If you look carefully, you'll see that the labels on bottles of Stolichnaya vodka sold outside Russia (like these in New York City) read "Premium Vodka," not "Russian Vodka." Craig Barritt/Getty Images for Tribeca Film Festival hide caption

toggle caption Craig Barritt/Getty Images for Tribeca Film Festival

Popular online games like FarmVille use powerful reward systems to get players to spend real-world money on virtual items. Zynga/AP hide caption

toggle caption Zynga/AP

Online Marketers Take Note Of Brains Wired For Rewards

  • Download
  • <iframe src="https://www.npr.org/player/embed/204621796/205058141" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

Can You Help Me Tie My Shoe? Researchers found that when study participants were asked an unusual request, they were more likely later on to perform a favor. iStockphoto.com hide caption

toggle caption iStockphoto.com

Denny's Beer Barrell in Clearfield, Penn. features a 15 pound burger for $39 that is free if the customer can finish it. Jeff Swensen/Getty Images hide caption

toggle caption Jeff Swensen/Getty Images