At the end of every dinner with friends comes that awkward moment when you have to split the check. This moment has caused so much consternation that a trio of scientists took real groups of people out to dinner to figure out how it should be done.
The Unscrupulous Diner's Dilemma
Say you are a person who likes a free meal more than you like friends. (Hey, I'm not judging. Given the results of this experiment, it looks like you're pretty common.) You get together with five friends at a restaurant, and at the beginning of the meal, everyone decides to split the check evenly. You have a possible advantage. You wouldn't normally order the most expensive meal, because the slightly nicer food isn't worth the extra money it costs. But it's well worth one-sixth the extra cost, so if you get the most expensive option, the rest of the table will pay for most of your nicer food.
Remember that you're not the only one at that table. If everyone orders the expensive food, then everyone will end up bearing the entire cost of that extra expense. Assuming no one at the table considers the expensive food worth the sticker price, everyone at the table got the worst deal possible by trying to get the best deal possible. At least, that's how it works in theory, but how do people in restaurants really act? Are we all unscrupulous diners?
The Field Test!
Three scientists, Uri Gneezy, Ernan Haruvy, and Hadas Yafe, wanted to find out how unscrupulous we all are, so they actually got groups of strangers to come out and eat at a restaurant. They covered their tracks by having people fill out 10-minute surveys on their emotional states before and after eating, pretending they were looking for emotions, rather than ethics. All subjects were paid about 20 dollars before lunch started, and they were all asked how much they would prefer to pay for their meals. Some were told that they would all pay individually. Some were told that they would split the check evenly. Some were told that they were getting a free meal. To keep people from being self-conscious while ordering, the subjects all filled out an order sheet, which the waiters (who had to be getting a kick out of the experiment) were told to pick up without comment.
To no one's surprise, the people who paid individually were the most frugal, the people getting the free lunch were most extravagant, and the people who split the bill were in the middle, and therefore slightly unscrupulous. The scientists then did a little variation on the experiment. They invited a new group of people to the restaurant, and made them pay individually, but had them all pay one-sixth of what their food cost. This effectively got them the benefits of the split pay system, but without the crushing guilt of reaching into their fellow diners' pockets. The 1/6th diners paid just about what the split-pay people did. So it seems we just like a good cheap lunch, no matter who it's coming from.
Just to finish the process off, the scientists took a look at how people would react if they ran through the experiment in a lab setting. Contrary to what happened at the actual restaurant, in the lab people's orders when they "split the check" looked very much like their orders when they all paid individually. Only the 1/6th payers had the lobster. What people do in a lab, and what they do at the table, seem to be very different things.
The Implications Of Our Unscrupulous Behavior
So what does this say about us, except that we like fancy food on the cheap? For one thing, it shows that we're selfish and inefficient. Get a group of people together and they will find a way to force everyone to pay for things that none of them think are worth the money.
It shows that when you eat with friends you should each pay individually. This isn't a huge change. On the experimental survey, about 80% of the people in the experiment wanted to pay their own way.
More intriguingly, the paper hints at how we make our decisions. Looked at in a positive way, it's an argument for maximum freedom. Give people the ability to opt into a system that holds them accountable for their choices, and they'll make choices that result in maximum efficiency. Force people into a system they don't choose, and they will take advantage of it, even if it makes for a worse system overall. The authors write that "This inefficiency is the result of people all playing the equilibrium of the game, even if they prefer to be in a different game." Then again, it also hints at resentment. People would rather grab food that they don't really think is worth it, rather than be the only sucker who ordered a coffee and had to pay $10 for it. Better for everyone to have to pay more than they want than to subsidize even a small part of one person's cheap lunch.
But there's also a certain sense of efficient whimsy to the study. The scientists suggest an interesting twist on offering people a free meal. When people are given a free meal, they'll order the most expensive stuff. This works out badly for everyone, as the payer is paying for food that the consumer doesn't consider worth the money. If the payer offered to either pay for the most expensive meal, or pay for the cheaper meal and offer the consumer a little cash bonus (less than the price difference between the meals), both people would be happier. By paying less, they'd both feel they gained more.