Does Eating Family-Style Foster Cooperation or Competition?
New study finds surprising link between how we eat and when we collaborate.
Posted Apr 27, 2019
People who travel internationally learn quickly that different cultures serve food in different ways.
In some countries—China, India, and Morocco, for example—the meal consists of dishes that are shared like the one in the photo. Each person takes a portion of the food and leaves enough so that everyone gets their fair share.
In other countries—France, Germany, and the United States, for example—the meal is served as individual plates of food. Each person eats what they want from their own plate.
Eating from a single, common plate or bowl requires a certain amount of coordination and cooperation. Eating from one's own plate? Not so much.
Eating from shared plates is a common practice in East Asian and South Asian countries. That's not really surprising, given that collectivist cultures socialize children from an early age to play and work well with others and place the welfare of others above their own. According to conventional wisdom, the practice of eating from shared plates is merely a by-product of collectivist norms.
There is, however, another possibility. Maybe the causal arrow flies in the opposite direction. Maybe the simple act of eating from a shared plate leads people to consider the welfare of others and cooperate with them.
It was this possibility that prompted psychologists Kaitlin Woolley and Ayelet Fishbach to conduct three experiments that examined the impact of eating styles on cooperative choices in simulated negotiations. They reported their findings in the April 2019 issue of Psychological Science, a top journal in the field.
In Woolley and Fishbach's first study, 200 students agreed to participate in a study of "how hunger affects decisions." The students were tested in pairs outside a campus café and paid $3 each.
In the separate-eating condition, a research assistant placed two small bowls in front of each participant. One bowl contained 20 grams of tortilla chips; a second bowl contained 25 grams of salsa.
In the shared-eating condition, the research assistant placed two large bowls in the center of the table. One bowl contained 40 grams of chips; the second bowl contained 50 grams of salsa.
Participants were instructed to eat the snacks before playing a decision-making game. In the game, pairs learned they would be negotiating an hourly wage during a labor strike. One member of the pair played the role of a union representative, while the other represented management. The goal was to settle on a wage between $10 an hour (the figure desired by management) and $11 an hour (the figure desired by the union).
Having workers out on strike was costly to both workers and management, so both sides were motivated to reach an agreement as soon as possible. The settlement had to be reached within 22 rounds, each round representing a day on strike.
Pairs sharing food from the same bowl reached an agreement much more quickly than pairs eating from separate bowls. On average, pairs eating chips from a common bowl settled after 8.7 rounds (strike days), while pairs eating separately settled after 13.2 rounds (strike days).
Woolley and Fishbach's second study used a similar procedure. Students outside a campus café played an airfare-pricing game after eating Goldfish crackers, either from a single Ziploc bag or from separate Ziploc bags.
In the airfare-pricing game, one student represented Midwest Airways, and the other represented Air Chicago. In each round, a rep had to choose to implement the standard fare or a discounted fare.
If both reps chose the standard fare, both airlines earned $5 million each. However, if one rep chose the standard fare and the other rep decided to discount fares, the second rep's airline made $7 million while the first rep's airline made only $2 million (because passengers flocked to the airline offering the discount fare). The standard fare was the cooperative choice, because both airlines benefited equally. The discount fare was the competitive choice.
When the two negotiators shared a single bag of crackers, they cooperated on 63 percent of the rounds. However, when the negotiators ate their crackers separately, they cooperated on just 43 percent of the rounds. In other words, eating from "a shared plate" triggered a 47-percent increase in the amount of cooperation between the two parties.
Why does eating from a shared plate promote cooperation? In their third study, Woolley and Fishbach carefully assessed their participants' eating patterns. They noticed that, in the shared condition, most participants physically handed the bag of crackers to their partner at least once. Moreover, nearly 9 in 10 participants waited for their partner to take a cracker before reaching for a cracker themselves. Participants who ate from the same Ziploc bag coordinated their eating in a way that was not necessary when participants had separate bags of crackers.
In their article, Woolley and Fishbach argue persuasively that eating from a shared plate causes people to coordinate their food consumption with others. To eat in a coordinated fashion, people must take the perspective of their partner and modulate their behavior in response to their partner's behavior. These actions foster cooperation.
According to this line of reasoning, people in collectivist societies tend to cooperate with others for two reasons—because of their cultural norms and values, but also because they regularly eat from shared plates.
When I attended Whittier College in the 1970s, meals in the dining hall were served family-style. Kitchen workers delivered large platters of meat, bowls of fruits and vegetables, and baskets of bread to every table. The students at the tables then served themselves.
My memories of those times are admittedly fuzzy, but what I recall is that young people from different states, different social classes, and different religious and political affiliations had spirited yet amiable conversations. It never occurred to me at the time that our liking and respect for each other may have been produced, in part, by the simple fact that we ate from shared plates.
Woolley, K., & Fishbach, A. (2019). Shared plates, shared minds: Consuming from a shared plate promotes cooperation. Psychological Science, 30, 541-552.