Tie my shoes, please: How persuasion works (NPR)

Scientists have been studying manipulative techniques and found a few that work. The door-in-the-face technique works by asking for something outrageous, getting turned down, then asking for something much more reasonable. The foot-in-the-door technique is the best-studied and works by asking the time, for example, then making a request. New experiments that rely on making odd requests are showing promise. For example, a passerby requests that you tie his shoe because his back pain prevents him from bending down. A little later, a woman outside a grocery store will ask you to watch her cart of groceries while she goes to find her husband. Researchers found you’d be more likely to mind the grocery cart if you had fulfilled the unusual request first.