While in graduate school, one sociology student collected data from his job as a delivery man on how to collect the best tips:

So in the year that Thompson worked for Jake’s—not the restaurant’s real name, but the moniker the sociologist gave the calzone spot in a paper he published in the Journal of Contemporary Ethnography last year—he found ways to bring in money without sacrificing his dignity. There was one semi-official rule, passed down from Jake’s laid-back manager: You can’t outright ask for tips. Everything else was left up to Thompson and his band of fellow delivery guys.

Here are a few of the tips (and there are nine total):

Look Like a Customer

One of the Jake’s drivers found that his tips were better when he was clean-shaven: A furry face, he found, usually netted him about $2.00, but a clean one landed $2.50, or sometimes even $3.00. Do calzone lovers hate beards? Probably not, the driver theorized—it’s just that the college students he delivered to thought he was younger without the beard. Customers, he found, were more likely to tip if they thought he was a student, too…

Love the Pets

“You know what really works?” one driver asked Thompson. “Dogs. You compliment their dogs.” The driver said that he got down on the floor and played with customers’ pooches. It worked. “They gave me a five!” he said.

The Receipt Trick

One of Thompson’s personal favorite tricks came at the very end of the delivery interaction, when a customer using a credit card had to sign the receipt. If she left the tip line conspicuously blank, Thompson would turn back to her and say, “Sorry, boss needs you to fill out the entire thing!” That forced the customer to either come out and admit that she was purposely stiffing him, or wilt under his passive aggression. Cha-ching!

The Change Trick(s)

There are a few ways to pull the change trick. The first, another one of Thompson’s favorites, was wide-eyed innocence. “Great, a five dollar tip!” he would exclaim if a customer had given him a nice round bill, possibly hoping for change. “Awesome!” Only the customers who really, really wanted to leave a bad tip—and were willing to go through a very uncomfortable social interaction to do so—would demand their change back.

Two quick thoughts:

1. Training in sociology, particularly in face-to-face interaction, could go a long ways here. A number of these tips involve manipulating the particular social situation to the delivery person’s advantage. Instead of feeling embarrassed to be chasing a tip, the onus can effectively be put on the purchaser to go out of their way to not give a tip. In other words, this is all about impression management.

2. There is some interesting work in sociology regarding jobs or situations where money is clearly involved but can’t be discussed. This is one; it is uncouth to openly ask for a people but people can be acceptably nudged. Or in the art world, artists can’t quite openly say that they are in it to become wealthy but they clearly need to sell art to survive (and to gain status). Or, certain items like life insurance have to become morally acceptable (a process traced by sociologist Viviana Zelizer) before people will purchase them. Even in our world where economics and money seem like pretty powerful forces, there are still social constraints.