Placebic reasons

Ellen Langer, Arthur Blank and Benzion Chanowitz wanted to know how much of everyday compliance involved any thinking at all. Their test was a photocopier in a university library. A researcher approached someone about to use the machine and asked to go first, in one of three forms. "Excuse me, I have five pages. May I use the Xerox machine?" "Excuse me, I have five pages. May I use the Xerox machine, because I'm in a rush?" And "Excuse me, I have five pages. May I use the Xerox machine, because I have to make copies?", a sentence with the grammar of a reason and nothing inside it, since everyone at the machine had copies to make.

With the plain request, 60 per cent let the researcher go ahead. With the real reason, 94 per cent did. With the empty reason, 93 per cent did. The people at the machine were responding to the structure of what they heard, a request followed by "because" and a clause, rather than to what the clause said. Langer called this mindlessness: handling a familiar situation by its form, without processing its content.

The second half of the experiment is the part the popular version drops. The researchers repeated all three requests with twenty pages instead of five. With a request large enough to cost the person something, the empty reason lost its power entirely: 24 per cent agreed, the same as with no reason given. The real reason still helped, but only to 42 per cent. Once the stakes were high enough to be worth attention, people paid it, and the reason had to hold up.

This is the mechanism behind a great deal of marketing and sales copy, and behind the email asks you send every day. For small requests, a click, a reply, a minute of someone's time, what gets you the yes is the form: a request, a "because," a reason. The reason barely has to be good. That is why so much copy that reads as empty still works, and why "because" earns its place in a subject line.

It is also the limit, and the limit is where most people misuse the finding. The moment the ask is large, a purchase, a commitment, a change of supplier, a decision that costs the person something, the shape stops working and the content takes over. Then a weak reason is worse than useless, because it signals that you didn't have a real one. So match the effort to the size of the ask: for small requests, make sure the form is complete; for large ones, make the reason true and specific, and don't expect the word to carry it.

Source: Langer, Blank and Chanowitz, The Mindlessness of Ostensibly Thoughtful Action: The Role of "Placebic" Information in Interpersonal Interaction, Journal of Personality and Social Psychology, 1978. Cialdini describes the experiment in the opening chapter of Influence, 1984.

Influence

Robert Cialdini, 1984

The book on the six, later seven, levers of persuasion, from the researcher who spent years inside sales organisations to see them used. The copier experiment opens it.