After knocking on every door on the block on Halloween night, many children come home and promptly set up what looks unmistakably like a bargaining table. In the hours before bedtime, an elementary kind of commerce ensues: Reese’s Peanut Butter Cups and full-size Butterfingers will either be hoarded in the face of generous offers or traded at a steep exchange rate for Skittles or Starbursts. Off-brand Smarties will likely be offloaded into the plastic pumpkin-shaped  buckets of unsuspecting toddlers, replacing the Sour Patch Kids, which their devious older siblings have convinced them are inferior.

The obvious reason to trade Halloween treats is that kids love candy—and maximizing the amount of the types of candy they love best is an appealing prospect. Plus, in the best-case scenario, a trade is a win-win: You not only get rid of something you don’t want to eat—the candy that will sit at the bottom of your trick-or-treat bag until it eventually gets thrown out—but you also gain something that you do want to eat in return.

Experts, however, suggest that a few other forces drive the Halloween-candy trade. For example, Felix Warneken, a psychology professor at the University of Michigan whose research focuses on cooperation among young children, sees in the candy trade an expression of small children’s tendency to impulsively help others. “Toddlers as young as 14 or 18 months of age, when they witness that someone has a practical problem—someone’s looking for something, they don’t know how to open a box, an object is out of reach, a door is closed and they can’t get through it—kids spontaneously help out,” Warneken told us. If the opportunity appears to give peers the candy they most want to eat, kids are likely to want to take it.  

Read the full article at The Atlantic.