Training manuals often advise businesspeople to mirror their customers. Credit: © Corbis

Waitresses who copy their customers' behaviour get substantially bigger tips than those who don't, Dutch psychologists have discovered1.

"Mimicry creates bonds between people - it induces a sense of 'we-ness'," says Rick van Baaren of the University of Nijmegen. "You know that what you're doing is ok, and you become more generous."

Van Baaren's team studied staff in an American-style restaurant in southern Holland. In half of the tests, they primed a waitress to repeat customers' orders back to them. In the other half, she said something else positive, such as "Coming right up!"

When copycatting, the waitresses' average tip almost doubled, to nearly 3 guilders (US$1.20). Service charge is included in Dutch restaurant bills, tips are a small additional gift.

The experiment is the first to show that mimicry has concrete benefits, van Baaren claims, although many understand its benefits implicitly. " A good salesperson knows from experience that people like to hear and see themselves," he says. Business training manuals often advise mirroring the customer.

Kindness triggered by mimicry can spread far and wide. In other experiments, the team found that just after being aped, people are more helpful towards anyone else in the vicinity, and give more to charity2.

But this is just one of a battery of ploys that waiting staff can use to increase customers' generosity. Other studies have shown that smiling, greeting and touching the customer, and crouching down beside them while taking orders also lead to bigger tips.