A psychological trick to get people to trust you is best used over lunch

Phillip Capper via flickr

Psychologists are increasingly discovering that, while trust can be built gradually over the course of a friendship or a professional relationship, it can also develop super quickly — sometimes over the course of a single meal.

The latest evidence of that phenomenon is a study led by researchers at the University of Chicago Booth School of Business and cited in The Wall Street Journal. A series of four experiments suggests that there's an easy way to make someone you don't know that well trust you: Eat the same food as they do.

In one experiment, 176 undergrad and grad students were divided into pairs and were told that they were going to be eating and evaluating candy. (In reality, the researchers weren't interested in their evaluations — that was just a cover.)

In some cases, both partners ate the same candy; in other cases, they ate different candies.

Then, all participants played a game in which they were assigned to the role of either investor or fund-manager. The investor had to decide how much of their money to invest in a fund-manager. Whatever amount they invested would be doubled, and the fund-manager would decide how to split the sum with the investor.

The researchers wanted to know: Would partners who had eaten the same candy trust each other more than partners who'd eaten different candies? In other words, would investors allot more money to fund-managers when they'd eaten the same candy?

Indeed, results showed that partners did trust each other more in these cases.

Another experiment revealed that partners who ate the same candy reached more mutually satisfying agreements in a negotiation, compared to partners who ate different candies.

Of course, it's possible that finding any similarity makes people trust each other more. So the researchers had a group of participants read stories about partners who either wore the same shirt or ate the same food.

Sure enough, the participants guessed that partners who ate the same food trusted each other more than partners who wore the same shirt. That suggests sharing food is a uniquely effective path to trust.

If you still feel weird about ordering the same food as your interviewer, or your client, or your date, one of the study authors told The Wall Street Journal that getting something similar is fine.

Oh, and the researchers are quick to mention in the paper that you probably shouldn't literally share food with a new acquaintance. So leave the Lady-and-the-Tramp-style spaghetti slurping for at least the second date.

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