Let’s think about queueing. Under what circumstances would you be willing to let another person cut in front of you? Which single word would strengthen the persuasion attempts?

The word is “because”. The behavioural scientist Ellen Langer and her colleagues decided to put the persuasive power of this word to the test. In one study, Langer arranged for a stranger to approach someone waiting in line to use a photocopier and simply ask, “Excuse me, I have five pages. May I use the Xerox machine?” After this direct request, 60 per cent of people agreed to allow the stranger in ahead of them.

When the stranger followed the request with a reason, however (“May I use the Xerox machine because I’m in a rush?”), almost everyone (94 per cent) complied.

This may not seem surprising. After all, providing a solid reason for the request justifies asking to jump ahead. But Langer tested one more version of the request. This time the stranger used the word “because” but followed it with a meaningless reason. Specifically, the stranger said, “May I use the Xerox machine, because I have to make copies?”

Despite the tautological hollowness of the “reason” provided, it generated nearly the same elevated levels of compliance (93 per cent).

The study shows the unique motivational influence of the word “because”, which gets its persuasive power from the reinforced association between “because” and the good rationales that typically follow it.

© Robert B. Cialdini, Steve Martin and Noah Goldstein 2007

Extracted from YES! Fifty Secrets from the Science of Persuasion, to be published by Profile Books on November 12, 2007, at £8.99, available from Times BooksFirst at £8.54, free p&p. 0870 1608080

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