One question that got 77% to say yes

Don't ask: "Would you fill in a short survey?"

In one study Cialdini describes in Pre-Suasion, only 29 percent of shoppers said yes to that.

Then researchers asked a different question first: "Do you consider yourself a helpful person?" Almost everyone said yes. And then 77 percent agreed to the survey. That's close to three times as many.

One question frames everything that follows. Use it with care, and never to trick anyone.