An interesting study from Italian researches says that if you want someone to do something, talk into the person's right ear.

The study says the right ear is connected to the left side of the brain, which is better at processing speech and language. Researchers also say watch somebody talk on the phone--most people will naturally hold the telephone to their right ear.

This got me thinking. This research would be good to test in the car if you are riding in the passenger seat. The driver's right ear is always pointing in your direction when you are a passenger--unless you are driving in England. So, ask for some things, and see if it works.