By Peter M. Vishton, PhD, William & Mary
Edited by Kate Findley and proofread by Angela Shoemaker, Wondrium Daily
Negotiations are a part of life, especially if you work in the sales or service industry, yet they can be stressful for many people. Professor Vishton explains a simple tip that takes off the pressure of “making the sale.”

The Reciprocity Principle for Servers
The reciprocity principle dictates that if you give a gift to someone, that person will naturally want to give something back to you. A classic study was conducted with waiters and patrons in a restaurant in Arizona.
Waiters gave their normal service—they took orders, delivered food, had conversations with the diners, and eventually, brought the bill. For a randomly selected half of the patrons, the bill was delivered along with a single after-dinner mint for everyone at the table.
For the other half, the bill arrived without the mint. The researchers recorded the tips that the patrons left. The mints resulted in a 3% increase in the size of the average tip.
That’s a small increase, but it was statistically very significant. That is, based on the number of patrons and the typical variation in tip amount, the 3% increase was almost certainly not due to random chance.
In another scenario, the bill was delivered with two mints for each person at the table. The tips increased by 14%. For a $100.00 dinner bill, this is substantial money.
That money is given for the same service, the same food, and in the same restaurant. The only difference is an extra few mints that cost about two cents each.
In yet another scenario of the study, the waiters did something that emphasized the gift giving aspect of the interaction. The waiter would deliver the bill with one mint per person, and then start to walk away. The waiter would then stop, turn back to the table, and say something like, “You know what. You’ve been really nice tonight. Here are some extra mints for you.”
Now the tips go up by 23%. This study, conducted by Robert Cialdini and his collaborators, is one of dozens that they have performed to explore this reciprocity effect.
Power of Personalization
Researchers have found similar effects regarding tips for people who clean hotel rooms. If the person cleaning the room leaves an envelope, a certain proportion of hotel patrons will leave a tip.
If the cleaning person leaves a mint, the tips rise. If the mint is accompanied by a personalized note, indicating that the mint is intended as a gift, the tips increase substantially more.
The amounts of money involved in all of these interactions is relatively small, but the principle scales up to larger transactions as well. Negotiations for multimillion dollar deals can incur swings of enormous amounts of money if a small gift is given early in the process. Sometimes that gift is a cup of coffee or a pen.
Sometimes the gift comes in the form of a small concession early on in the negotiation. People who make their living through negotiating contracts know this reciprocity principle well. As the details of some deal are hammered out, they will often agree to concede to some small term and then ask for a much larger concession from the other side.
“If you ever negotiate over the purchase of a house or a car, this will almost certainly be a useful piece of information,” Professor Vishton said. “There’s a reason that when you show up in the office of a realtor or a car dealer, they will almost immediately offer you at least one small gift. It works.”
Reciprocity with Computer Doing the Asking
One recent study even found that the reciprocity principle works when computers are doing the asking. Participants in this study completed two tasks. They were not told that the tasks were related to one another.
The participants first completed a web research task. An interactive computer system offered to help them to complete the task, and then provided that assistance. Half of the participants were randomly assigned to the same computer scenario.
The second group of participants switched computers. They completed their second task on a different machine that hadn’t recently been helpful. The computer then requested assistance from the participants, asking for help with a color calibration task.
The computer would repeatedly present colored rectangles on the screen and ask participants to respond by indicating the shade of that color. The participant was also offered the option of ending this task at any time.
The results showed that after a computer had been helpful, if participants continued working while using that machine, they performed an increased number of color judgments before ending the task. Our human reciprocity reflex seems to be so strong that it can even be triggered by requests from inanimate devices like a computer.
According to Professor Vishton, you should keep three critical things in mind to make the best use of this reciprocity principle—this reciprocity reflex, actually. First, give a relatively small gift before asking for something.
Second, make it apparent to the recipient that it is something you are doing for them, and third, make the gift as personal as possible.
If you give a pen or a cup of coffee, it’s only going to affect you if you perceive that item as a gift. If it seems like something that everyone receives as a matter of regular course, then the reflex won’t be triggered.
This article was edited by Kate Findley, Writer for Wondrium Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for Wondrium Daily.

Peter M. Vishton is an Associate Professor of Psychology at William & Mary. He earned his PhD in Psychology and Cognitive Science from Cornell University. Before joining the faculty of William & Mary, he taught at Northwestern University and served as the program director for developmental and learning sciences at the National Science Foundation.