology. A comparison of this kind might seem to be ruled out by the radical differences in assumptions and methodology that divide Aquinas from contemporary scientists of any kind. Yet when we compare what Aquinas says about the habits, we find unexpected resonances with recent work on the formation of stable dispositions, especially those relating to such fundamental matters as food preferences. We need to be careful not to overstate the extent and significance of these resonances. However, it would seem that at the very least, Aquinas and contemporary psychologists share points of reference that enable us to compare them in fruitful ways. To put it crudely, we can assume that they are talking about the same things, more or less, namely, human activities and experiences, together with whatever principles or structures account for these.
I want to defend and develop this way of approaching Aquinas’ psychology by comparing what he says about the formation and necessity of habit with recent work on the formation of food preferences in infants. This research lends support to Aquinas’ view that even the most fundamental human capacities for desire and aversion need some kind of rational formation and structuring in order to function properly. Indeed, Aquinas’ analytical psychology and contemporary experimental psychology seem to converge, and for a Thomist, this convergence suggests that research in this area might tend to confirm—or at least shed light on—Aquinas’ account of a virtue such as temperance, as it pertains to the pleasures of food and drink. When we turn back to relevant studies, however, it would seem that they challenge Aquinas’ account of temperance, insofar as he defines this virtue by reference to the individual’s bodily needs. On further reflection, contemporary work on food preferences is not inconsistent with Aquinas’ account of temperance, but it does suggest that a Thomistic account of the virtue of temperance needs to be expanded and developed in certain ways, if we are to do full justice to the complexities of developmental formation.

Adobe stock photo.

Habits are commonly associated with stereotyped, repetitive behaviors that often fall outside the range of one’s conscious awareness and may even be experienced as somehow contrary to one’s desires. A habit in the Thomistic sense more nearly resembles a skill, such as touch typing, than a habit like pulling one’s beard – indeed, the skill of touch typing is a habit in Aquinas’ sense, whereas beard-pulling is not. Habits understood in this way are clearly more interesting and important than the kind of habits that we only notice when we want to break them. But we have not yet taken full account of just how important habits are, on Aquinas’ view. He claims that habits of some kind are necessary for the proper functioning of the rational creature. Human capacities for perception, understanding, and desire are naturally indeterminate, and stand in need of some level of development in order to function at all.
Contemporary developmental psychology offers at least one example of a kind of system that would appear at first glance to function in much the same way as do the habits, as Aquinas understands them: “[E]ach of a multitude of core knowledge systems emerges early in development, serves to identify the entities in its domain by analysing their distinctive characteristics, and supports the acquisition of further knowledge about those entities by focusing on the critical features that distinguish different members of the domain (Shutts et al).” A system of core knowledge would thus seem to provide the same kinds of rational structures, and thus to facilitate appropriate functioning, in the same way that habits do. Systems of core knowledge would not be equivalent to habits as Aquinas understands them, but on the contrary, they would provide evidence that habits in this sense would be superfluous.

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We can tentatively identify at least one such system that appears to be comprised of highly general concepts, which can only function properly after some level of formation, namely, the system of core knowledge with respect to food. For more than thirty years, psychologists have been studying the emergence and development of the infant’s ability to distinguish between edible and inedible objects, and between appropriate and healthy, or inappropriate, spoiled, or otherwise unsuitable food. In contrast to adults, older children, and at least some kinds of non-human primates, human infants are remarkably indiscriminate with respect to what they will ingest; one study summarizes that “items regarded by adults as dangerous, disgusting, or inappropriate, and combinations of individually liked foods that are unacceptable to adults were readily accepted by many of the younger children in our sample…. [However,] within the 16 month to five year age range studied, there is a clear developmental trend towards rejection of items that adults consider disgusting or dangerous.” (Rozin)

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Indeed, recent research indicates that the food preferences of young children are not only formed through social interactions, but strongly tied to perceptions of, and feelings about, group identity. This research supports what experience would seem to confirm, that our habituated desires for specific foods may reflect our sense of social identity and a socially mediated sense of what is desirable, seemly, or appropriate for those of our kind. If this is so, then it would appear that at an early stage, the developing child begins to develop normatively laden food preferences, reflecting basic judgments about what one ought to eat.


Young african american father giving milk to her baby girl in a
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This way of construing the development of food preferences is highly suggestive from the standpoint of a Thomist virtue ethicist. The virtue of temperance, for example, is a habitual disposition towards desires and aversions that reflect normative judgments of some kind. Any suggestion that early childhood food preferences develop in accordance with normative judgments will be grist to the mill for a contemporary Thomist. At the same time, we need to be careful not to move too quickly between contemporary psychology and Aquinas’ account of temperance. It is not immediately evident that the normative ideal informing temperance is the same as the normative standards informing the food preferences of young children. This does not mean that recent research disconfirms Aquinas’ analysis of temperance, but it does point to a more interesting way of thinking about the relation between these two very different ways of thinking about our most basic desires.


Kristin Shutts, Kirsten F. Condry, Laurie R. Santos, and Elizabeth S. Spelke, “Core Knowledge and its Limits: The Domain of Food,” Cognition. 2009 Jul; 112 (1): 120–140.

Paul Rozin, Larry Hammer, Harriet Oster, Talia Horowitz and Veronica Marmora, “The Child’s Conception of Food: Differentiation of Categories of Rejected Substances in the 16 Months to 5 Year Age Range,” Appetite, 1986, 7, 141-151.

Samantha P. Fan, Zoe Liberman, Boaz Keysar, Katherine D. Kinzler, “The Exposure Advantage: Early Exposure to a Multilingual Environment Promotes Effective Communication,” Psychological Science.  July 2015 vol. 26 no. 7 1090-1097.

Jean Porter is the John A. O’Brien Professor of Theological Ethics at the University of Notre Dame and Scholar with Virtue, Happiness, & the Meaning of Life.