There’s one persuasion technique that has been consistently shown to work in almost any situation. It’s very practical, can be used by anyone and doesn’t involve a carrot or a stick. In the U.S. it’s known as the ‘But You Are Free’ technique. Over here, we’d probably say, ‘It’s up to you’ or ‘You are free to choose’.

Why does it work so well? Because it tags onto the end of your request a phrase that reaffirms people’s freedom to choose. You’re not forcing them to do something, you’re simply asking them politely and then reminding them that they’ve got a choice.

Their choice.

When my sons were young I would use this technique to stop them from swinging from a dangerous tree, trying to jump over a fast running stream, or just discouraging them to test the temperature of a domestic appliance by holding it against their bare skin. ‘I wouldn’t do that if I were you. But it’s up to you’ I would say. Okay, so maybe it didn’t always work but, on the upside, I did get good value out of the Harrogate and District Hospital A&E service.

But generally speaking, it works a treat. Probably because none of us likes to be ‘persuaded’. By adding ‘It’s up to you’ you are indirectly affirming a person’s freedom to choose. In effect, you’re not threatening their right to say no. Earlier this year, Christopher Carpenter of Western Illinois University carried out research in this area involving some 22,000 people. What he discovered was that by simply adding the phrase ‘But you are free…’, it doubled the chances of people saying ‘yes’ to a request. The only phrase that achieved a higher success rate was ‘Or I’ll kill all your family’.

Just kidding.

But that would probably work too.

So where’s the proof? Well, people have been shown to donate more to good causes, agree more readily to take part in a survey, and give money to someone asking for a bus fare home, simply by adding that phrase. The exact words are not especially important. ‘Totally your choice’ works. As does ‘But obviously, don’t feel obliged’.

When most people would then actually feel more obliged.

The important thing is that the request is made face-to-face, otherwise the power of the technique diminishes. It sometimes works via email, but less so than when delivered in person. What this really underlines is that we don’t like to be hemmed in and have our choices reduced. That only serves to make us even more closed-minded.

As with all effective methods of influence rather than persuasion, this whole technique is about ‘helping’ other people come to the decision you want through their own free will. They need to feel like it was their decision. And it means they are less likely to change their mind later. Respecting people’s autonomy has the happy side-effect of also making them more open to influence rather than persuasion.