Would you be jealous if your significant other ran into a past girlfriend or boyfriend at a New Year’s Eve party?

How about if they exchanged emails? What if they actually met for an hour-long lunch — or an even longer dinner?

Turns out most people would be most bothered by the lunch or dinner.

That’s because people have evolved to recognize that eating together has a physical and social significance beyond food, according to researchers at the Cornell University Food & Brand Lab.

They determined this after a series of experiments.

In the first, 79 undergraduate students were presented with six hypothetical vignettes detailing their romantic partner’s interaction with their ex-romantic partner. The six vignettes included an approximately one-hour correspondence via email, on the phone, over late-morning coffee, lunch, late-afternoon coffee, or dinner.

Sharing a meal with an ex can cause jealousy in your current relationship. (Photo courtesy FreeImages.com/Kristin Smith)

Sharing a meal with an ex can cause jealousy in your current relationship. (Photo courtesy FreeImages.com/Kristin Smith)

Using a 1-to-5 scale, the students were asked to indicate their level of jealousy to each of the hypothetical situations.

The results showed no significant gender differences. In both sexes, there were higher degrees of jealousy for more direct forms of communication.

For example, phone conversations elicited more jealousy than email correspondence. Meals, for any of the conditions, elicited significantly more jealousy than coffee and phone conversations, according to the study’s findings.

In the second experiment, 74 undergraduate students were presented with the same vignettes, but were asked to estimate the jealousy of their best same-sex friend.

For this experiment, there were also no significant gender differences. Phone conversations elicited more jealousy than email, and meals more than coffees.

Dinner provoked more jealousy than both lunch and late afternoon coffee.

According to the researchers, the results indicated a consistent increase in jealousy resulting from face-to-face interactions at meals than interactions that did not involve food.

The results suggest that people recognize that eating together has a social significance beyond food due to commensality, the Cornell researchers claim.

Commensality is eating and drinking at the same table, a fundamental social activity that not only creates, but cements, relationships, according to social scientists.

“The increased jealousy shows that people are attuned to the risks of extra-pair cooperation and that such cooperation is enhanced when sharing a meal,” the Cornell researchers said in their study. “We found a view among people that lunch is not ‘just lunch.’”