Got something to say to this podcast? Send a voicemail, and you might hear yourself on the next episode!

The foot-in-the-door technique takes its name from mid-century door-to-door salesmen who wedged a shoe in the frame so a customer could not shut the door, then built that small concession into a sale. In 1966 Stanford researchers Jonathan Freedman and Scott Fraser tested it formally. They phoned California homemakers to ask a few questions about household cleaning products, then called back three days later asking to let five or six men spend two hours going through their cupboards to inventory their products. Women who had answered the first questions were more than twice as likely to agree as a control group asked only the large request. In another test, only about 17 percent of homeowners agreed to put a large, ugly Drive Carefully sign in their yard, but 76 percent agreed if they had first displayed a three-inch Be a Safe Driver sign in a window.

The leading explanation is Daryl Bem’s self-perception theory: people infer their attitudes by watching their own behavior, so a small yes reshapes their identity. In 1999 Jerry Burger of Santa Clara University argued instead for a simpler pull toward consistency and commitment. The technique also works by email, and its opposite, the door-in-the-face, starts with a huge request designed to be refused. In a 2011 Hong Kong study, the foot-in-the-door got 12 of 20 second graders to take on a 20-item arithmetic worksheet, while the door-in-the-face got 18 of 20.

• People who first answered questions about cancer were more likely to let volunteers into their homes to collect donations for the American Cancer Society.
• In a recycling study, people paid nothing to display a small sign kept recycling longer than those paid $1 or $3.
• Swanson, Sherman and Sherman found a small neutral request made a later anxiety-producing request feel less stressful.
• A 1989 study found that filling out an organ donation questionnaire raised willingness to register, whether it had five questions or 20.
• Dariusz Dolinski’s 2011 foot-in-the-face technique, two requests of equal difficulty, yielded compliance of 63 to 68 percent.